Guidelines for Preventing the Transmission of Mycobacterium Tuberculosis in Health-Care Facilities, 1994
Federal RegisterOct 28, 1994
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SUMMARY: The purpose of this notice is to print the final ``Guidelines
for Preventing the Transmission of Mycobacterium tuberculosis in
Health-Care Facilities, 1994,'' and a summary of comments and responses
to those comments.
EFFECTIVE DATE: October 28, 1994.
ADDRESSES: This document is also being printed in its entirety as a
Morbidity and Mortality Weekly Report (MMWR), Recommendations and
Reports. For copies of the MMWR printing, call CDC's Voice Information
System (VIS) at (404) 639-1819 or write to the Centers for Disease
Control and Prevention (CDC), Information Services Office, Mailstop E-
06, Atlanta, GA 30333. An electronic version of this document will be
available via Anonymous FTP from ftp.cdc.gov after November 18. Type
``Anonymous'' for the user name and your e-mail address for the
password. Select the pub directory, then the tbdoc subdirectory.
Retrieve the README file for instructions on document viewing and
printing.
FOR FURTHER INFORMATION CONTACT: CDC's Voice Information System at
(404) 639-1819.
SUPPLEMENTARY INFORMATION:
Background
On October 12, 1993, CDC published ``Draft Guidelines for
Preventing the Transmission of Tuberculosis in Health-Care Facilities,
Second Edition,'' in the Federal Register at 58 FR 52810 with a 60-day
comment period (which was extended to January 13, 1994). More than 2500
comments were received and reviewed. The following represents a summary
of all major comments and a response to each. All comments were
reviewed and considered in developing the final guidelines. Changes
were also made to increase clarity and readability.
Comments and Responses
Section I. Introduction
Section II. Recommendations
A. Assignment of Responsibility
No comments received on this section.
B. Risk Assessment, Development of the TB Control Plan, and Periodic
Reassessment
Comments: Provide more flexibility in levels of risk to accommodate
facilities that rarely or never provide services to patients with
tuberculosis.
Response: Two new categories--``very low risk'' and ``minimal
risk''--were added to accommodate such facilities.
Comments: Rationale for selecting six patients per year in a given
area as a criterion for risk level seems arbitrarily defined.
Response: This criterion is based on surveys conducted by CDC in
conjunction with the American Hospital Association, the Society for
Health Care Epidemiology of America, and the Association for
Professionals in Infection Control and Epidemiology. These surveys
suggest an increased risk of tuberculin skin test conversion in
employees working in facilities admitting six or more TB patients per
year.
Comments: Repeat skin testing at 3-month intervals in high-risk
settings is too frequent.
Response: The high-risk setting is essentially an outbreak setting,
in which there is evidence of transmission of Mycobacterium
tuberculosis. In this situation, it is reasonable to conduct follow-up
skin testing 12 weeks (3 months) after the initial testing. If there is
no evidence of further transmission and any deficiencies in infection
control practices and facilities have been corrected, the area is no
longer considered high risk, and there is no need to continue testing
every 3 months.
Comments: A cluster of skin test conversions is defined as two or
more conversions in one area within 3 months; however, because of the
limitations of skin testing, this may not represent true conversions
due to nosocomial transmission.
Response: It is assumed that a cluster would be investigated to
determine the likelihood that it truly represents nosocomial
transmission. The situation would be classified as high risk only if
this evaluation supported a conclusion that nosocomial transmission had
occurred. The recommendation will be modified to clarify this point.
Comments: Retesting all employees in a area when a single
conversion has occurred may not be warranted.
Response: Clarified wording of this section.
C. Detection of Patients Who Have Active TB
Comments: Provide more information and place more emphasis on early
detection, specifically those categories of patients in whom TB should
be suspected.
Response: Reemphasized the need for protocols for early detection
and the need to review and revise these protocols periodically. In
addition, explained that the index of suspicion varies from place to
place, depending on various factors, including the prevalence of
infection in the population served.
Comments: Increase the recommended turnaround time for stat smears
for laboratories unable to use rapid methods and remove the term ``stat
smears'' from recommendations.
Response: Reemphasized the importance of rapid laboratory results.
Discouraged batching of specimens and added the recommendation that
laboratories that perform mycobacterial tests infrequently refer
specimens to an experienced laboratory. Removed the term ``stat
smears''.
D. Management of Patients in Ambulatory Care Settings and Emergency
Rooms
Comments: Clarify the requirement that patients should wear
surgical masks but that health care workers (HCWs) must wear
particulate respirators.
Response: Added a footnote to explain the rationale for each: one
to protect the worker from infection and the other to decrease the
amount of droplet nuclei in the air produced by the patient.
Comments: Do not require isolation rooms in all ambulatory care
settings.
Response: Restated and clarified that if TB patients are seen
infrequently or not at all in a facility, an isolation room is not
needed. However, there must be a protocol for referral and periodic
risk assessment.
E. Management of Hospitalized Patients With TB
Comments: Do not require isolation for most or all pediatric
patients.
Response: Provided some examples of potentially infectious
pediatric TB patients and added a section explaining the need to
evaluate parents as possible source of infection.
Comments: Radiology should not, and in many facilities, cannot have
a separate area for TB patients.
Response: Clarified the section to refer only to facilities where
many TB patients are seen.
Comments: Provide clearer recommendations for visitors and their
use of respiratory protection.
Response: Expanded the recommendations to make clearer.
Comments: Requiring three negative smears to release a patient from
isolation is excessive and unnecessary, especially for suspected TB
cases.
Response: Clarified: if TB has been ruled out, there is no need to
retain the patient in isolation. Reiterated that if TB has been
confirmed the patient should have three consecutive negative sputum
smears collected on different days.
Comments: The recommendation that TB patients not be discharged to
home if an HIV-infected person or young children are in the household
is potentially problematic.
Response: Clarified that this is one of many factors that should be
taken into consideration when planning to discharge TB patients, not a
hard-and-fast rule.
Comments: Labeling door TB Isolation would breach patient
confidentiality.
Response: Recommended using the term Isolation rather than TB
Isolation giving hospitals the flexibility to label doors according to
individual policies or practices.
F. Engineering Controls
Ultraviolet Germicidal Irradiation
Comments: Data are insufficient to recommend the use of UVGI.
Greater emphasis should be placed on the use of UVGI in health care
settings.
Response: No change. No new information was provided and the
current guidelines were considered appropriate.
Ventilation
Comments: Provide specific recommendations on engineering controls
as they relate to risk level. Provide information on how to evaluate
air changes per hour (ACHs). There are no data to support requirement
for six or more ACHs.
Response: Clarified: 6 ACHs are an absolute minimum, and a level of
12 or more ACHs are recommended, especially in new construction.
Referred to table S3-1, which provides the number of air changes per
hour and the minutes required for removal efficiencies of 90.0%, 99.0%,
and 99.9%. The 12 ACHs or more recommendation was arrived at by both
use of this table and NIOSH experimental data. Added discussion on the
benefits of higher ventilation and recommended ideal performance
criteria.
Comments: Provide retrofit information and some examples of
alternative methods for achieving required ventilation.
Response: In response to requests for information on alternative
methods, retrofit information, and interim guidelines, expanded the
introduction to this section and introduced a clearer hierarchy of
ventilation methods.
Comments: Provide clearer directions on bronchoscopy location and
ventilation requirements.
Response: The confusion about bronchoscopy location resulted from
inconsistency in the guidelines in relation to performing the procedure
in the operating room vs. an area of patient isolation. Clarified this
point.
Room Units
Comments: Provide information on room air ``cleaning'' units. Can
these units serve as a substitute for not having six or more ACHs?
Response: Revised the document to present more clearly the
potential use of air cleaning units in areas where air changes are
limited and to set their place in a control hierarchy. In addition,
further clarified the importance of placement, performance, and
potential limitations. Added a statement that manufacturers of these
units should provide documentation of both the efficiency of the HEPA
filter and the efficiency of the device in lowering air contaminant
levels.
Negative Pressure
Comments: Because smoke can be an irritant, the use of smoke tubes
for continuous pressure monitoring should be replaced with flutter
strips. Daily monitoring of negative pressure is unnecessary and labor
intensive.
Response: Made no change in the recommended monitoring schedule.
The concern over the use of smoke tubes is unfounded. Controlled tests
by NIOSH have shown that the quantity of smoke that is released is so
minute that it is not measurable in the air. The location of the
patient and the length of time the patient is exposed dilute the smoke
to several orders of magnitude below an 8-hour exposure limit. It is
not practical and often not effective to use flutter strips or
continuous monitoring devices as alternatives to indicate directional
air movement. The air flow (due usually to the small clearance area
under a door) is insufficient to move the flutter strip. Likewise, low
negative pressure, which will satisfactorily provide adequate
directional air flow into the isolation room, may not be readable on
continuous monitoring devices. Devices must be capable of reading 0.001
inch of water, the established minimum, to be effective. Clarified the
overall guidance in this area by indicating the use of smoke as the
optimum test procedure and clearly stating the potential results of
flutter strips and continuous instrumentation. Used illustrations to
clarify procedures for setting negative pressure.
HEPA Filtration
Comments: The recommendations on the use of HEPA filtration in a
ventilation system are not supported by the data. The purpose of its
use is unclear.
Response: Addressed the general confusion on the use of HEPA
filtration by rewording the section.
Comments: Provide information on the necessity of ``bag in--bag
out'' and ``red bag'' use when changing filters.
Response: Eliminated the bag in--bag out requirement since there is
no evidence that it is needed. Retained the red bag recommendation
(treating filters as infectious waste).
G. Respiratory Protection and Supplement 4. Respiratory Protection
Comments: HEPA filtered masks are too expensive, and no data
support their use. Instituting a fit-testing program and, in general, a
respiratory protection program is too expensive. HCWs will not wear the
masks. The masks are uncomfortable, impede communication, and interfere
with general patient care.
Response: Retained the original performance criteria on respiratory
protection; however, details on specific respirators such as dust-mist
and dust-fume-mist were removed. Removed the respiratory protection
table and accompanying performance characteristics in the supplement in
anticipation of the new certification process. Retained the
explanations about fit, fit testing and fit checking, and the elements
of a respiratory protection program. Added a statement about ongoing
research being conducted on various forms of respiratory protection.
Comments: The performance criteria for respiratory protection for
HCWs exposed to tuberculosis fail to take into consideration the
potential higher level of risk for workers in selected settings (e.g.,
bronchoscopy performed on patients suspected of having TB or autopsy
performed on deceased persons suspected of having TB at the time of
death).
Response: Clarified that the facility's risk assessment may
identify those limited settings where the estimated risk for
transmission of M. tuberculosis may be such that a level of respiratory
protection exceeding the standard criteria is appropriate.
Comments: NIOSH certification process should be changed to
accommodate the certification of a more appropriate mask for use in
health care settings.
Response: On May 24, 1994, CDC published in the Federal Register
(59 FR 26850) a Notice of Proposed Rule Making on revised certification
requirements for respiratory protective devices. The certification of
air-purifying respirators under these proposed requirements would
enable respirator users to select from a broader range of certified
respirators that meet the current performance criteria in this
document.
Comments: Provide information on the storage and reuse of
respirators.
Response: Expanded the general guidelines on the reuse of
respirators classified as disposable and those with replaceable
filters. Retained the original suggestion to refer to manufacturers
recommendations concerning storage and reuse.
Comment: It is unclear which facilities must have a respiratory
protection program.
Response: Clarified that facilities that do not have isolation
rooms for TB, that do not perform cough-inducing procedures, and refer
all potential TB patients need not have a respirator program but must
perform a periodic risk assessment, have protocols for referral, and an
infection control plan that is periodically reviewed.
H. Cough-Inducing Procedures
No comments were received that differed substantively from those
covered in other sections of the document.
I. Education and Training of Health-Care Workers
Comments: In general, the comments supported the concept of
education for HCWs. Persons from a number of specialties noted that
educational programs should be flexible and should allow for the
selection of information to be included in these programs and that the
frequency of training should be based on the risk of TB transmission in
the facility or area. Some suggested emphasis on educating physicians
in the early recognition and proper treatment for persons with
tuberculosis. Because of difficulties with compliance with attendance
and the time needed away from the job in the busy health care
environment, concern was expressed about the increasing requirements
for mandatory annual educational training sessions on various subjects
(bloodborne pathogens, fire safety, hazardous exposure). A few persons
suggested that CDC provide standardized training materials. A few
commented on the expense of the training program, including the
respirator training program.
Response: Modified section to allow more flexibility in selection
of topics to cover and frequency of education.
J. Health Care Worker Counseling, Screening and Evaluation
Counseling
Comments: Most of the comments on this section were very favorable.
Some persons commented that the HIV-infected HCW may not report their
infection to the facility and asked about the facility's responsibility
to HCWs and to patients should this occur. Some expressed concern about
confidentiality and about the Americans with Disabilities Act.
Response: No changes were considered necessary.
Screening HCWs for Active Disease
Comments: Evaluation of every HCW with a cough of 2 weeks or
greater duration is excessive.
Response: Reemphasized the need to tailor each program to fit the
situation. The infection rate in a particular facility, the time of
year (e.g., flu season), the potential exposure of individual workers--
all these need to be taken into consideration.
Screening HCWs for Latent TB Infection
Comments: Annual PPD testing in areas of low prevalence is
unnecessary. It is unclear which HCWs should be tested. Provide clearer
information on the number of conversions during a specified period to
trigger the testing of others from the same area or group.
Response: Modified this section and coordinated it with
recommendations in the risk assessment and the skin testing supplement,
which give clearer guidance on who should be tested and how frequently.
Comments: Two-step skin testing is not necessary for all HCWs,
especially those who are transferring from hospitals and whose PPD
results are negative and those from areas where the prevalence of
booster phenomenon is low or where boosting was assessed as no problem.
Response: Clarified that 2-step testing is not necessary if an HCW
has had a documented negative PPD result in the past 12 months or if
the institution has determined that boosting is not common in their
population. Also added the potential consequences of misinterpreting a
boosted reaction as a new infection.
Evaluation and Management of Health Care Workers With Positive PPD
Tests
Evaluation
Comments: M. tuberculosis antimicrobial susceptibilities should be
recorded in the HCW's medical record and given to the employee if he or
she leaves the facility. The HCW can then be put on appropriate therapy
if active disease develops. Persons who are PPD positive and have not
had adequate preventive therapy should be monitored at least annually.
Response: Added these recommendations to this section.
Routine and Follow-Up Chest Radiographs
Comments: Consideration should be given to performing chest
radiographs on HCWs whose PPD tests are positive.
Response: Reemphasized the need to monitor more frequently for
symptoms of TB in high-risk persons but retained the statement that
regular chest radiographs have not been shown to be effective in
detecting TB in these persons.
Work Restrictions
Comments: Requiring three consecutive negative smears before an HCW
who is receiving treatment for active TB can return to work is
excessive. A person who has improved does not cough and does not
produce sputum and may be kept off duty unnecessarily.
Response: Confusion had been caused by an incorrect wording in the
guidelines, that ``negative smears on consecutive days'' were required.
This has been clarified. The recommendation for 3 consecutive negative
smears collected on separate days was deemed appropriate and retained.
Comments: If an HCW who has a positive skin test result does not
take preventive therapy, the HCW should be required to be seen and
interviewed frequently.
Response: The frequency of follow-up was not specified to allow for
flexibility.
Supplement 2
Comment: HCWs should be allowed to read their own skin test
results.
Response: Retained the recommendation that they not read their own
test results and cited a reference as to why they should not.
Comment: Clarification is needed on what constitutes a positive
skin test result for HCWs.
Response: Added to the recommendation that a HCW may be considered
positive if the induration is 10 mm or more and referred to the
Diagnostic Standards (ATS/CDC statement).
K. Problem Evaluation
Comments and subsequent changes made in the risk assessment section
also apply here. Revised this section.
L. Coordination With Public Health Department
No substantive comments or questions received on this section.
M. Additional Considerations for Selected Areas
Comment: What controls are needed in special areas such as hospices
and nursing homes?
Response: Added a statement on the need to conduct a risk
assessment and have an infection control plan, which should be reviewed
and revised regularly. For hospices and nursing homes, it was clarified
that TB isolation rooms are not needed if they do not provide care to
TB patients. Restated the need for a referral protocol with periodic
review.
Supplement 5 Decontamination: Cleaning, Disinfecting, and Sterilizing
of Patient-Care Equipment
Comments: Only one comment on this section concerned the cleaning
of ventilation ducts.
Response: No changes were considered necessary.
Revised Guidelines
Following are the final guidelines based on analysis of the
comments described above.
Dated: October 19, 1994.
Arthur C. Jackson,
Associate Director for Management and Operations, Centers for Disease
Control and Prevention (CDC).
Guidelines for Preventing the Transmission of Mycobacterium
Tuberculosis in Health-Care Facilities, 1994
Contents
Executive Summary
I. Introduction
A. Purpose of Document
B. Epidemiology, Transmission, and Pathogenesis of TB
C. Risk for Nosocomial Transmission of M. tuberculosis
D. Fundamentals of TB Infection Control
II. Recommendations
A. Assignment of Responsibility
B. Risk Assessment, Development of the TB Infection-Control
Plan, and Periodic Reassessment
1. Risk assessment
a. General
b. Community TB profile
c. Case surveillance
d. Analysis of HCW PPD test screening data
e. Review of TB patient medical records
f. Observation of TB infection-control practices
g. Engineering evaluation
2. Development of the TB Infection-Control Plan
3. Periodic Reassessment
4. Examples of Risk Assessment
C. Identifying, Evaluating, and Initiating Treatment for
Patients Who May Have Active TB
1. Identifying patients who may have active TB
2. Diagnostic evaluation for active TB
3. Initiation of treatment for suspected or confirmed TB
D. Management of Patients Who May Have Active TB in Ambulatory-
Care Settings and Emergency Departments
E. Management of Hospitalized Patients Who Have Confirmed or
Suspected TB
1. Initiation of isolation for TB
2. TB isolation practices
3. The TB isolation room
4. Discontinuation of TB isolation
5. Discharge planning
F. Engineering Control Recommendations
1. General ventilation
2. Additional engineering control approaches
a. HEPA filtration
b. UVGI
G. Respiratory Protection
H. Cough-Inducing and Aerosol-Generating Procedures
1. General guidelines
2. Special considerations for bronchoscopy
3. Special considerations for the administration of aerosolized
pentamidine
I. Education and Training of HCWs
J. HCW Counseling, Screening, and Evaluation
1. Counseling HCWs regarding TB
2. Screening HCWs for active TB
3. Screening HCWs for latent TB infection
4. Evaluation and management of HCWs who have positive PPD test
results or active TB
a. Evaluation
b. Routine and follow-up chest radiographs
c. Workplace restrictions
(1) Active TB
(2) Latent TB infection
K. Problem Evaluation
1. Investigating PPD test conversions and active TB in HCWs
a. Investigating PPD test conversions in HCWs
b. Investigating cases of active TB in HCWs
2. Investigating possible patient-to-patient transmission of M.
tuberculosis
3. Investigating contacts of patients and HCWs who have
infectious TB
L. Coordination with the Public Health Department
M. Additional Considerations for Selected Areas in Health-Care
Facilities and Other Health-Care settings
1. Selected areas in health-care facilities
a. Operating rooms
b. Autopsy rooms
c. Laboratories
2. Other health-care settings
a. Emergency medical services
b. Hospices
c. Long-term care facilities
d. Correctional facilities
e. Dental settings
f. Home-health-care settings
g. Medical offices
Supplement 1: Determining the Infectiousness of a TB Patient
Supplement 2: Diagnosis and Treatment of Latent TB Infection and
Active TB
I. Diagnostic Procedures for TB Infection and Disease
A. PPD Skin Testing and Anergy Testing
1. Application and reading of PPD skin tests
2. Interpretation of PPD skin tests
a. General
b. HCWs
3. Anergy testing
4. Pregnancy and PPD skin testing
5. BCG vaccination and PPD skin testing
6. The booster phenomenon
B. Chest Radiography
C. Bacteriology
II. Preventive Therapy for Latent TB Infection and Treatment of
Active TB
A. Preventive Therapy for Latent TB Infection
B. Treatment of Patients Who Have Active TB
Supplement 3: Engineering Controls
I. Introduction
II. Ventilation
A. Local Exhaust Ventilation
1. Enclosing devices
2. Exterior devices
3. Discharge exhaust from booths, tents, and hoods
B. General Ventilation
1. Dilution and removal
a. Types of general ventilation systems
b. Ventilation rates
2. Airflow patterns within rooms (air mixing)
3. Airflow direction in the facility
a. Directional airflow
b. Negative pressure for achieving directional airflow
4. Achieving negative pressure in a room
a. Pressure differential
b. Alternate methods for achieving negative pressure
c. Monitoring negative pressure
C. HEPA filtration
1. Use of HEPA filtration when exhausting air to the outside
2. Recirculation of HEPA-filtered air to other areas of a
facility
3. Recirculation of HEPA-filtered air within a room
a. Fixed room-air recirculation systems
b. Portable room-air recirculation units
c. Evaluation of room-air recirculation systems and units
4. Installing, maintaining, and monitoring HEPA filters
D. TB Isolation Rooms and Treatment Rooms
1. Preventing the escape of droplet nuclei from the room
2. Reducing the concentration of droplet nuclei in the room
3. Exhaust from TB isolation rooms and treatment rooms
4. Alternatives to TB isolation rooms
III. UVGI
A. Applications
1. Duct irradiation
2. Upper-room air irradiation
B. Limitations
C. Safety Issues
D. Exposure Criteria for UV Radiation
E. Maintenance and Monitoring
1. Labelling and posting
2. Maintenance
3. Monitoring
Supplement 4: Respiratory Protection
I. Considerations for Selection of Respirators
A. Performance Criteria for Personal Respirators for Protection
Against Transmission of M. tuberculosis
B. Specific Respirators
C. The Effectiveness of Respiratory Protective Devices
1. Face-seal leakage
2. Filter leakage
3. Fit testing
4. Fit checking
5. Reuse of respirators
II. Implementing a Personal Respiratory Protection Program
Supplement 5: Decontamination--Cleaning, Disinfecting, and
Sterilizing of Patient-Care Equipment
References
Glossary
Index
List of Tables
List of Figures
Executive Summary
This document updates and replaces all previously published
guidelines for the prevention of Mycobacterium tuberculosis
transmission in health-care facilities. The purpose of this revision is
to emphasize the importance of (a) the hierarchy of control measures,
including administrative and engineering controls and personal
respiratory protection; (b) the use of risk assessments for developing
a written tuberculosis (TB) control plan; (c) early identification and
management of persons who have TB; (d) TB screening programs for
health-care workers (HCWs); (e) HCW training and education; and (f) the
evaluation of TB infection-control programs.
Transmission of M. tuberculosis is a recognized risk to patients
and HCWs in health-care facilities. Transmission is most likely to
occur from patients who have unrecognized pulmonary or laryngeal TB,
are not on effective anti-TB therapy, and have not been placed in TB
isolation. Several recent TB outbreaks in health-care facilities,
including outbreaks of multidrug-resistant TB, have heightened concern
about nosocomial transmission. Patients who have multidrug-resistant TB
can remain infectious for prolonged periods, which increases the risk
for nosocomial and/or occupational transmission of M. tuberculosis.
Increases in the incidence of TB have been observed in some geographic
areas; these increases are related partially to the high risk for TB
among immunosuppressed persons, particularly those infected with human
immunodeficiency virus (HIV). Transmission of M. tuberculosis to HIV-
infected persons is of particular concern because these persons are at
high risk for developing active TB if they become infected with the
bacteria. Thus, health-care facilities should be particularly alert to
the need for preventing transmission of M. tuberculosis in settings in
which HIV-infected persons work or receive care.
Supervisory responsibility for the TB infection-control program
should be assigned to a designated person or group of persons who
should be given the authority to implement and enforce TB infection-
control policies. An effective TB infection-control program requires
early identification, isolation, and treatment of persons who have
active TB. The primary emphasis of TB infection-control plans in
health-care facilities should be achieving these three goals by the
application of a hierarchy of control measures, including (a) the use
of administrative measures to reduce the risk for exposure to persons
who have infectious TB, (b) the use of engineering controls to prevent
the spread and reduce the concentration of infectious droplet nuclei,
and (c) the use of personal respiratory protective equipment in areas
where there is still a risk for exposure to M. tuberculosis (e.g., TB
isolation rooms). Implementation of a TB infection-control program
requires risk assessment and development of a TB infection-control
plan; early identification, treatment, and isolation of infectious TB
patients; effective engineering controls; an appropriate respiratory
protection program; HCW TB training, education, counseling, and
screening; and evaluation of the program's effectiveness.
Although completely eliminating the risk for transmission of M.
tuberculosis in all health-care facilities may not be possible at the
present time, adherence to these guidelines should reduce the risk to
persons in these settings. Recently, nosocomial TB outbreaks have
demonstrated the substantial morbidity and mortality among patients and
HCWs that have been associated with incomplete implementation of CDC's
Guidelines for Preventing the Transmission of Tuberculosis in Health-
Care Facilities, with Special Focus on HIV-Related Issues published in
1990.* Follow-up investigations at some of these hospitals have
documented that complete implementation of measures similar or
identical to those in the 1990 TB Guidelines significantly reduced or
eliminated nosocomial transmission of M. tuberculosis to patients and/
or HCWs.
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*CDC. Guidelines for Preventing the Transmission of Tuberculosis
in Health-Care Facilities, with Special Focus on HIV-Related Issues.
MMWR 1990; 39 (No. RR-17).
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I. Introduction
A. Purpose of Document
In April 1992, the National MDR-TB Task Force published the
National Action Plan to Combat Multidrug-Resistant Tuberculosis (1).
The publication was a response to reported nosocomial outbreaks of
tuberculosis (TB), including outbreaks of multidrug-resistant TB (MDR-
TB), and the increasing incidence of TB in some geographic areas. The
plan called for the update and revision of the guidelines for
preventing nosocomial transmission of Mycobacterium tuberculosis
published December 7, 1990 (2).
Public meetings were held in October 1992 and January 1993 to
discuss revision of the 1990 TB Guidelines (2). CDC received
considerable input on various aspects of infection control, including
health-care worker (HCW) education; administrative controls (e.g.,
having protocols for the early identification and management of
patients who have TB); the need for more specific recommendations
regarding ventilation; and clarification on the use of respiratory
protection in health-care settings. On the basis of these events and
the input received, on October 12, 1993, CDC published in the Federal
Register the Draft Guidelines For Preventing the Transmission of
Tuberculosis in Health-Care Facilities, Second Edition (3). During and
after the 90-day comment period following publication of this draft,
CDC's TB Infection-Control Guidelines Work Group received and reviewed
more than 2,500 comments.
The purpose of this document is to make recommendations for
reducing the risk for transmitting M. tuberculosis to HCWs, patients,
volunteers, visitors, and other persons in these settings. The
information also may serve as a useful resource for educating HCWs
about TB.
These recommendations update and replace all previously published
CDC recommendations for TB infection control in health-care facilities
(2, 4). The recommendations in this document are applicable primarily
to inpatient facilities in which health care is provided (e.g.,
hospitals, medical wards in correctional facilities, nursing homes, and
hospices). Recommendations applicable to ambulatory-care facilities,
emergency departments, home-health-care settings, emergency medical
services, medical offices, dental settings, and other facilities or
residential settings that provide medical care are provided in separate
sections, with cross-references to other sections of the guidelines if
appropriate.
Designated personnel at health-care facilities should conduct a
risk assessment for the entire facility and for each area* and
occupational group, determine the risk for nosocomial or occupational
transmission of M. tuberculosis, and implement an appropriate TB
infection-control program. The extent of the TB infection-control
program may range from a simple program emphasizing administrative
controls in settings where there is minimal risk for exposure to M.
tuberculosis, to a comprehensive program that includes administrative
controls, engineering controls, and respiratory protection in settings
where the risk for exposure is high. In all settings, administrative
measures should be used to minimize the number of HCWs exposed to M.
tuberculosis while still providing optimal care for TB patients. HCWs
providing care to patients who have TB should be informed about the
level of risk for transmission of M. tuberculosis and the appropriate
control measures to minimize that risk.
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*Area: a structural unit (e.g., a hospital ward or laboratory)
or functional unit (e.g., an internal medicine service) in which
HCWs provide services to and share air with a specific patient
population or work with clinical specimens that may contain viable
M. tuberculosis organisms. The risk for exposure to M. tuberculosis
in a given area depends on the prevalence of TB in the population
served and the characteristics of the environment.
---------------------------------------------------------------------------
In this document, the term ``HCWs'' refers to all the paid and
unpaid persons working in health-care settings who have the potential
for exposure to M. tuberculosis. This may include, but is not limited
to, physicians; nurses; aides; dental workers; technicians; workers in
laboratories and morgues; emergency medical service (EMS) personnel;
students; part-time personnel; temporary staff not employed by the
health-care facility; and persons not involved directly in patient care
but who are potentially at risk for occupational exposure to M.
tuberculosis (e.g., volunteer workers and dietary, housekeeping,
maintenance, clerical, and janitorial staff).
Although the purpose of this document is to make recommendations
for reducing the risk for transmission of M. tuberculosis in health-
care facilities, the process of implementing these recommendations must
safeguard, in accordance with applicable state and federal laws, the
confidentiality and civil rights of persons who have TB.
B. Epidemiology, Transmission, and Pathogenesis of TB
The prevalence of TB is not distributed evenly throughout all
segments of the U.S. population. Some subgroups or persons have a
higher risk for TB either because they are more likely than other
persons in the general population to have been exposed to and infected
with M. tuberculosis or because their infection is more likely to
progress to active TB after they have been infected (5). In some cases,
both of these factors may be present. Groups of persons known to have a
higher prevalence of TB infection include contacts of persons who have
active TB, foreign-born persons from areas of the world with a high
prevalence of TB (e.g., Asia, Africa, the Caribbean, and Latin
America), medically underserved populations (e.g., some African-
Americans, Hispanics, Asians and Pacific Islanders, American Indians,
and Alaskan Natives), homeless persons, current or former correctional-
facility inmates, alcoholics, injecting-drug users, and the elderly.
Groups with a higher risk for progression from latent TB infection to
active disease include persons who have been infected recently (i.e.,
within the previous 2 years), children less than 10% below ideal body weight, chronic renal failure with
renal dialysis, diabetes mellitus, immunosuppression resulting from
receipt of high-dose corticosteroid or other immunosuppressive therapy,
and some malignancies) (5).
M. tuberculosis is carried in airborne particles, or droplet
nuclei, that can be generated when persons who have pulmonary or
laryngeal TB sneeze, cough, speak, or sing (6). The particles are an
estimated 1-5 m in size, and normal air currents can keep them
airborne for prolonged time periods and spread them throughout a room
or building (7). Infection occurs when a susceptible person inhales
droplet nuclei containing M. tuberculosis, and these droplet nuclei
traverse the mouth or nasal passages, upper respiratory tract, and
bronchi to reach the alveoli of the lungs. Once in the alveoli, the
organisms are taken up by alveolar macrophages and spread throughout
the body. Usually within 2-10 weeks after initial infection with M.
tuberculosis, the immune response limits further multiplication and
spread of the tubercle bacilli; however, some of the bacilli remain
dormant and viable for many years. This condition is referred to as
latent TB infection. Persons with latent TB infection usually have
positive purified protein derivative (PPD)-tuberculin skin-test
results, but they do not have symptoms of active TB, and they are not
infectious.
In general, persons who become infected with M. tuberculosis have
approximately a 10% risk for developing active TB during their
lifetimes. This risk is greatest during the first 2 years after
infection. Immunocompromised persons have a greater risk for the
progression of latent TB infection to active TB disease; HIV infection
is the strongest known risk factor for this progression. Persons with
latent TB infection who become coinfected with HIV have approximately
an 8%-10% risk per year for developing active TB (8). HIV-infected
persons who are already severely immunosuppressed and who become newly
infected with M. tuberculosis have an even greater risk for developing
active TB (9-12).
The probability that a person who is exposed to M. tuberculosis
will become infected depends primarily on the concentration of
infectious droplet nuclei in the air and the duration of exposure.
Characteristics of the TB patient that enhance transmission include (a)
disease in the lungs, airways, or larynx; (b) presence of cough or
other forceful expiratory measures; (c) presence of acid-fast bacilli
(AFB) in the sputum; (d) failure of the patient to cover the mouth and
nose when coughing or sneezing; (e) presence of cavitation on chest
radiograph; (f) inappropriate or short duration of chemotherapy; and
(g) administration of procedures that can induce coughing or cause
aerosolization of M. tuberculosis (e.g., sputum induction).
Environmental factors that enhance the likelihood of transmission
include (a) exposure in relatively small, enclosed spaces; (b)
inadequate local or general ventilation that results in insufficient
dilution and/or removal of infectious droplet nuclei; and (c)
recirculation of air containing infectious droplet nuclei.
Characteristics of the persons exposed to M. tuberculosis that may
affect the risk for becoming infected are not as well defined. In
general, persons who have been infected previously with M. tuberculosis
may be less susceptible to subsequent infection. However, reinfection
can occur among previously infected persons, especially if they are
severely immunocompromised. Vaccination with Bacille of Calmette and
Guerin (BCG) probably does not affect the risk for infection; rather,
it decreases the risk for progressing from latent TB infection to
active TB (13). Finally, although it is well established that HIV
infection increases the likelihood of progressing from latent TB
infection to active TB, it is unknown whether HIV infection increases
the risk for becoming infected if exposed to M. tuberculosis.
C. Risk for Nosocomial Transmission of M. Tuberclosis
Transmission of M. tuberclosis is a recognized risk in health-care
facilities (14-22). The magnitude of the risk varies considerably by
the type of health-care facility, the prevalence of TB in the
community, the patient population served, the HCW's occupational group,
the area of the health-care facility in which the HCW works, and the
effectiveness of TB infection-control interventions. The risk may be
higher in areas where patients with TB are provided care before
diagnosis and initiation of TB treatment and isolation precautions
(e.g., in clinic waiting areas and emergency departments) or where
diagnostic or treatment procedures that stimulate coughing are
performed. Nosocomial transmission of M. tuberclosis has been
associated with close contact with persons who have infectious TB and
with the performance of certain procedures (e.g., bronchoscopy [17],
endotracheal intubation and suctioning [18], open abscess irrigation
[20], and autopsy [21,22]). Sputum induction and aerosol treatments
that induce coughing may also increase the potential for transmission
of M. tuberclosis (23,24). Personnel of health-care facilities should
be particularly alert to the need for preventing transmission of M.
tuberclosis in those facilities in which immunocompromised persons
(e.g., HIV-infected persons) work or receive care--especially if cough-
inducing procedures, such as sputum induction and aerosolized
pentamidine treatments, are being performed.
Several TB outbreaks among persons in health-care facilities have
been reported recently (11,24-28; CDC, unpublished data). Many of these
outbreaks involved transmission of multidrug-resistant strains of M.
tuberclosis to both patients and HCWs. Most of the patients and some of
the HCWs were HIV-infected persons in whom new infection progressed
rapidly to active disease. Mortality associated with those outbreaks
was high (range: 43%-93%). Furthermore, the interval between diagnosis
and death was brief (range of median intervals: 4-16 weeks). Factors
contributing to these outbreaks included delayed diagnosis of TB,
delayed recognition of drug resistance, and delayed initiation of
effective therapy--all of which resulted in prolonged infectiousness,
delayed initiation and inadequate duration of TB isolation, inadequate
ventilation in TB isolation rooms, lapses in TB isolation practices and
inadequate precautions for cough-inducing procedures, and lack of
adequate respiratory protection. Analysis of data collected from three
of the health-care facilities involved in the outbreaks indicates that
transmission of M. tuberclosis decreased significantly or ceased
entirely in areas where measures similar to those in the 1990 TB
Guidelines were implemented (2,29-32). However, several interventions
were implemented simultaneously, and the effectiveness of the separate
interventions could not be determined.
D. Fundamentals of TB Infection Control
An effective TB infection-control program requires early
identification, isolation, and effective treatment of persons who have
active TB. The primary emphasis of the TB infection-control plan should
be on achieving these three goals. In all health-care facilities,
particularly those in which persons who are at high risk for TB work or
receive care, policies and procedures for TB control should be
developed, reviewed periodically, and evaluated for effectiveness to
determine the actions necessary to minimize the risk for transmission
of M. tuberclosis.
The TB infection-control program should be based on a hierarchy of
control measures. The first level of the hierarchy, and that which
affects the largest number of persons, is using administrative measures
intended primarily to reduce the risk for exposing uninfected persons
to persons who have infectious TB. These measures include (a)
developing and implementing effective written policies and protocols to
ensure the rapid identification, isolation, diagnostic evaluation, and
treatment of persons likely to have TB; (b) implementing effective work
practices among HCWs in the health-care facility (e.g., correctly
wearing respiratory protection and keeping doors to isolation rooms
closed); (c) educating, training, and counseling HCWs about TB; and (d)
screening HCWs for TB infection and disease.
The second level of the hierarchy is the use of engineering
controls to prevent the spread and reduce the concentration of
infectious droplet nuclei. These controls include (a) direct source
control using local exhaust ventilation, (b) controlling direction of
airflow to prevent contamination of air in areas adjacent to the
infectious source, (c) diluting and removing contaminated air via
general ventilation, and (d) air cleaning via air filtration or
ultraviolet germicidal irradiation (UVGI).
The first two levels of the hierarchy minimize the number of areas
in the health-care facility where exposure to infectious TB may occur,
and they reduce, but do not eliminate, the risk in those few areas
where exposure to M. tuberculosis can still occur (e.g., rooms in which
patients with known or suspected infectious TB are being isolated and
treatment rooms in which cough-inducing or aerosol-generating
procedures are performed on such patients). Because persons entering
such rooms may be exposed to M. tuberculosis, the third level of the
hierarchy is the use of personal respiratory protective equipment in
these and certain other situations in which the risk for infection with
M. tuberculosis may be relatively higher.
Specific measures to reduce the risk for transmission of M.
tuberculosis include the following:
Assigning to specific persons in the health-care facility
the supervisory responsibility for designing, implementing, evaluating,
and maintaining the TB infection-control program (Section II.A).
Conducting a risk assessment to evaluate the risk for
transmission of M. tuberculosis in all areas of the health-care
facility, developing a written TB infection-control program based on
the risk assessment, and periodically repeating the risk assessment to
evaluate the effectiveness of the TB infection-control program (Section
II.B).
Developing, implementing, and enforcing policies and
protocols to ensure early identification, diagnostic evaluation, and
effective treatment of patients who may have infectious TB (Section
II.C; Suppl. 2).
Providing prompt triage for and appropriate management of
patients in the outpatient setting who may have infectious TB (Section
II.D).
Promptly initiating and maintaining TB isolation for
persons who may have infectious TB and who are admitted to the
inpatient setting (Section II.E; Suppl. 1).
Effectively planning arrangements for discharge (Section
II.E).
Developing, installing, maintaining, and evaluating
ventilation and other engineering controls to reduce the potential for
airborne exposure to M. tuberculosis (Section II.F; Suppl. 3).
Developing, implementing, maintaining, and evaluating a
respiratory protection program (Section II.G; Suppl. 4).
Using precautions while performing cough-inducing
procedures (Section II.H; Suppl. 3).
Educating and training HCWs about TB, effective methods
for preventing transmission of M. tuberculosis, and the benefits of
medical screening programs (Section II.I).
Developing and implementing a program for routine periodic
counseling and screening of HCWs for active TB and latent TB infection
(Section II.J; Suppl. 2).
Promptly evaluating possible episodes of M. tuberculosis
transmission in health-care facilities, including PPD skin-test
conversions among HCWs, epidemiologically associated cases among HCWs
or patients, and contacts of patients or HCWs who have TB and who were
not promptly identified and isolated (Section II.K).
Coordinating activities with the local public health
department, emphasizing reporting, and ensuring adequate discharge
follow-up and the continuation and completion of therapy (Section
II.L).
II. Recommendations
A. Assignment of Responsibility
Supervisory responsibility for the TB infection-control
program should be assigned to a designated person or group of persons
with expertise in infection control, occupational health, and
engineering. These persons should be given the authority to implement
and enforce TB infection-control policies.
If supervisory responsibility is assigned to a committee,
one person should be designated as the TB contact person. Questions and
problems can then be addressed to this person.
B. Risk Assessment, Development of the TB Infection-Control Plan, and
Periodic Reassessment
1. Risk Assessment
a. General.
TB infection-control measures for each health-care
facility should be based on a careful assessment of the risk for
transmission of M. tuberculosis in that particular setting. The first
step in developing the TB infection-control program should be to
conduct a baseline risk assessment to evaluate the risk for
transmission of M. tuberculosis in each area and occupational group in
the facility (Table 1, Figure 1). Appropriate infection-control
interventions can then be developed on the basis of actual risk. Risk
assessments should be performed for all inpatient and outpatient
settings (e.g., medical and dental offices).
Regardless of risk level, the management of patients with
known or suspected infectious TB should not vary. However, the index of
suspicion for infectious TB among patients, the frequency of HCW PPD
skin testing, the number of TB isolation rooms, and other factors will
depend on whether the risk for transmission of M. tuberculosis in the
facility, area, or occupational group is high, intermediate, low, very
low, or minimal.
The risk assessment should be conducted by a qualified
person or group of persons (e.g., hospital epidemiologists, infectious
disease specialists, pulmonary disease specialists, infection-control
practitioners, health-care administrators, occupational health
personnel, engineers, HCWs, or local public health personnel).
The risk assessment should be conducted for the entire
facility and for specific areas within the facility (e.g., medical, TB,
pulmonary, or HIV wards; HIV, infectious disease, or pulmonary clinics;
and emergency departments or other areas where TB patients might
receive care or where cough-inducing procedures are performed). This
should include both inpatient and outpatient areas. In addition, risk
assessments should be conducted for groups of HCWs who work throughout
the facility rather than in a specific area (e.g., respiratory
therapists; bronchoscopists; environmental services, dietary, and
maintenance personnel; and students, interns, residents, and fellows).
Classification of risk for a facility, for a specific
area, and for a specific occupational group should be based on (a) the
profile of TB in the community; (b) the number of infectious TB
patients admitted to the area or ward, or the estimated number of
infectious TB patients to whom HCWs in an occupational group may be
exposed; and (c) the results of analysis of HCW PPD test conversions
(where applicable) and possible person-to-person transmission of M.
tuberculosis (Figure 1).
All TB infection-control programs should include periodic
reassessments of risk. The frequency of repeat risk assessments should
be based on the results of the most recent risk assessment (Table 2,
Figure 1).
The ``minimal-risk'' category applies only to an entire
facility. A ``minimal-risk'' facility does not admit TB patients to
inpatient or outpatient areas and is not located in a community with TB
(i.e., counties or communities in which TB cases have not been reported
during the previous year). Thus, there is essentially no risk for
exposure to TB patients in the facility. This category may also apply
to many outpatient settings (e.g., many medical and dental offices).
Table 1. Elements of a Risk Assessment for Tuberculosis (TB) in Health-
care Facilities
1. Review the community TB profile (from public health department
data).
2. Review the number of TB patients who were treated in each area
of the facility (both inpatient and outpatient). (This information can
be obtained by analyzing laboratory surveillance data and by reviewing
discharge diagnoses or medical and infection-control records.)
3. Review the drug-susceptibility patterns of TB isolates of
patients who were treated at the facility.
4. Analyze purified protein derivative (PPD)-tuberculin skin-test
results of health-care workers (HCWs), by area or by occupational group
for HCWs not assigned to specific area (e.g., respiratory therapists).
5. To evaluate infection-control parameters, review medical records
of a sample of TB patients seen at the facility.
Calculate Intervals From
Admission until TB suspected;
Admission until TB evaluation performed;
Admission until acid-fast bacilli (AFB) specimens ordered;
AFB specimens ordered until AFB specimens collected;
AFB specimens collected until AFB smears performed and
reported;
AFB specimens collected until cultures performed and
reported;
AFB specimens collected until species identification
conducted and reported;
AFB specimens collected until drug-susceptibility tests
performed and reported;
Admission until TB isolation initiated;
Admission until TB treatment initiated; and
Duration of TB isolation.
Obtain the Following Additional Information
Were appropriate criteria used for discontinuing
isolation?
Did the patient have a history of prior admission to the
facility?
Was the TB treatment regimen adequate?
Were follow-up sputum specimens collected properly?
Was appropriate discharge planning conducted?
6. Perform an observational review of TB infection control
practices.
7. Review the most recent environmental evaluation and maintenance
procedures.
BILLING CODE 4163-18-P
TN28OC94.000
TN28OC94.001
BILLING CODE 4163-18-C
Table 2.--Elements of a Tuberculosis (TB) Infection-Control Program
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Risk categories
Element ------------------------------------------------------------------------------------------------
Minimal Very low Low Intermediate High
--------------------------------------------------------------------------------------------------------------------------------------------------------
Assigning responsibility (Section II.A)
Designated TB control officer or committee......... R R R R....................... R
Conducting a risk assessment (Section II.B.1)
Baseline risk assessment........................... R R R R....................... R
Community TB profile: incidence, prevalence, and Y Y Y Y....................... Y
drug-susceptibility patterns.
Facility case surveillance (laboratory- and C C C C....................... C
discharge-diagnosis-based).
Analysis of purified protein derivative (PPD) test N/A V* Y Every 6-12 mos.......... Every 3 mos.
results among health-care workers (HCWs).
Review of TB patient medical records............... N/A O Y Every 6-12 mos.......... Every 3 mos.
Observation of infection-control practices......... N/A N/A Y Every 6-12 mos.......... Every 3 mos.
Evaluation of engineering control maintenance...... OSec. OSec. Y Every 6-12 mos.......... Every 3 mos.
Developing a TB infection control plan (Section II.B.2)
Written TB infection control plan.................. R R R R....................... R
Periodically reassessing risk (Section II.B.3)
Reassessment of risk............................... Y Y Y Every 6-12 mos.......... Every 3 mos.
Identifying, evaluating, and initiating treatment for
patients who may have active TB (Section II.C)
Protocol (clinical prediction rules for R R R R....................... R
identifying patients who may have active TB.
Protocol for diagnostic evaluation of patients who N/A R R R....................... R
may have active TB**.
Protocol for reporting laboratory results to N/A R R R....................... R
clinicians, infection-control practitioners,
collaborating referral facilities, and appropriate
health department(s).
Protocol for initiating treatment of patients who N/A R R R....................... R
may have active TB**.
Managing patients who may have TB in ambulatory-care
settings and emergency departments (Section II.D)
Triage system for identifying patients who have R R R R....................... R
active TB in emergency departments and ambulatory-
care settings.
Protocol for managing patients who may have active R R R R....................... R
TB in emergency departments and ambulatory-care
settings.
Protocol for referring patients who may have active R R N/A..... N/A
TB to collaborating facility. a
Managing hospitalized patients who may have TB (Section
II.E)
Appropriate number of TB isolation roomsN/ASecs. .. N/A N/A R R....................... R
Protocol for initiating TB isolation............... N/A N/A R R....................... R
Protocol for TB isolation practices................ N/A N/A R R....................... R
Protocol for discontinuing TB isolation............ N/A N/A R R....................... R
Protocol for discharge planning.................... N/A N/A R R....................... R
Engineering controls (Suppl. 3, Section II.F)
Protocol(s) for maintenance of engineering controls OSec. OSec. R R....................... R
Respiratory protection (Suppl. 4, Section II.G)
Respiratory protection program..................... N/A V* R R....................... R
Cough-inducing and aerosol-generating procedures
(Section II.H)
Protocol(s) for performing cough-inducing or O O R R....................... R
aerosol-generating procedures.
Engineering controls for performing cough-inducing OSec. O R R....................... R
or aerosol-generating procedures.
Educating and Training HCWs (Section II.I)
Educating and training HCWs regarding TB........... R R R R....................... R
Counseling and screening HCWs (Section II.J)
Counseling HCWs regarding TB....................... R R R R....................... R
Protocol for identifying and evaluating HCWs who R R R R....................... R
have signs or symptoms of active TB.
Baseline PPD testing of HCWs....................... O*** R R R....................... R
Routine periodic PPD screening of HCWs for latent N/A V* Y Every 6-12 mos.......... Every 3 mos.
TB infection.
Protocol for evaluating and managing HCWs who have R R R R....................... R
positive PPD tests.
Protocol for managing HCWs who have active TB...... R R R R....................... R
Conducting a problem evaluation (Section II.K)
Protocol for investigating PPD conversions and R R R R....................... R
active TB in HCWs.
Protocol for investigating possible patient-to- R R R R....................... R
patient transmission of Mycobacterium tuberculosis.
Protocol for investigating possible contacts of TB R R R R....................... R
patients who were not diagnosed initially as
having TB and were not placed in isolation.
Coordination with the public health department (Section
II.L)
Effective system for reporting patients who have R R R R....................... R
suspected or confirmed TB to appropriate health
department(s).
--------------------------------------------------------------------------------------------------------------------------------------------------------
R=recommended; Y=yearly; C=continual; N/A=not applicable; O=optional; V=variable.
*Because very low-risk facilities do not admit patients who may have active TB to inpatient areas, most HCWs in such facilities do not need routine
follow-up PPD screening after baseline PPD testing is done. However, those who are involved in the initial assessment and diagnostic evaluation of
patients in the ambulatory-care, emergency, and admitting departments of such facilities or in the outpatient management of patients with active TB
could be exposed potentially to a patient who has active TB. These HCWs may need to receive routine periodic PPD screening. Similarly, these HCWs may
need to be included in a respiratory protection program.
Because very low-risk facilities do not admit patients suspected of having active TB, review of TB patient medical records is not applicable.
However, follow-up of patients who were identified during triage as possibly having active TB and referred to another institution for further
evaluation and management may be useful in evaluating the effectiveness of the triage system.
Sec. Some minimal or very low-risk facilities may elect to use engineering controls (e.g., booths for cough-inducing procedures, portable high-
efficiency particulate [HEPA] filtration units, ultraviolet germicidal irradiation units) in triage/waiting areas. In such situations, appropriate
protocols for maintaining this equipment should be in place, and this maintenance should be evaluated periodically.
The criteria used in clinical prediction rules will probably vary from facility to facility depending on the prevalence of TB in the population served
by the facility and on the clinical, radiographic, and laboratory characteristics of TB patients examined in the facility.
**The protocols should be consistent with CDC/American Thoracic Society recommendations (33).
Protocols for referring patients who require specialized treatment (e.g., patients with multidrug-resistant TB) may be appropriate.
Secs. Based on maximum daily number of patients requiring TB isolation for suspected or confirmed active TB. Isolation rooms should meet the performance
criteria specified in these guidelines.
If such procedures are used in the triage protocol(s) for identifying patients who may have active TB.
***Minimal-risk facilities do not need to maintain an ongoing PPD skin-testing program. However, baseline PPD testing of HCWs may be advisable so that
if an unexpected exposure does occur, conversions can be distinguished from positive PPD test results caused by previous exposures.
The ``very low-risk'' category generally applies only to
an entire facility. A very low-risk facility is one in which (a)
patients with active TB are not admitted to inpatient areas but may
receive initial assessment and diagnostic evaluation or outpatient
management in outpatient areas (e.g., ambulatory-care and emergency
departments) and (b) patients who may have active TB and need inpatient
care are promptly referred to a collaborating facility. In such
facilities, the outpatient areas in which exposure to patients with
active TB could occur should be assessed and assigned to the
appropriate low-, intermediate-, or high-risk category. Categorical
assignment will depend on the number of TB patients examined in the
area during the preceding year and whether there is evidence of
nosocomial transmission of M. tuberculosis in the area. If TB cases
have been reported in the community, but no patients with active TB
have been examined in the outpatient area during the preceding year,
the area can be designated as very low risk (e.g., many medical
offices).
The referring and receiving facilities should establish a referral
agreement to prevent inappropriate management and potential loss to
follow-up of patients suspected of having TB during evaluation in the
triage system of a very low-risk facility.
In some facilities in which TB patients are admitted to inpatient
areas, a very low-risk protocol may be appropriate for areas (e.g.,
administrative areas) or occupational groups that have only a very
remote possibility of exposure to M. tuberculosis.
The very low-risk category may also be appropriate for outpatient
facilities that do not provide initial assessment of persons who may
have TB, but do screen patients for active TB as part of a limited
medical screening before undertaking specialty care (e.g., dental
settings).
``Low-risk'' areas or occupational groups are those in
which (a) the PPD test conversion rate is not greater than that for
areas or groups in which occupational exposure to M. tuberculosis is
unlikely or than previous conversion rates for the same area or group,
(b) no clusters* of PPD test conversions have occurred, (c) person-to-
person transmission of M. tuberculosis has not been detected, and (d)
fewer than six TB patients are examined or treated per year.
---------------------------------------------------------------------------
*Cluster: two or more PPD skin-test conversions occurring within
a 3-month period among HCWs in a specific area or occupational
group, and epidemiologic evidence suggests occupational (nosocomial)
transmission.
---------------------------------------------------------------------------
``Intermediate-risk'' areas or occupational groups are
those in which (a) the PPD test conversion rate is not greater than
that for areas or groups in which occupational exposure to M.
tuberculosis is unlikely or than previous conversion rates for the same
area or group, (b) no clusters of PPD test conversions have occurred,
(c) person-to-person transmission of M. tuberculosis) has not been
detected, and (d) six or more patients with active TB are examined or
treated each year. Survey data suggest that facilities in which six or
more TB patients are examined or treated each year may have an
increased risk for transmission of M. tuberculosis (CDC, unpublished
data); thus, areas in which six or more patients with active TB are
examined or treated each year (or occupational groups in which HCWs are
likely to be exposed to six or more TB patients per year) should be
classified as ``intermediate risk.''
``High-risk'' areas or occupational groups are those in
which (a) the PPD test conversion rate is significantly greater than
for areas or groups in which occupational exposure to M. tuberculosis
is unlikely or than previous conversion rates for the same area or
group, and epidemiologic evaluation suggests nosocomial transmission;
or (b) a cluster of PPD test conversions has occurred, and
epidemiologic evaluation suggests nosocomial transmission of M.
tuberculosis; or (c) possible person-to-person transmission of M.
tuberculosis has been detected.
If no data or insufficient data for adequate determination
of risk have been collected, such data should be compiled, analyzed,
and reviewed expeditiously.
b. Community TB profile.
A profile of TB in the community that is served by the
facility should be obtained from the public health department. This
profile should include, at a minimum, the incidence (and prevalence, if
available) of active TB in the community and the drug-susceptibility
patterns of M. tuberculosis isolates (i.e., the antituberculous agents
to which each isolate is susceptible and those to which it is
resistant) from patients in the community.
c. Case surveillance.
Data concerning the number of suspected and confirmed
active TB cases among patients and HCWs in the facility should be
systematically collected, reviewed, and used to estimate the number of
TB isolation rooms needed, to recognize possible clusters of nosocomial
transmission, and to assess the level of potential occupational risk.
The number of TB patients in specific areas of a facility can be
obtained from laboratory surveillance data on specimens positive for
AFB smears or M. tuberculosis cultures, from infection-control records,
and from databases containing information about hospital discharge
diagnoses.
Drug-susceptibility patterns of M. tuberculosis isolates
from TB patients treated in the facility should be reviewed to identify
the frequency and patterns of drug resistance. This information may
indicate a need to modify the initial treatment regimen or may suggest
possible nosocomial transmission or increased occupational risk.
d. Analysis of HCW PPD test screening data.
Results of HCW PPD testing should be recorded in the
individual HCW's employee health record and in a retrievable aggregate
database of all HCW PPD test results. Personal identifying information
should be handled confidentially. PPD test conversion rates should be
calculated at appropriate intervals to estimate the risk for PPD test
conversions for each area of the facility and for each specific
occupational group not assigned to a specific area (Table 2). To
calculate PPD test conversion rates, the total number of previously
PPD-negative HCWs tested in each area or group (i.e., the denominator)
and the number of PPD test conversions among HCWs in each area or group
(the numerator) must be obtained.
PPD test conversion rates for each area or occupational
group should be compared with rates for areas or groups in which
occupational exposure to M. tuberculosis is unlikely and with previous
conversion rates in the same area or group to identify areas or groups
where the risk for occupational PPD test conversions may be increased.
A low number of HCWs in a specific area may result in a greatly
increased rate of conversion for that area, although the actual risk
may not be significantly greater than that for other areas. Testing for
statistical significance (e.g., Fisher's exact test or chi square test)
may assist interpretation; however, lack of statistical significance
may not rule out a problem (i.e., if the number of HCWs tested is low,
there may not be adequate statistical power to detect a significant
difference). Thus, interpretation of individual situations is
necessary.
An epidemiologic investigation to evaluate the likelihood
of nosocomial transmission should be conducted if PPD test conversions
are noted (Section II.K.1).
The frequency and comprehensiveness of the HCW PPD testing
program should be evaluated periodically to ensure that all HCWs who
should be included in the program are being tested at appropriate
intervals. For surveillance purposes, earlier detection of transmission
may be enhanced if HCWs in a given area or occupational group are
tested on different scheduled dates rather than all being tested on the
same date (Section II.J.3).
e. Review of TB patient medical records.
The medical records of a sample of TB patients examined at
the facility can be reviewed periodically to evaluate infection-control
parameters (Table 1). Parameters to examine may include the intervals
from date of admission until (a) TB was suspected, (b) specimens for
AFB smears were ordered, (c) these specimens were collected, (d) tests
were performed, and (e) results were reported. Moreover, the adequacy
of the TB treatment regimens that were used should be evaluated.
Medical record reviews should note previous hospital
admissions of TB patients before the onset of TB symptoms. Patient-to-
patient transmission may be suspected if active TB occurs in a patient
who had a prior hospitalization during which exposure to another TB
patient occurred or if isolates from two or more TB patients have
identical characteristic drug-susceptibility or DNA fingerprint
patterns.
Data from the case review should be used to determine if
there is a need to modify (a) protocols for identifying and isolating
patients who may have infectious TB, (b) laboratory procedures, (c)
administrative policies and practices, or (d) protocols for patient
management.
f. Observation of TB infection-control practices.
Assessing adherence to the policies of the TB infection-
control program should be part of the evaluation process. This
assessment should be performed on a regular basis and whenever an
increase occurs in the number of TB patients or HCW PPD test
conversions. Areas at high risk for transmission of M. tuberculosis
should be monitored more frequently than other areas. The review of
patient medical records provides information on HCW adherence to some
of the policies of the TB infection-control program. In addition, work
practices related to TB isolation (e.g., keeping doors to isolation
rooms closed) should be observed to determine if employers are
enforcing, and HCWs are adhering to, these policies and if patient
adherence is being enforced. If these policies are not being enforced
or adhered to, appropriate education and other corrective action should
be implemented.
g. Engineering evaluation
Results of engineering maintenance measures should be
reviewed at regular intervals (Table 3). Data from the most recent
evaluation and from maintenance procedures and logs should be reviewed
carefully as part of the risk assessment.
2. Development of the TB Infection-Control Plan
Based on the results of the risk assessment, a written TB
infection-control plan should be developed and implemented for each
area of the facility and for each occupational group of HCWs not
assigned to a specific area of the facility (Table 2; Table 3).
The occurrence of drug-resistant TB in the facility or the
community, or a relatively high prevalence of HIV infection among
patients or HCWs in the community, may increase the concern about
transmission of M. tuberculosis and may influence the decision
regarding which protocol to follow (i.e., a higher-risk classification
may be selected).
Health-care facilities are likely to have a combination of
low-, intermediate-, and high-risk areas or occupational groups during
the same time period. The appropriate protocol should be implemented
for each area or group.
Areas in which cough-inducing procedures are performed on
patients who may have active TB should, at the minimum, implement the
intermediate-risk protocol.
3. Periodic Reassessment
Follow-up risk assessment should be performed at the
interval indicated by the most recent risk assessment (Figure 1; Table
2). Based on the results of the follow-up assessment, problem
evaluation may need to be conducted or the protocol may need to be
modified to a higher- or lower-risk level.
Table 3. Characteristics of an Effective Tuberculosis (TB) Infection-
Control Program*
I. Assignment of responsibility
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*A program such as this is appropriate for health-care
facilities in which there is a high risk for transmission of
Mycobacterium tuberculosis.
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A. Assign responsibility for the TB infection-control program to
qualified person(s).
B. Ensure that persons with expertise in infection control,
occupational health, and engineering are identified and included.
II. Risk assessment, TB infection-control plan, and periodic
reassessment
A. Initial risk assessments
1. Obtain information concerning TB in the community.
2. Evaluate data concerning TB patients in the facility.
3. Evaluate data concerning purified protein derivative (PPD)-
tuberculin skin-test conversions among health-care workers (HCWs) in
the facility.
4. Rule out evidence of person-to-person transmission.
B. Written TB infection-control program
1. Select initial risk protocol(s).
2. Develop written TB infection-control protocols.
C. Repeat risk assessment at appropriate intervals.
1. Review current community and facility surveillance data and PPD-
tuberculin skin-test results.
2. Review records of TB patients.
3. Observe HCW infection-control practices.
4. Evaluate maintenance of engineering controls.
III. Identification, evaluation, and treatment of patients who have TB
A. Screen patients for signs and symptoms of active TB:
1. On initial encounter in emergency department or ambulatory-care
setting.
2. Before or at the time of admission.
B. Perform radiologic and bacteriologic evaluation of patients who
have signs and symptoms suggestive of TB.
C. Promptly initiate treatment.
IV. Managing outpatients who have possible infectious TB
A. Promptly initiate TB precautions.
B. Place patients in separate waiting areas or TB isolation rooms.
C. Give patients a surgical mask, a box of tissues, and
instructions regarding the use of these items.
V. Managing inpatients who have possible infectious TB
A. Promptly isolate patients who have suspected or known infectious
TB.
B. Monitor the response to treatment.
C. Follow appropriate criteria for discontinuing isolation.
VI. Engineering recommendations
A. Design local exhaust and general ventilation in collaboration
with persons who have expertise in ventilation engineering.
B. Use a single-pass air system or air recirculation after high-
efficiency particulate air (HEPA) filtration in areas where infectious
TB patients receive care.
C. Use additional measures, if needed, in areas where TB patients
may receive care.
D. Design TB isolation rooms in health-care facilities to achieve
6 air changes per hour (ACH) for existing facilities and
12 ACH for new or renovated facilities.
E. Regularly monitor and maintain engineering controls.
F. TB isolation rooms that are being used should be monitored daily
to ensure they maintain negative pressure relative to the hallway and
all surrounding areas.
G. Exhaust TB isolation room air to outside or, if absolutely
unavoidable, recirculate after HEPA filtration.
VII. Respiratory protection
A. Respiratory protective devices should meet recommended
performance criteria.
B. Respiratory protection should be used by persons entering rooms
in which patients with known or suspected infectious TB are being
isolated, by HCWs when performing cough-inducing or aerosol-generating
procedures on such patients, and by persons in other settings where
administrative and engineering controls are not likely to protect them
from inhaling infectious airborne droplet nuclei.
C. A respiratory protection program is required at all facilities
in which respiratory protection is used.
VIII. Cough-inducing procedures
A. Do not perform such procedures on TB patients unless absolutely
necessary.
B. Perform such procedures in areas that have local exhaust
ventilation devices (e.g., booths or special enclosures) or, if this is
not feasible, in a room that meets the ventilation requirements for TB
isolation.
C. After completion of procedures, TB patients should remain in the
booth or special enclosure until their coughing subsidies.
IX. HCW TB training and education
A. All HCWs should receive periodic TB education appropriate for
their work responsibilities and duties.
B. Training should include the epidemiology of TB in the facility.
C. TB education should emphasize concepts of the pathogenesis of
and occupational risk for TB.
D. Training should describe work practices that reduce the
likelihood of transmitting M. tuberculosis.
X. HCW counseling and screening
A. Counsel all HCWs regarding TB and TB infection.
B. Counsel all HCWs about the increased risk to immunocompromised
persons for developing active TB.
C. Perform PPD skin tests on HCWs at the beginning of their
employment, and repeat PPD tests at periodic intervals.
D. Evaluate symptomatic HCWs for active TB.
XI. Evaluate HCW PPD test conversions and possible nosocomial
transmission of M. tuberculosis.
XII. Coordinate efforts with public health department(s)
After each risk assessment, the staff responsible for TB
control, in conjunction with other appropriate HCWs, should review all
TB control policies to ensure that they are effective and meet current
needs.
4. Examples of Risk Assessment
Examples of six hypothetical situations and the means by which
surveillance data are used to select a TB control protocol are
described as follows:
Hospital A. The overall HCW PPD test conversion rate in the
facility is 1.6%. No areas or HCW occupational groups have a
significantly greater PPD test conversion rate than areas or groups in
which occupational exposure to M. tuberculosis is unlikely (or than
previous rates for the same area or group). No clusters of PPD test
conversions have occurred. Patient-to-patient transmission has not been
detected. Patients who have TB are admitted to the facility, but no
area admits six or more TB patients per year. The low-risk protocol
will be followed in all areas.
Hospital B. The overall HCW PPD test conversion rate in the
facility is 1.8%. The PPD test conversion rate for the medical
intensive-care unit rate is significantly higher than all other areas
in the facility. The problem identification process is initiated
(Section II.K). It is determined that all TB patients have been
isolated appropriately. Other potential problems are then evaluated,
and the cause for the higher rate is not identified. After consulting
the public health department TB infection-control program, the high-
risk protocol is followed in the unit until the PPD test conversion
rate is similar to areas of the facility in which occupational exposure
to TB patients is unlikely. If the rate remains significantly higher
than other areas, further evaluation, including environmental and
procedural studies, will be performed to identify possible reasons for
the high conversion rate.
Hospital C. The overall HCW PPD test conversion rate in the
facility is 2.4%. Rates range from 0 to 2.6% for the individual areas
and occupational groups. None of these rates is significantly higher
than rates for areas in which occupational exposure to M. tuberculosis
is unlikely. No particular HCW group has higher conversion rates than
the other groups. No clusters of HCW PPD test conversions have
occurred. In two of the areas, HCWs cared for more than six TB patients
during the preceding year. These two areas will follow the
intermediate-risk protocol, and all other areas will follow the low-
risk protocol. This hospital is located in the southeastern United
States, and these conversion rates may reflect cross-reactivity with
nontuberculous mycobacteria.
Hospital D. The overall HCW PPD test conversion rate in the
facility is 1.2%. In no area did HCWs care for six or more TB patients
during the preceding year. Three of the 20 respiratory therapists
tested had PPD conversions, for a rate of 15%. The respiratory
therapists who had PPD test conversions had spent all or part of their
time in the pulmonary function laboratory, where induced sputum
specimens were obtained. A low-risk protocol is maintained for all
areas and occupational groups in the facility except for respiratory
therapists. A problem evaluation is conducted in the pulmonary function
laboratory (Section II.K). It is determined that the ventilation in
this area is inadequate. Booths are installed for sputum induction. PPD
testing and the risk assessment are repeated 3 months later. If the
repeat testing at 3 months indicates that no more conversions have
occurred, the respiratory therapists will return to the low-risk
protocol.
Hospital E. Hospital E is located in a community that has a
relatively low incidence of TB. To optimize TB services in the
community, the four hospitals in the community have developed an
agreement that one of them (e.g., Hospital G) will provide all
inpatient services to persons who have suspected or confirmed TB. The
other hospitals have implemented protocols in their ambulatory-care
clinics and emergency departments to identify patients who may have
active TB. These patients are then transferred to Hospital G for
inpatient care if such care is considered necessary. After discharge
from Hospital G, they receive follow-up care in the public health
department's TB clinic. During the preceding year, Hospital E has
identified fewer than six TB patients in its ambulatory-care and
emergency departments and has had no PPD test conversions or other
evidence of M. tuberculosis transmission among HCWs or patients in
these areas. These areas are classified as low risk, and all other
areas are classified as very low risk.
Hospital F. Hospital F is located in a county in which no TB cases
have been reported during the preceding 2 years. A risk assessment
conducted at the facility did not identify any patients who had
suspected or confirmed TB during the preceding year. The facility is
classified as minimal risk.
C. Identifying, Evaluating, and Initiating Treatment for Patients Who
May Have Active TB
The most important factors in preventing transmission of M.
tuberculosis are the early identification of patients who may have
infectious TB, prompt implementation of TB precautions for such
patients, and prompt initiation of effective treatment for those who
are likely to have TB.
1. Identifying Patients Who May Have Active TB
Health-care personnel who are assigned responsibility for
TB infection control in ambulatory-care and inpatient settings should
develop, implement, and enforce protocols for the early identification
of patients who may have infectious TB.
The criteria used in these protocols should be based on
the prevalence and characteristics of TB in the population served by
the specific facility. These protocols should be evaluated periodically
and revised according to the results of the evaluation. Review of
medical records of patients who were examined in the facility and
diagnosed as having TB may serve as a guide for developing or revising
these protocols.
A diagnosis of TB may be considered for any patient who
has a persistent cough (i.e., a cough lasting for 3 weeks)
or other signs or symptoms compatible with active TB (e.g., bloody
sputum, night sweats, weight loss, anorexia, or fever). However, the
index of suspicion for TB will vary in different geographic areas and
will depend on the prevalence of TB and other characteristics of the
population served by the facility. The index of suspicion for TB should
be very high in geographic areas or among groups of patients in which
the prevalence of TB is high (Section I.B). Appropriate diagnostic
measures should be conducted and TB precautions implemented for
patients in whom active TB is suspected.
2. Diagnostic Evaluation for Active TB
Diagnostic measures for identifying TB should be conducted
for patients in whom active TB is being considered. These measures
include obtaining a medical history and performing a physical
examination, PPD skin test, chest radiograph, and microscopic
examination and culture of sputum or other appropriate specimens
(6,34,35). Other diagnostic procedures (e.g., bronchoscopy or biopsy)
may be indicated for some patients (36,37).
Prompt laboratory results are crucial to the proper
treatment of the TB patient and to early initiation of infection
control. To ensure timely results, laboratories performing
mycobacteriologic tests should be proficient at both the laboratory and
administrative aspects of specimen processing. Laboratories should use
the most rapid methods available (e.g., fluorescent microscopy for AFB
smears; radiometric culture methods for isolation of mycobacteria;
-nitro--acetylamino--hydroxy-proprophenone
[NAP] test, nucleic acid probes, or high-pressure liquid chromatography
[HPLC] for species identification; and radiometric methods for drug-
susceptibility testing). As other more rapid or sensitive tests become
available, practical, and affordable, such tests should be incorporated
promptly into the mycobacteriology laboratory. Laboratories that rarely
receive specimens for mycobacteriologic analysis should refer the
specimens to a laboratory that more frequently performs these tests.
Results of AFB sputum smears should be available within 24
hours of specimen collection (38).
The probability of TB is greater among patients who have
positive PPD test results or a history of positive PPD test results,
who have previously had TB or have been exposed to M. tuberculosis, or
who belong to a group at high risk for TB (Section I.B). Active TB is
strongly suggested if the diagnostic evaluation reveals AFB in sputum,
a chest radiograph suggestive of TB, or symptoms highly suggestive of
TB. TB can occur simultaneously in immunosuppressed persons who have
pulmonary infections caused by other organisms (e.g., Pneumocystis
carinii or Mycobacterium avium complex) and should be considered in the
diagnostic evaluation of all patients who have symptoms compatible with
TB (Suppl. 1; Suppl. 2).
TB may be more difficult to diagnose among persons who
have HIV infection (or other conditions associated with severe
suppression of cell-mediated immunity) because of a nonclassical
clinical or radiographic presentation and/or the simultaneous
occurrence of other pulmonary infections (e.g., P. carinii pneumonia
and M. avium complex). The difficulty in diagnosing TB in HIV-infected
persons may be further compounded by impaired responses to PPD skin
tests (39,40), the possibly lower sensitivity of sputum smears for
detecting AFB (41), or the overgrowth of cultures with M. avium complex
in specimens from patients infected with both M. avium complex and M.
tuberculosis (42).
Immunosuppressed patients who have pulmonary signs or
symptoms that are ascribed initially to infections or conditions other
than TB should be evaluated initially for coexisting TB. The evaluation
for TB should be repeated if the patient does not respond to
appropriate therapy for the presumed cause(s) of the pulmonary
abnormalities (Suppl. 1; Suppl. 2).
Patients with suspected or confirmed TB should be reported
immediately to the appropriate public health department so that
standard procedures for identifying and evaluating TB contacts can be
initiated.
3. Initiation of Treatment for Suspected or Confirmed TB
Patients who have confirmed active TB or who are
considered highly likely to have active TB should be started promptly
on appropriate treatment in accordance with current guidelines (Suppl.
2) (43). In geographic areas or facilities that have a high prevalence
of MDR-TB, the initial regimen used may need to be enhanced while the
results of drug-susceptibility tests are pending. The decision should
be based on analysis of surveillance data.
While the patient is in the health-care facility, anti-TB
drugs should be administered by directly observed therapy (DOT), the
process by which an HCW observes the patient swallowing the
medications. Continuing DOT after the patient is discharged should be
strongly considered. This decision and the arrangements for providing
outpatient DOT should be made in collaboration with the public health
department.
D. Management of Patients Who May Have Active TB in Ambulatory-Care
Settings and Emergency Departments
Triage of patients in ambulatory-care settings and
emergency departments should include vigorous efforts to promptly
identify patients who have active TB. HCWs who are the first points of
contact in facilities that serve populations at risk for TB should be
trained to ask questions that will facilitate identification of
patients with signs and symptoms suggestive of TB.
Patients with signs or symptoms suggestive of TB should be
evaluated promptly to minimize the amount of time they are in
ambulatory-care areas. TB precautions should be followed while the
diagnostic evaluation is being conducted for these patients.
TB precautions in the ambulatory-care setting should
include (a) placing these patients in a separate area apart from other
patients, and not in open waiting areas (ideally, in a room or
enclosure meeting TB isolation requirements); (b) giving these patients
surgical masks* to wear and instructing them to keep their masks on;
and (c) giving these patients tissues and instructing them to cover
their mouths and noses with the tissues when coughing or sneezing.
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*Surgical masks are designed to prevent the respiratory
secretions of the person wearing the mask from entering the air.
When not in a TB isolation room, patients suspected of having TB
should wear surgical masks to reduce the expulsion of droplet nuclei
into the air. These patients do not need to wear particulate
respirators, which are designed to filter the air before it is
inhaled by the person wearing the mask. Patients suspected of having
or known to have TB should never wear a respirator that has an
exhalation valve, because the device would provide no barrier to the
expulsion of droplet nuclei into the air.
---------------------------------------------------------------------------
TB precautions should be followed for patients who are
known to have active TB and who have not completed therapy until a
determination has been made that they are noninfectious (Suppl. 1).
Patients with active TB who need to attend a health-care
clinic should have appointments scheduled to avoid exposing HIV-
infected or otherwise severely immunocompromised persons to M.
tuberculosis. This recommendation could be accomplished by designating
certain times of the day for appointments for these patients or by
treating them in areas where immunocompromised persons are not treated.
Ventilation in ambulatory-care areas where patients at
high risk for TB are treated should be designed and maintained to
reduce the risk for transmission of M. tuberculosis. General-use areas
(e.g., waiting rooms) and special areas (e.g., treatment or TB
isolation rooms in ambulatory areas) should be ventilated in the same
manner as described for similar inpatient areas (Sections II.E.3, II.F;
Suppl. 3). Enhanced general ventilation or the use of air-disinfection
techniques (e.g., UVGI or recirculation of air within the room through
high-efficiency particulate air [HEPA] filters) may be useful in
general-use areas of facilities where many infectious TB patients
receive care (Section II.F; Suppl. 3).
Ideally, ambulatory-care settings in which patients with
TB are frequently examined or treated should have a TB isolation
room(s) available. Such rooms are not necessary in ambulatory-care
settings in which patients who have confirmed or suspected TB are seen
infrequently. However, these facilities should have a written protocol
for early identification of patients with TB symptoms and referral to
an area or a collaborating facility where the patient can be evaluated
and managed appropriately. These protocols should be reviewed on a
regular basis and revised as necessary. The additional guidelines in
Section II.H should be followed in ambulatory-care settings where
cough-inducing procedures are performed on patients who may have active
TB.
E. Management of Hospitalized Patients Who Have Confirmed or Suspected
TB
1. Initiation of Isolation for TB
In hospitals and other inpatient facilities, any patient
suspected of having or known to have infectious TB should be placed in
a TB isolation room that has currently recommended ventilation
characteristics (Section II.E.3; Suppl. 3). Written policies for
initiating isolation should specify (a) the indications for isolation,
(b) the person(s) authorized to initiate and discontinue isolation, (c)
the isolation practices to follow, (d) the monitoring of isolation, (e)
the management of patients who do not adhere to isolation practices,
and (f) the criteria for discontinuing isolation.
In rare circumstances, placing more than one TB patient
together in the same room may be acceptable. This practice is sometimes
referred to as ``cohorting.'' Because of the risk for patients becoming
superinfected with drug-resistant organisms, patients with TB should be
placed in the same room only if all patients involved (a) have culture-
confirmed TB, (b) have drug-susceptibility test results available on a
current specimen obtained during the present hospitalization, (c) have
identical drug-susceptibility patterns on these specimens, and (d) are
on effective therapy. Having isolates with identical DNA fingerprint
patterns is not adequate evidence for placing two TB patients together
in the same room, because isolates with the same DNA fingerprint
pattern can have different drug-susceptibility patterns.
Pediatric patients with suspected or confirmed TB should
be evaluated for potential infectiousness according to the same
criteria as are adults (i.e., on the basis of symptoms, sputum AFB
smears, radiologic findings, and other criteria) (Suppl. 1). Children
who may be infectious should be placed in isolation until they are
determined to be noninfectious. Pediatric patients who may be
infectious include those who have laryngeal or extensive pulmonary
involvement, pronounced cough, positive sputum AFB smears, or cavitary
TB or those for whom cough-inducing procedures are performed (44).
The source of infection for a child with TB is often a
member of the child's family (45). Therefore, parents and other
visitors of all pediatric TB patients should be evaluated for TB as
soon as possible. Until they have been evaluated, or the source case is
identified, they should wear surgical masks when in areas of the
facility outside of the child's room, and they should refrain from
visiting common areas in the facility (e.g., the cafeteria or lounge
areas).
TB patients in intensive-care units should be treated the
same as patients in noncritical-care settings. They should be placed in
TB isolation and have respiratory secretions submitted for AFB smear
and culture if they have undiagnosed pulmonary symptoms suggestive of
TB.
If readmitted to a health-care facility, patients who are
known to have active TB and who have not completed therapy should have
TB precautions applied until a determination has been made that they
are noninfectious (Suppl. 1).
2. TB Isolation Practices
Patients who are placed in TB isolation should be educated
about the mechanisms of M. tuberculosis transmission and the reasons
for their being placed in isolation. They should be taught to cover
their mouths and noses with a tissue when coughing or sneezing, even
while in the isolation room, to contain liquid drops and droplets
before they are expelled into the air (46).
Efforts should be made to facilitate patient adherence to
isolation measures (e.g., staying in the TB isolation room). Such
efforts might include the use of incentives (e.g., providing them with
telephones, televisions, or radios in their rooms or allowing special
dietary requests). Efforts should also be made to address other
problems that could interfere with adherence to isolation (e.g.,
management of the patient's withdrawal from addictive substances
[including tobacco]).
Patients placed in isolation should remain in their
isolation rooms with the door closed. If possible, diagnostic and
treatment procedures should be performed in the isolation rooms to
avoid transporting patients through other areas of the facility. If
patients who may have infectious TB must be transported outside their
isolation rooms for medically essential procedures that cannot be
performed in the isolation rooms, they should wear surgical masks that
cover their mouths and noses during transport. Persons transporting the
patients do not need to wear respiratory protection outside the TB
isolation rooms. Procedures for these patients should be scheduled at
times when they can be performed rapidly and when waiting areas are
less crowded.
Treatment and procedure rooms in which patients who have
infectious TB or who have an undiagnosed pulmonary disease and are at
high risk for active TB receive care should meet the ventilation
recommendations for isolation rooms (Section II.E.3; Suppl. 3).
Ideally, facilities in which TB patients are frequently treated should
have an area in the radiology department that is ventilated separately
for TB patients. If this is not possible, TB patients should wear
surgical masks and should stay in the radiology suite the minimum
amount of time possible, then be returned promptly to their isolation
rooms.
The number of persons entering an isolation room should be
minimal. All persons who enter an isolation room should wear
respiratory protection (Section II.G; Suppl. 4). The patient's visitors
should be given respirators to wear while in the isolation room, and
they should be given general instructions on how to use their
respirators.
Disposable items contaminated with respiratory secretions
are not associated with transmission of M. tuberculosis. However, for
general infection-control purposes, these items should be handled and
transported in a manner that reduces the risk for transmitting other
microorganisms to patients, HCWs, and visitors and that decreases
environmental contamination in the health-care facility. Such items
should be disposed of in accordance with hospital policy and applicable
regulations (Suppl. 5).
3. The TB Isolation Room
TB isolation rooms should be single-patient rooms with
special ventilation characteristics appropriate for the purposes of
isolation (Suppl. 3). The primary purposes of TB isolation rooms are to
(a) separate patients who are likely to have infectious TB from other
persons; (b) provide an environment that will allow reduction of the
concentration of droplet nuclei through various engineering methods;
and (c) prevent the escape of droplet nuclei from the TB isolation room
and treatment room, thus preventing entry of M. tuberculosis into the
corridor and other areas of the facility.
To prevent the escape of droplet nuclei, the TB isolation
room should be maintained under negative pressure (Suppl. 3). Doors to
isolation rooms should be kept closed, except when patients or
personnel must enter or exit the room, so that negative pressure can be
maintained.
Negative pressure in the room should be monitored daily
while the room is being used for TB isolation.
The American Society of Heating, Refrigerating and Air-
Conditioning Engineers, Inc. (ASHRAE) (47), the American Institute of
Architects (AIA) (48), and the Health Resources and Services
Administration (49) recommend a minimum of 6 air changes per hour (ACH)
for TB isolation and treatment rooms. This ventilation rate is based on
comfort and odor control considerations. The effectiveness of this
level of airflow in reducing the concentration of droplet nuclei in the
room, thus reducing the transmission of airborne pathogens, has not
been evaluated directly or adequately.
Ventilation rates of >6 ACH are likely to produce an incrementally
greater reduction in the concentration of bacteria in a room than are
lower rates (50-52). However, accurate quantitation of decreases in
risk that would result from specific increases in general ventilation
levels has not been performed and may not be possible.
For the purposes of reducing the concentration of droplet nuclei,
TB isolation and treatment rooms in existing health-care facilities
should have an airflow of 6 ACH. Where feasible, this
airflow rate should be increased to 12 ACH by adjusting or
modifying the ventilation system or by using auxiliary means (e.g.,
recirculation of air through fixed HEPA filtration systems or portable
air cleaners) (Suppl. 3, Section II.B.5.a) (53). New construction or
renovation of existing health-care facilities should be designed so
that TB isolation rooms achieve an airflow of 12 ACH.
Air from TB isolation rooms and treatment rooms used to
treat patients who have known or suspected infectious TB should be
exhausted to the outside in accordance with applicable federal, state,
and local regulations. The air should not be recirculated into the
general ventilation. In some instances, recirculation of air into the
general ventilation system from such rooms is unavoidable (i.e., in
existing facilities in which the ventilation system or facility
configuration makes venting the exhaust to the outside impossible). In
such cases, HEPA filters should be installed in the exhaust duct
leading from the room to the general ventilation system to remove
infectious organisms and particulates the size of droplet nuclei from
the air before it is returned to the general ventilation system
(Section II.F; Suppl. 3). Air from TB isolation and treatment rooms in
new or renovated facilities should not be recirculated into the general
ventilation system.
Although not required, an anteroom may increase the
effectiveness of the isolation room by minimizing the potential escape
of droplet nuclei into the corridor when the door is opened. To work
effectively, the anteroom should have positive air pressure in relation
to the isolation room. The pressure relationship between the anteroom
and the corridor may vary according to ventilation design.
Upper-room air UVGI may be used as an adjunct to general
ventilation in the isolation room (Section II.F; Suppl. 3). Air in the
isolation room may be recirculated within the room through HEPA filters
or UVGI devices to increase the effective ACH and to increase thermal
efficiency.
Health-care facilities should have enough isolation rooms
to appropriately isolate all patients who have suspected or confirmed
active TB. This number should be estimated using the results of the
risk assessment of the health-care facility. Except for minimal-and
very low-risk health-care facilities, all acute-care inpatient
facilities should have at least one TB isolation room (Section II.B).
Grouping isolation rooms together in one area of the
facility may reduce the possibility of transmitting M. tuberculosis to
other patients and may facilitate care of TB patients and the
installation and maintenance of optimal engineering (particularly
ventilation) controls.
4. Discontinuation of TB Isolation
TB isolation can be discontinued if the diagnosis of TB is
ruled out. For some patients, TB can be ruled out when another
diagnosis is confirmed. If a diagnosis of TB cannot be ruled out, the
patient should remain in isolation until a determination has been made
that the patient is noninfectious. However, patients can be discharged
from the health-care facility while still potentially infectious if
appropriate postdischarge arrangements can be ensured (Section II.E.5).
The length of time required for a TB patient to become
noninfectious after starting anti-TB therapy varies considerably
(Suppl. 1). Isolation should be discontinued only when the patient is
on effective therapy, is improving clinically, and has had three
consecutive negative sputum AFB smears collected on different days.
Hospitalized patients who have active TB should be
monitored for relapse by having sputum AFB smears examined regularly
(e.g., every 2 weeks). Nonadherence to therapy (i.e., failure to take
medications as prescribed) and the presence of drug-resistant organisms
are the two most common reasons why patients remain infectious despite
treatment. These reasons should be considered if a patient does not
respond clinically to therapy within 2-3 weeks.
Continued isolation throughout the hospitalization should
be strongly considered for patients who have MDR-TB because of the
tendency for treatment failure or relapse (i.e., difficulty in
maintaining noninfectiousness) that has been observed in such cases.
5. Discharge Planning
Before a TB patient is discharged from the health-care
facility, the facility's staff and public health authorities should
collaborate to ensure continuation of therapy. Discharge planning in
the health-care facility should include, at a minimum, (a) a confirmed
outpatient appointment with the provider who will manage the patient
until the patient is cured, (b) sufficient medication to take until the
outpatient appointment, and (c) placement into case management (e.g.,
DOT) or outreach programs of the public health department. These plans
should be initiated and in place before the patient's discharge.
Patients who may be infectious at the time of discharge
should only be discharged to facilities that have isolation capability
or to their homes. Plans for discharging a patient who will return home
must consider whether all the household members were infected
previously and whether any uninfected household members are at very
high risk for active TB if infected (e.g., children Health-care facilities should either (a) include as part
of their staff an engineer or other professional with expertise in
ventilation or (b) have this expertise available from a consultant who
is an expert in ventilation engineering and who also has hospital
experience. These persons should work closely with infection-control
staff to assist in controlling airborne infections.
Ventilation system designs in health-care facilities
should meet any applicable federal, state, and local requirements.
The direction of airflow in health-care facilities should
be designed, constructed, and maintained so that air flows from clean
areas to less-clean areas.
Health-care facilities serving populations that have a
high prevalence of TB may need to supplement the general ventilation or
use additional engineering approaches (i.e., HEPA filtration or UVGI)
in general-use areas where TB patients are likely to go (e.g., waiting-
room areas, emergency departments, and radiology suites). A single-
pass, nonrecirculating system that exhausts air to the outside, a
recirculation system that passes air through HEPA filters before
recirculating it to the general ventilation system, or upper air UVGI
may be used in such areas.
2. Additional Engineering Control Approaches
a. HEPA filtration.
HEPA filters may be used in a number of ways to reduce or eliminate
infectious droplet nuclei from room air or exhaust (Suppl. 3). These
methods include placement of HEPA filters (a) in exhaust ducts
discharging air from booths or enclosures into the surrounding room;
(b) in ducts or in ceiling- or wall-mounted units, for recirculation of
air within an individual room (fixed recirculation systems); (c) in
portable air cleaners; (d) in exhaust ducts to remove droplet nuclei
from air being discharged to the outside, either directly or through
ventilation equipment; and (e) in ducts discharging air from the TB
isolation room into the general ventilation system. In any application,
HEPA filters should be installed carefully and maintained meticulously
to ensure adequate functioning.
The manufacturers of in-room air cleaning equipment should provide
documentation of the HEPA filter efficiency and the efficiency of the
device in lowering room air contaminant levels.
b. UVGI.
For general-use areas in which the risk for transmission of M.
tuberculosis is relatively high, UVGI lamps may be used as an adjunct
to ventilation for reducing the concentration of infectious droplet
nuclei (Suppl. 3), although the effectiveness of such units has not
been evaluated adequately. Ultraviolet (UV) units can be installed in a
room or corridor to irradiate the air in the upper portion of the room
(i.e., upper-room air irradiation), or they can be installed in ducts
to irradiate air passing through the ducts. UV units installed in ducts
should not be substituted for HEPA filters in ducts that discharge air
from TB isolation rooms into the general ventilation system. However,
UV units can be used in ducts that recirculate air back into the same
room.
To function properly and decrease hazards to HCWs and others in the
health-care facility, UV lamps should be installed properly and
maintained adequately, which includes the monitoring of irradiance
levels. UV tubes should be changed according to the manufacturer's
instructions or when meter readings indicate tube failure. An employee
trained in the use and handling of UV lamps should be responsible for
these measures and for keeping maintenance records. Applicable safety
guidelines should be followed. Caution should be exercised to protect
HCWs, patients, visitors, and others from excessive exposure to UV
radiation.
G. Respiratory Protection
Personal respiratory protection should be used by (a)
persons entering rooms in which patients with known or suspected
infectious TB are being isolated, (b) persons present during cough-
inducing or aerosol-generating procedures performed on such patients,
and (c) persons in other settings where administrative and engineering
controls are not likely to protect them from inhaling infectious
airborne droplet nuclei (Suppl. 4). These other settings include
transporting patients who may have infectious TB in emergency transport
vehicles and providing urgent surgical or dental care to patients who
may have infectious TB before a determination has been made that the
patient is noninfectious (Suppl. 1).
Respiratory protective devices used in health-care
settings for protection against M. tuberculosis should meet the
following standard performance criteria:
1. The ability to filter particles 1 m in size in the
unloaded* state with a filter efficiency of 95% (i.e.,
filter leakage of 5%), given flow rates of up to 50 L per
minute.
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*Some filters become more efficient as they become loaded with
dust. Health-care settings do not have enough dust in the air to
load a filter on a respirator. Therefore, the filter efficiency for
respirators used in health-care settings must be determined in the
unloaded state.
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2. The ability to be qualitatively or quantitatively fit tested in
a reliable way to obtain a face-seal leakage of 10% (54,55).
3. The ability to fit the different facial sizes and
characteristics of HCWs, which can usually be met by making the
respirators available in at least three sizes.
4. The ability to be checked for facepiece fit, in accordance with
standards established by the Occupational Safety and Health
Administration (OSHA) and good industrial hygiene practice, by HCWs
each time they put on their respirators (54,55).
The facility's risk assessment may identify a limited
number of selected settings (e.g., bronchoscopy performed on patients
suspected of having TB or autopsy performed on deceased persons
suspected of having had active TB at the time of death) where the
estimated risk for transmission of M. tuberculosis may be such that a
level of respiratory protection exceeding the standard performance
criteria is appropriate. In such circumstances, a level of respiratory
protection exceeding the standard criteria and compatible with patient-
care delivery (e.g., more protective negative-pressure respirators;
powered air-purifying particulate respirators [PAPRs]; or positive-
pressure air-line, half-mask respirators) should be provided by
employers to HCWs who are exposed to M. tuberculosis. Information on
these and other respirators is in the NIOSH Guide to Industrial
Respiratory Protection (55) and in Supplement 4 of this document.
In some settings, HCWs may be at risk for two types of
exposure: (a) inhalation of M. tuberculosis and (b) mucous membrane
exposure to fluids that may contain bloodborne pathogens. In these
settings, protection against both types of exposure should be used.
When operative procedures (or other procedures requiring a
sterile field) are performed on patients who may have infectious TB,
respiratory protection worn by the HCW should serve two functions: (a)
It should protect the surgical field from the respiratory secretions of
the HCW, and (b) it should protect the HCW from infectious droplet
nuclei that may be expelled by the patient or generated by the
procedure. Respirators with exhalation valves and most positive-
pressure respirators do not protect the sterile field.
Health-care facilities in which respiratory protection is
used to prevent inhalation of M. tuberculosis are required by OSHA to
develop, implement, and maintain a respiratory protection program
(Suppl. 4). All HCWs who use respiratory protection should be included
in this program. Visitors to TB patients should be given respirators to
wear while in isolation rooms, and they should be given general
instructions on how to use their respirators.
Facilities that do not have isolation rooms and do not
perform cough-inducing procedures on patients who may have TB may not
need to have a respiratory protection program for TB. However, such
facilities should have written protocols for the early identification
of patients who have signs or symptoms of TB and procedures for
referring these patients to a facility where they can be evaluated and
managed appropriately. These protocols should be evaluated regularly
and revised as needed.
Surgical masks are designed to prevent the respiratory
secretions of the person wearing the mask from entering the air. To
reduce the expulsion of droplet nuclei into the air, patients suspected
of having TB should wear surgical masks when not in TB isolation rooms.
These patients do not need to wear particulate respirators, which are
designed to filter the air before it is inhaled by the person wearing
the respirator. Patients suspected of having or known to have TB should
never wear a respirator that has an exhalation valve, because this type
of respirator does not prevent expulsion of droplet nuclei into the
air.
H. Cough-Inducing and Aerosol-Generating Procedures
1. General Guidelines
Procedures that involve instrumentation of the lower respiratory
tract or induce coughing can increase the likelihood of droplet nuclei
being expelled into the air. These cough-inducing procedures include
endotracheal intubation and suctioning, diagnostic sputum induction,
aerosol treatments (e.g., pentamidine therapy), and bronchoscopy. Other
procedures that can generate aerosols (e.g., irrigation of tuberculous
abscesses, homogenizing or lyophilizing tissue, or other processing of
tissue that may contain tubercle bacilli) are also covered by these
recommendations.
Cough-inducing procedures should not be performed on
patients who may have infectious TB unless the procedures are
absolutely necessary and can be performed with appropriate precautions.
All cough-inducing procedures performed on patients who
may have infectious TB should be performed using local exhaust
ventilation devices (e.g., booths or special enclosures) or, if this is
not feasible, in a room that meets the ventilation requirements for TB
isolation.
HCWs should wear respiratory protection when present in
rooms or enclosures in which cough-inducing procedures are being
performed on patients who may have infectious TB.
After completion of cough-inducing procedures, patients
who may have infectious TB should remain in their isolation rooms or
enclosures and not return to common waiting areas until coughing
subsides. They should be given tissues and instructed to cover their
mouths and noses with the tissues when coughing. If TB patients must
recover from sedatives or anesthesia after a procedure (e.g, after a
bronchoscopy), they should be placed in separate isolation rooms (and
not in recovery rooms with other patients) while they are being
monitored.
Before the booth, enclosure, or room is used for another
patient, enough time should be allowed to pass for at least 99% of
airborne contaminants to be removed. This time will vary according to
the efficiency of the ventilation or filtration used (Suppl. 3, Table
S3-1).
2. Special Considerations for Bronchoscopy
If performing bronchoscopy in positive-pressure rooms
(e.g., operating rooms) is unavoidable, TB should be ruled out as a
diagnosis before the procedure is performed. If the bronchoscopy is
being performed for the purpose of diagnosing pulmonary disease and
that diagnosis could include TB, the procedure should be performed in a
room that meets TB isolation ventilation requirements.
3. Special Considerations for the Administration of Aerosolized
Pentamidine
Patients should be screened for active TB before
prophylactic therapy with aerosolized pentamidine is initiated.
Screening should include obtaining a medical history and performing
skin testing and chest radiography.
Before each subsequent treatment with aerosolized
pentamidine, patients should be screened for symptoms suggestive of TB
(e.g., development of a productive cough). If such symptoms are
elicited, a diagnostic evaluation for TB should be initiated.
Patients who have suspected or confirmed active TB should
take, if clinically practical, oral prophylaxis for P. carinii
pneumonia.
I. Education and Training of HCWs
All HCWs, including physicians, should receive education regarding
TB that is relevant to persons in their particular occupational group.
Ideally, training should be conducted before initial assignment, and
the need for additional training should be reevaluated periodically
(e.g., once a year). The level and detail of this education will vary
according to the HCW's work responsibilities and the level of risk in
the facility (or area of the facility) in which the HCW works. However,
the program may include the following elements:
The basic concepts of M. tuberculosis transmission,
pathogenesis, and diagnosis, including information concerning the
difference between latent TB infection and active TB disease, the signs
and symptoms of TB, and the possibility of reinfection.
The potential for occupational exposure to persons who
have infectious TB in the health-care facility, including information
concerning the prevalence of TB in the community and facility, the
ability of the facility to properly isolate patients who have active
TB, and situations with increased risk for exposure to M. tuberculosis.
The principles and practices of infection control that
reduce the risk for transmission of M. tuberculosis, including
information concerning the hierarchy of TB infection-control measures
and the written policies and procedures of the facility. Site-specific
control measures should be provided to HCWs working in areas that
require control measures in addition to those of the basic TB
infection-control program.
The purpose of PPD skin testing, the significance of a
positive PPD test result, and the importance of participating in the
skin-test program.
The principles of preventive therapy for latent TB
infection. These principles include the indications, use,
effectiveness, and the potential adverse effects of the drugs (Suppl.
2).
The HCW's responsibility to seek prompt medical evaluation
if a PPD test conversion occurs or if symptoms develop that could be
caused by TB. Medical evaluation will enable HCWs who have TB to
receive appropriate therapy and will help to prevent transmission of M.
tuberculosis to patients and other HCWs.
The principles of drug therapy for active TB.
The importance of notifying the facility if the HCW is
diagnosed with active TB so that contact investigation procedures can
be initiated.
The responsibilities of the facility to maintain the
confidentiality of the HCW while ensuring that the HCW who has TB
receives appropriate therapy and is noninfectious before returning to
duty.
The higher risks associated with TB infection in persons
who have HIV infection or other causes of severely impaired cell-
mediated immunity, including (a) the more frequent and rapid
development of clinical TB after infection with M. tuberculosis, (b)
the differences in the clinical presentation of disease, and (c) the
high mortality rate associated with MDR-TB in such persons.
The potential development of cutaneous anergy as immune
function (as measured by CD4+ T-lymphocyte counts) declines.
Information regarding the efficacy and safety of BCG
vaccination and the principles of PPD screening among BCG recipients.
The facility's policy on voluntary work reassignment
options for immunocompromised HCWs.
J. HCW Counseling, Screening, and Evaluation
A TB counseling, screening, and prevention program for HCWs should
be established to protect both HCWs and patients. HCWs who have
positive PPD test results, PPD test conversions, or symptoms suggestive
of TB should be identified, evaluated to rule out a diagnosis of active
TB, and started on therapy or preventive therapy if indicated (5). In
addition, the results of the HCW PPD screening program will contribute
to evaluation of the effectiveness of current infection-control
practices.
1. Counseling HCWs Regarding TB
Because of the increased risk for rapid progression from
latent TB infection to active TB in HIV-infected or otherwise severely
immunocompromised persons, all HCWs should know if they have a medical
condition or are receiving a medical treatment that may lead to
severely impaired cell-mediated immunity. HCWs who may be at risk for
HIV infection should know their HIV status (i.e., they should be
encouraged to voluntarily seek counseling and testing for HIV antibody
status). Existing guidelines for counseling and testing should be
followed routinely (56). Knowledge of these conditions allows the HCW
to seek the appropriate preventive measures outlined in this document
and to consider voluntary work reassignments. Of particular importance
is that HCWs need to know their HIV status if they are at risk for HIV
infection and they work in settings where patients who have drug-
resistant TB may be encountered.
All HCWs should be informed about the need to follow
existing recommendations for infection control to minimize the risk for
exposure to infectious agents; implementation of these recommendations
will greatly reduce the risk for occupational infections among HCWs
(57). All HCWs should also be informed about the potential risks to
severely immunocompromised persons associated with caring for patients
who have some infectious diseases, including TB. It should be
emphasized that limiting exposure to TB patients is the most protective
measure that severely immunosuppressed HCWs can take to avoid becoming
infected with M. tuberculosis. HCWs who have severely impaired cell-
mediated immunity and who may be exposed to M. tuberculosis may
consider a change in job setting to avoid such exposure. HCWs should be
advised of the option that severely immunocompromised HCWs can choose
to transfer voluntarily to areas and work activities in which there is
the lowest possible risk for exposure to M. tuberculosis. This choice
should be a personal decision for HCWs after they have been informed of
the risks to their health.
Employers should make reasonable accommodations (e.g.,
alternative job assignments) for employees who have a health condition
that compromises cell-mediated immunity and who work in settings where
they may be exposed to M. tuberculosis. HCWs who are known to be
immunocompromised should be referred to employee health professionals
who can individually counsel the employees regarding their risk for TB.
Upon the request of the immunocompromised HCW, employers should offer,
but not compel, a work setting in which the HCW would have the lowest
possible risk for occupational exposure to M. tuberculosis. Evaluation
of these situations should also include consideration of the provisions
of the Americans With Disabilities Act of 1990* and other applicable
federal, state, and local laws.
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*Americans With Disabilities Act of 1990. P.L. 101-336, 42
U.S.C. 12101 et seq.
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All HCWs should be informed that immunosuppressed HCWs
should have appropriate follow-up and screening for infectious
diseases, including TB, provided by their medical practitioner. HCWs
who are known to be HIV-infected or otherwise severely immunosuppressed
should be tested for cutaneous anergy at the time of PPD testing
(Suppl. 2). Consideration should be given to retesting, at least every
6 months, those immunocompromised HCWs who are potentially exposed to
M. tuberculosis because of the high risk for rapid progression to
active TB if they become infected.
Information provided by HCWs regarding their immune status
should be treated confidentially. If the HCW requests voluntary job
reassignment, the confidentiality of the HCW should be maintained.
Facilities should have written procedures on confidential handling of
such information.
2. Screening HCWs for Active TB
Any HCW who has a persistent cough (i.e., a cough lasting
3 weeks), especially in the presence of other signs or
symptoms compatible with active TB (e.g., weight loss, night sweats,
bloody sputum, anorexia, or fever), should be evaluated promptly for
TB. The HCW should not return to the workplace until a diagnosis of TB
has been excluded or until the HCW is on therapy and a determination
has been made that the HCW is noninfectious.
3. Screening HCWs for Latent TB Infection
The risk assessment should identify which HCWs have
potential for exposure to M. tuberculosis and the frequency with which
the exposure may occur. This information is used to determine which
HCWs to include in the skin-testing program and the frequency with
which they should be tested (Table 2).
If HCWs are from risks groups with increased prevalence of
TB, consideration may be given to including them in the skin-testing
program, even if they do not have potential occupational exposure to M.
tuberculosis, so that converters can be identified and preventive
therapy offered.
Administrators of health-care facilities should ensure
that physicians and other personnel not paid by, but working in, the
facility receive skin testing at appropriate intervals for their
occupational group and work location.
During the pre-employment physical or when applying for
hospital privileges, HCWs who have potential for exposure to M.
tuberculosis (Table 2), including those with a history of BCG
vaccination, should have baseline PPD skin testing performed (Suppl.
2). For HCWs who have not had a documented negative PPD test result
during the preceding 12 months, the baseline PPD testing should employ
the two-step method; this will detect boosting phenomena that might be
misinterpreted as a skin-test conversion. Decisions concerning the use
of the two-step procedure for baseline testing in a particular facility
should be based on the frequency of boosting in that facility.
HCWs who have a documented history of a positive PPD test,
adequate treatment for disease, or adequate preventive therapy for
infection, should be exempt from further PPD screening unless they
develop signs or symptoms suggestive of TB.
PPD-negative HCWs should undergo repeat PPD testing at
regular intervals as determined by the risk assessment (Section II.B).
In addition, these HCWs should be tested whenever they have been
exposed to a TB patient and appropriate precautions were not observed
at the time of exposure (Section II.K.3). Performing PPD testing of
HCWs who work in the same area or occupational group on different
scheduled dates (e.g., test them on their birthdays or on their
employment anniversary dates), rather than testing all HCWs in the area
or group on the same day, may lead to earlier detection of M.
tuberculosis transmission.
All PPD tests should be administered, read, and
interpreted in accordance with current guidelines by specified trained
personnel (Suppl. 2). At the time their test results are read, HCWs
should be informed about the interpretation of both positive and
negative PPD test results. This information should indicate that the
interpretation of an induration that is 5-9 mm in diameter depends on
the HCW's immune status and history of exposure to persons who have
infectious TB. Specifically, HCWs who have indurations of 5-9 mm in
diameter should be advised that such results may be considered positive
for HCWs who are contacts of persons with infectious TB or who have HIV
infection or other causes of severe immunosuppression (e.g.,
immunosuppressive therapy for organ transplantation).
When an HCW who is not assigned regularly to a single work
area has a PPD test conversion, appropriate personnel should identify
the areas where the HCW worked during the time when infection was
likely to have occurred. This information can then be considered in
analyzing the risk for transmission in those areas.
In any area of the facility where transmission of M.
tuberculosis is known to have occurred, a problem evaluation should be
conducted (Section II.K), and the frequency of skin testing should be
determined according to the applicable risk category (Section II.B).
PPD test results should be recorded confidentially in the
individual HCW's employee health record and in an aggregate database of
all HCW PPD test results. The database can be analyzed periodically to
estimate the risk for acquiring new infection in specific areas or
occupational groups in the facility.
4. Evaluation and Management of HCWs Who Have Positive PPD Test Results
or Active TB
a. Evaluation
All HCWs with newly recognized positive PPD test results
or PPD test conversions should be evaluated promptly for active TB.
This evaluation should include a clinical examination and a chest
radiograph. If the history, clinical examination, or chest radiograph
is compatible with active TB, additional tests should be performed
(Section II.C.2). If symptoms compatible with TB are present, the HCW
should be excluded from the workplace until either a) a diagnosis of
active TB is ruled out or b) a diagnosis of active TB was established,
the HCW is being treated, and a determination has been made that the
HCW is noninfectious (Suppl. 2). HCWs who do not have active TB should
be evaluated for preventive therapy according to published guidelines
(Suppl. 2).
If an HCW's PPD test result converts to positive, a
history of confirmed or suspected TB exposure should be obtained in an
attempt to determine the potential source. When the source of exposure
is known, the drug-susceptibility pattern of the M. tuberculosis
isolated from the source should be identified so that the correct
curative or preventive therapy can be initiated for the HCW with the
PPD test conversion. The drug-susceptibility pattern should be recorded
in the HCW's medical record, where it will be available if the HCW
subsequently develops active TB and needs therapy specific for the
drug-susceptibility pattern.
All HCWs, including those with histories of positive PPD
test results, should be reminded periodically about the symptoms of TB
and the need for prompt evaluation of any pulmonary symptoms suggestive
of TB.
b. Routine and follow-up chest radiographs.
Routine chest radiographs are not required for
asymptomatic, PPD-negative HCWs. HCWs with positive PPD test results
should have a chest radiograph as part of the initial evaluation of
their PPD test; if negative, repeat chest radiographs are not needed
unless symptoms develop that could be attributed to TB (58). However,
more frequent monitoring for symptoms of TB may be considered for
recent converters and other PPD-positive HCWs who are at increased risk
for developing active TB (e.g., HIV-infected or otherwise severely
immunocompromised HCWs).
c. Workplace restrictions.
(1) Active TB.
HCWs with pulmonary or laryngeal TB pose a risk to
patients and other HCWs while they are infectious, and they should be
excluded from the workplace until they are noninfectious. The same work
restrictions apply to all HCWs regardless of their immune status.
Before the HCW who has TB can return to the workplace, the
health-care facility should have documentation from the HCW's health-
care provider that the HCW is receiving adequate therapy, the cough has
resolved, and the HCW has had three consecutive negative sputum smears
collected on different days. After work duties are resumed and while
the HCW remains on anti-TB therapy, facility staff should receive
periodic documentation from the HCW's health-care provider that the HCW
is being maintained on effective drug therapy for the recommended time
period and that the sputum AFB smears continue to be negative.
HCWs with active laryngeal or pulmonary TB who discontinue
treatment before they are cured should be evaluated promptly for
infectiousness. If the evaluation determines that they are still
infectious, they should be excluded from the workplace until treatment
has been resumed, an adequate response to therapy has been documented,
and three more consecutive sputum AFB smears collected on different
days have been negative.
HCWs who have TB at sites other than the lung or larynx
usually do not need to be excluded from the workplace if a diagnosis of
concurrent pulmonary TB has been ruled out.
(2) Latent TB infection.
HCWs receiving preventive treatment for latent TB
infection should not be restricted from their usual work activities.
HCWs with latent TB infection who cannot take or who do
not accept or complete a full course of preventive therapy should not
be excluded from the workplace. These HCWs should be counseled about
the risk for developing active TB and instructed regularly to seek
prompt evaluation if signs or symptoms develop that could be caused by
TB.
K. Problem Evaluation
Epidemiologic investigations may be indicated for several
situations. These include, but are not limited to, (a) the occurrence
of PPD test conversions or active TB in HCWs; (b) the occurrence of
possible person-to-person transmission of M. tuberculosis; and (c)
situations in which patients or HCWs with active TB are not promptly
identified and isolated, thus exposing other persons in the facility to
M. tuberculosis. The general objectives of the epidemiologic
investigations in these situations are as follows:
(1) To determine the likelihood that transmission of and infection
with M. tuberculosis has occurred in the facility;
(2) To determine the extent to which M. tuberculosis has been
transmitted;
(3) To identify those persons who have been exposed and infected,
enabling them to receive appropriate clinical management;
(4) To identify factors that could have contributed to transmission
and infection and to implement appropriate interventions; and
(5) To evaluate the effectiveness of any interventions that are
implemented and to ensure that exposure to and transmission of M.
tuberculosis have been terminated.
The exact circumstances of these situations are likely to vary
considerably, and the associated epidemiologic investigations should be
tailored to the individual circumstances. The following sections
provide general guidance for conducting these investigations.
1. Investigating PPD Test Conversions and Active TB in HCWs
a. Investigating PPD test conversions in HCWs.
PPD test conversions may be detected in HCWs as a result of a
contact investigation, in which case the probable source of exposure
and transmission is already known (Section II.K.3.), or as a result of
routine screening, in which case the probable source of exposure and
infection is not already known and may not be immediately apparent.
If a skin-test conversion in an HCW is identified as part of
routine screening, the following steps should be considered (Figure 2):
The HCW should be evaluated promptly for active TB. The
initial evaluation should include a thorough history, physical
examination, and chest radiograph. On the basis of the initial
evaluation, other diagnostic procedures (e.g., sputum examination) may
be indicated.
If appropriate, the HCW should be placed on preventive or
curative therapy in accordance with current guidelines (Suppl. 2) (5).
A history of possible exposure to M. tuberculosis should
be obtained from the HCW to determine the most likely source of
infection. When the source of infection is known, the drug-
susceptibility pattern of the M. tuberculosis isolate from the source
patient should be identified to determine appropriate preventive or
curative therapy regimens.
If the history suggests that the HCW was exposed to and
infected with M. tuberculosis outside the facility, no further
epidemiologic investigation to identify a source in the facility is
necessary.
If the history does not suggest that the HCW was exposed
and infected outside the facility but does identify a probable source
of exposure in the facility, contacts of the suspected source patient
should be identified and evaluated. Possible reasons for the exposure
and transmission should be evaluated (Table 4), interventions should be
implemented to correct these causes, and PPD testing of PPD-negative
HCWs should be performed immediately and repeated after 3 months.
If no additional PPD test conversions are detected on follow-up
testing, the investigation can be terminated.
If additional PPD test conversions are detected on follow-up
testing, the possible reasons for exposure and transmission should be
reassessed, the appropriateness of and degree of adherence to the
interventions implemented should be evaluated, and PPD testing of PPD-
negative HCWs should be repeated after another 3 months.
If no additional PPD test conversions are detected on the second
round of follow-up testing, the investigation can be terminated.
However, if additional PPD conversions are detected on the second round
of follow-up testing, a high-risk protocol should be implemented in the
affected area or occupational group, and the public health department
or other persons with expertise in TB infection control should be
consulted.
If the history does not suggest that the HCW was exposed
to and infected with M. tuberculosis outside the facility and does not
identify a probable source of exposure in the facility, further
investigation to identify the probable source patient in the facility
is warranted.
The interval during which the HCW could have been infected should
be estimated. Generally, this would be the interval from 10 weeks
before the most recent negative PPD test through 2 weeks before the
first positive PPD test (i.e., the conversion).
Laboratory and infection-control records should be reviewed to
identify all patients or HCWs who have suspected or confirmed
infectious TB and who could have transmitted M. tuberculosis to the
HCW.
If this process does identify a likely source patient, contacts of
the suspected source patient should be identified and evaluated, and
possible reasons for the exposure and transmission should be evaluated
(Table 4). Interventions should be implemented to correct these causes,
and PPD testing of PPD-negative HCWs should be repeated after 3 months.
However, if this process does not identify a probable source case, PPD
screening results of other HCWs in the same area or occupational group
should be reviewed for additional evidence of M. tuberculosis
transmission. If sufficient additional PPD screening results are not
available, appropriate personnel should consider conducting additional
PPD screening of other HCWs in the same area or occupational group.
BILLING CODE 4163-18-P
TN28OC94.002
TN28OC94.003
BILLING CODE 4163-18-C
Table 4.--Examples of Potential Problems That Can Occur When Identifying or Isolating Patients Who May Have
Infectious Tuberculosis (TB)
----------------------------------------------------------------------------------------------------------------
Situation Potential problem Intervention
----------------------------------------------------------------------------------------------------------------
Patient identification Patient with signs or symptoms not Review triage procedures, facilities, and
during triage identified. practices.
Patient had no symptoms listed in Revaluate triage protocol.
triage protocol.
During review of Positive smear: results available >24 Change laboratory practices. Assess potential
laboratory results hours* after submitted. barriers. Explore alternatives.
Positive smear: results available but Educate appropriate personnel. Review protocol
action not taken promptly. for management of positive smear results.
Positive culture: results not Change laboratory practices. Assess potential
available for >3 weeks*. barriers. Explore alternatives.
Postive culture: results available but Educate appropriate personnel. Review protocol
action not taken promptly. for management of positive culture results.
Positive culture: susceptibility Change laboratory practices. Assess potential
results not available for >6 weeks*. barriers. Explore alternatives.
Positive culture: susceptibility Educate appropriate personnel. Review protocol
results available but action not for management of positive culture
taken promptly. susceptibility results.
At time of diagnosis Patient with signs/symptoms of TB: Educate appropriate personnel. Evaluate
and during isolation appropriate tests not ordered protocols for TB detection.
promptly.
Isolation room unavailable............ Reassess need for number of isolation rooms.
Isolation not ordered or discontinued Educate patients and appropriate personnel.
too soon, or isolation policy not Evaluate institutional barriers to
followed properly (e.g., patients implementation of isolation policy.
going outside of room).
Personnel not properly using Educate appropriate personnel. Evaluate
respiratory protection. regularly scheduled re-education. Evaluate
institutional barriers to use of respiratory
protection.
Isolation room or procedure room not Make appropriate engineering modifications.
at negative pressure reslative to Establish protocols for regularly monitoring
surrounding areas. and maintaining negative pressure.
Inadequate air circulation............ Make appropriate engineering modifications.
Door left open........................ Educate appropriate personnel and patients.
Evaluate self-closing doors, comfort levels in
the room, and other measures to promote door
closing.
----------------------------------------------------------------------------------------------------------------
*These time intervals are used as examples and should not be considered absolute standards.
If this review and/or screening does not identify additional PPD
conversions, nosocomial transmission is less likely, and the contact
investigation can probably be terminated. Whether the HCW's PPD test
conversion resulted from occupational exposure and infection is
uncertain; however, the absence of other data implicating nosocomial
transmission suggests that the conversion could have resulted from (a)
unrecognized exposure to M. tuberculosis outside the facility; (b)
cross-reactivity with another antigen (e.g., nontuberculous
mycobacteria); (c) errors in applying, reading, or interpreting the
test; (d) false positivity caused by the normal variability of the
test; or (e) false positivity caused by a defective PPD preparation.
If this review and/or screening does identify additional PPD test
conversions, nosocomial transmission is more likely. In this situation,
the patient identification (i.e., triage) process, TB infection-control
policies and practices, and engineering controls should be evaluated to
identify problems that could have led to exposure and transmission
(Table 4).
If no such problems are identified, a high-risk protocol should be
implemented in the affected area or occupational group, and the public
health department or other persons with expertise in TB infection
control should be consulted.
If such problems are identified, appropriate interventions should
be implemented to correct the problem(s), and PPD skin testing of PPD-
negative HCWs should be repeated after 3 months.
If no additional PPD conversions are detected on follow-up testing,
the investigation can be terminated.
If additional PPD conversions are detected on follow-up testing,
the possible reasons for exposure and transmission should be
reassessed, the appropriateness of and adherence to the interventions
implemented should be evaluated, and PPD skin testing of PPD-negative
HCWs should be repeated after another 3 months.
If no additional PPD test conversions are detected on this second
round of follow-up testing, the investigation can be terminated.
However, if additional PPD test conversions are detected on the second
round of follow-up testing, a high-risk protocol should be implemented
in the affected area or occupational group, and the public health
department or other persons with expertise in TB infection control
should be consulted.
b. Investigating cases of active TB in HCWs.
If an HCW develops active TB, the following steps should be taken:
The case should be evaluated epidemiologically, in a
manner similar to PPD test conversions in HCWs, to determine the
likelihood that it resulted from occupational transmission and to
identify possible causes and implement appropriate interventions if the
evaluation suggests such transmission.
Contacts of the HCW (e.g., other HCWs, patients, visitors,
and others who have had intense exposure to the HCW) should be
identified and evaluated for TB infection and disease (Section II.K.3;
Suppl. 2). The public health department should be notified immediately
for consultation and to allow for investigation of community contacts
who were not exposed in the health-care facility.
The public health department should notify facilities when
HCWs with TB are reported by physicians so that an investigation of
contacts can be conducted in the facility. The information provided by
the health department to facilities should be in accordance with state
or local laws to protect the confidentiality of the HCW.
2. Investigating Possible Patient-to-Patient Transmission of M.
tuberculosis
Surveillance of active TB cases in patients should be conducted. If
this surveillance suggests the possibility of patient-to-patient
transmission of M. tuberculosis (e.g., a high proportion of TB patients
had prior admissions during the year preceding onset of their TB, the
number of patients with drug-resistant TB increased suddenly, or
isolates obtained from multiple patients had identical and
characteristic drug-susceptibility or DNA fingerprint patterns), the
following steps should be taken:
Review the HCW PPD test results and patient surveillance
data for the suspected areas to detect additional patients or HCWs with
PPD test conversions or active disease.
Look for possible exposures that patients with newly
diagnosed TB could have had to other TB patients during previous
admissions. For example, were the patients admitted to the same room or
area, or did they receive the same procedure or go to the same
treatment area on the same day?
If the evaluation thus far suggests transmission has occurred, the
following steps should be taken:
Evaluate possible causes of the transmission (e.g.,
problem with patient detection, institutional barriers to implementing
appropriate isolation practices, or inadequate engineering controls)
(Table 4).
Ascertain whether other patients or HCWs could have been
exposed; if so, evaluate these persons for TB infection and disease
(Section II.K.3; Suppl. 2).
Notify the public health department so they can begin a
community contact investigation if necessary.
3. Investigating Contacts of Patients and HCWs Who Have Infectious TB
If a patient who has active TB is examined in a health-care
facility and the illness is not diagnosed correctly, resulting in
failure to apply appropriate precautions, or if an HCW develops active
TB and exposes other persons in the facility, the following steps
should be taken when the illness is later diagnosed correctly:
To identify other patients and HCWs who were exposed to
the source patient before isolation procedures were begun, interview
the source patient and all applicable personnel and review that
patient's medical record. Determine the areas of the facility in which
the source patient was hospitalized, visited, or worked before being
placed in isolation (e.g., outpatient clinics, hospital rooms,
treatment rooms, radiology and procedure areas, and patient lounges)
and the HCWs who may have been exposed during that time (e.g., persons
providing direct care, therapists, clerks, transportation personnel,
housekeepers, and social workers).
The contact investigation should first determine if M.
tuberculosis transmission has occurred from the source patient to those
persons with whom the source patient had the most intense contact.
Administer PPD tests to the most intensely exposed HCWs
and patients as soon as possible after the exposure has occurred. If
transmission did occur to the most intensely exposed persons, then
those persons with whom the patient had less contact should be
evaluated. If the initial PPD test result is negative, a second test
should be administered 12 weeks after the exposure was terminated.
Those persons who were exposed to M. tuberculosis and who
have either a PPD test conversion or symptoms suggestive of TB should
receive prompt clinical evaluation and, if indicated, chest radiographs
and bacteriologic studies should be performed (Suppl. 2). Those persons
who have evidence of newly acquired infection or active disease should
be evaluated for preventive or curative therapy (Suppl. 2). Persons who
have previously had positive PPD test results and who have been exposed
to an infectious TB patient do not require a repeat PPD test or a chest
radiograph unless they have symptoms suggestive of TB.
In addition to PPD testing those HCWs and patients who
have been exposed to M. tuberculosis because a patient was not isolated
promptly or an HCW with active TB was not identified promptly, the
investigation should determine why the diagnosis of TB was delayed. If
the correct diagnosis was made but the patient was not isolated
promptly, the reasons for the delay need to be defined so that
corrective actions can be taken.
L. Coordination With the Public Health Department
As soon as a patient or HCW is known or suspected to have
active TB, the patient or HCW should be reported to the public health
department so that appropriate follow-up can be arranged and a
community contact investigation can be performed. The health department
should be notified well before patient discharge to facilitate follow-
up and continuation of therapy. A discharge plan coordinated with the
patient or HCW, the health department, and the inpatient facility
should be implemented.
The public health department should protect the
co
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