CDC History of Tuberculosis Control - Medical and Public Health ...

disease to health care workers caring for the
patients involved in these outbreaks.
With recognition of the increased risk for TB
among persons with HIV infection, in 1990
CDC issued Guidelines for Preventing the
Transmission of Tuberculosis in Health-Care
Settings with Special Focus on HIV-Related
Issues. Despite these guidelines,
implementation of appropriate infection
control measures was incomplete in many
hospitals, and some of the published reports of
nosocomial transmission documented lapses in
or absence of infection control measures in the
health care facilities. Because of its legal
mandate to ensure that no worker is harmed
as a result of his or her work experience, as
well as the outbreaks of MDR TB, in 1992 the
National Institute for Occupational Safety and
Health (NIOSH) recommended the use of
powered-air purifying respirators (PAPRs) by
health care workers potentially exposed to
M. tuberculosis.
As a result of the ongoing outbreaks of TB and
the NIOSH recommendation for the use of
PAPRs, the adequacy of the 1990 guidelines
was discussed at a large national meeting
convened in 1993. In attendance at this
meeting were representatives from multiple
groups concerned with nosocomial
transmission of M. tuberculosis, including
infection control practitioners, labor
representatives, and occupational medicine
practitioners. The meeting concluded that in
most of the outbreak settings, the 1990
guidelines had not been adequately
implemented, and there was a need for revised
and expanded guidelines. In 1993 a draft of the
revised guidelines was published in the Federal
Register for public comment. After a period of
comment and public meetings, the report
Guidelines for Preventing the Transmission of
Mycobacterium tuberculosis in Health-Care
Facilities, 1994 was published in the Morbidity
and Mortality Weekly Report. This document
contained detailed, comprehensive
recommendations for prevention of
Notable Events in TB Control
61
Hierarchy of TB Control Measures
I. Source Control
(most effective, efficient)
II. Environmental
Control
III. Protective devices
for workers (least
effective, efficient)
nosocomial transmission of M. tuberculosis.
Included in the recommendations was a
hierarchy of controls composed of, most
importantly, administrative controls
(including assignment of responsibility, risk
assessment, development of a TB infection
control plan with periodic reassessment, and
tuberculin skin testing of health care workers),
followed by engineering controls, and then by
personal respiratory protection. Personal
respiratory protection devices that were
recommended for use in the health care setting
needed to meet the following criteria:
1) ability to filter particles of 1 micron with a
filter efficiency of 95%, 2) ability to be fit
tested to obtain a face seal leak of 10% or less,
3) ability to fit different face sizes, and
4) ability to be checked for face-piece fit by
health care workers each time the respirator
was used. At the time the 1994 guidelines were
written, the only respiratory protection device
that was NIOSH-approved and met the above
criteria was the high efficiency particulate air
(HEPA) filter respirators. In July 1995
NIOSH updated its respirator testing and
certification requirements to permit the
approval of other respirators. Under the
updated testing, respirators that contain a
NIOSH-certified N-series filter with 95%
efficiency (N-95) rating meet the
recommendations of the CDC guidelines.
Like NIOSH, the Occupational Safety and
Health Administration (OSHA) has a legal
mandate for the protection of workers;
however, unlike NIOSH, which can only