Page 55 - L:\GROUP\SDT\zip_disk\Book2.PDF

G. Background. Since 1985, the incidence of tuberculosis (TB) in the general U.S. population has
increased approximately 14 percent, reversing a 30-year downward trend. In 1993, 25,313 new cases
of TB were reported in the United States. 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).
Other factors (e.g., socioeconomic) have also contributed to these increases. Outbreaks have
occurred in hospitals, correctional institutions, homeless shelters, nursing homes, and residential care
facilities for AIDS patients. During 1994 and 1995 there has been a decrease in the number of TB
cases in the United States that is likely been due to increased awareness and efforts in the prevention
and control of TB, including the implementation of TB control measures recommended by the CDC
and required by OSHA.

Recently, drug resistant strains of M. tuberculosis have become a serious concern and cases of
multi-drug-resistant (MDR) TB have occurred in forty states. In a recent New York City study,
33% of cases had organisms resistant to the two most effective drugs available for treating the
disease. When organisms are resistant to both drugs, the course of the treatment increases from
six months to 18-24 months, and the cure rate decreases from 100% to 60% or less.

In a 1992 American Hospital Association survey/CDC survey, 90 of 729 (13%) respondents
reported nosocomial TB transmission to health care workers. More than 80% of those facilities
experienced TB skin test conversions among workers. More than 100 cases of active TB disease
in health care workers were known to CDC and reported to Congress by Dr. William Roper in
the Spring of 1993. Twelve (12) health care workers have died. Nationwide, at least several
hundred employees have become infected and required medical treatment after workplace
exposure to TB. In general, persons who become infected with TB have approximately a 10% risk
for developing active TB in their lifetimes. M. tuberculosis is carried through the air in tiny infectious
droplet nuclei of 1 to 5 microns in diameter. These droplets may be generated when a person with
pulmonary and laryngeal TB disease coughs, speaks, sings, sneezes, or spits. When inhaled by
susceptible persons, the mycobacteria in these droplets may become established in the lungs and, in
some cases, spread throughout the body. After an interval of months, years, or even decades, the
initial infection may then progress to clinical illness (i.e., tuberculosis disease). Transmission of TB is
most likely to occur from persons with pulmonary or laryngeal TB that are not on effective anti-TB
therapy and who have not been placed in respiratory isolation.

In occupational health care settings, where patients with TB are seen, workers exposed to
tuberculosis droplet nuclei are at increased risk of infection with exposure to TB. Certain
high-risk medical procedures that are cough-inducing or aerosol generating can further increase
the risk of infection in health care workers.

The employer’s obligations are those set forth in the Occupational Safety and Health Act (OSH
Act) of 1970. Recommendations for preventing the transmission of TB for health care settings
were originally established with the 1990 CDC Guidelines. In October, of 1994, those guidelines
were revised and published (Appendix A). The new guidelines emphasize the control of TB
through an effective TB infection control program. Under these guidelines the control of TB is to
be accomplished through the early identification, isolation, and treatment of persons with TB, use
of engineering and administrative procedures to reduce the risk of exposure, and through the use
of respiratory protection. OSHA believes these guidelines reflect an industry recognition of the
hazard as well as appropriate, widely recognized, and accepted standards of practice to be
followed by employers in carrying out their responsibilities under the OSH Act.

47