CDC rules reduce TB cases in hospital workers

Skin-testing rates increase for all hospital staff

While development of a standard for protecting health care workers from tuberculosis infection continues, an investigation of U.S. hospitals reveals that most already have made progress in implementing the Centers for Disease Control and Prevention guidelines for preventing TB transmission.1

Critics of an Occupational Safety and Health Administration (OSHA) standard have maintained that a regulation is unnecessary, and claim that the CDC’s guidelines have been effective in protecting HCWs from occupational TB infection. The study shows that strict adherence to CDC guidelines has indeed decreased occupational TB transmission.

Researchers from the CDC and the American Hospital Association (AHA) surveyed 763 hospitals in 1992, and in 1996 resurveyed 103 random samples of all 1992 respondent hospitals with six or more TB admissions in 1991.

Survey results show that hospitals have made good progress in implementing TB infection control measures to reduce the risk of occupational acquisition of TB infection among health care workers, says study author Gina Pugliese, RN, MS, infection control consultant for the AHA in Chicago.

Because hospitals already have taken many steps to prevent occupational TB transmission, it is unlikely their programs will need to undergo any major changes when a final OSHA standard is issued, she explains. (See cover story in this issue.)

In 1992, 71% (536 of 755 hospitals) reported having isolation rooms that met CDC criteria for acid-fast bacilli isolation: negative air pressure, at least six air exchanges per hour, and air vented directly to the outside. In 1996, the number had increased to 96% (99 of 103 hospitals).

HCWs in 8% of hospitals used a particulate respirator when entering a room of a suspected or confirmed infectious TB patient in 1992 (although the main respiratory protection device used was a surgical, nonfitted mask), while workers in 83% of hospitals were using an N95 respirator in the same circumstances in 1996. Also in 1996, HCWs in 91% of hospitals surveyed participated in a respirator fit-testing program.

In 1992, nurses were included in all tuberculin skin-testing (TST) programs, but along with administrative staff (87%), were included in much greater numbers than house staff (60%), attending physicians (45%), and students (56%). At 89% of hospitals, nurses received TST at least annually, compared with 50% of house staff and 33% of attending physicians.

Results in 1996 showed that all hospitals had some form of TST for nurses and respiratory therapists, and 89% included administrative staff. Hospitals including house staff and attending physicians increased to 89% and 69%, respectively.

The authors note that "only 30 (29%) of 103 hospitals provided data for personnel TST conversion rates during 1992-1996. However, at these facilities, the HCW TST conversion rate decreased from 35 in 1992 to 30 in 1995 and 20 TST conversions per 10,000 HCWs from January to June 1996."

The study also documents decreased patient-to-HCW TB transmission in responding hospitals, from 13% in 1992 to 7% in 1996.

The researchers conclude that continued implementation of CDC guidelines and improved management of HCW skin-test data will further reduce occupational TB transmission.


1. Manangan LP, Simonds DN, Pugliese G. Are U.S. hospitals making progress in implementing guidelines for prevention of Mycobacterium tuberculosis transmission? Arch Intern Med 1998; 158:1,440-1,444.