In a national questionnaire survey of 1,494 hospitals Sinkowitz and coworkers found conversion rates based on reports from these hospitals of 0.6 to 0.7 percent/year for 1989 through 1992 (81). Bronchoscopy was associated with a high conversion rate of 3.7 percent/year among personnel. Respiratory therapists were also at high risk, with a rate of 1.0 percent/year. The main body of this report focused on compliance with CDC infection control guidelines, and demographic data on the employees were not included.

In 1995, McCray, Curtis, Onorato, and colleagues initiated a prospective study of health care workers in 32 facilities caring for patients with tuberculosis in six states, New York City, San Francisco, and San Diego (E.McCray and A.B.Curtis, personal communications of data presented at a December 1999 workshop). The sites included nine hospitals, seven health departments, five correctional institutions, two long-term-care facilities, and nine others. All were sites at which care for tuberculosis patients occurred, many in areas with relatively high tuberculosis case rates. During the next 3 years, a skin test conversion rate of 0.8 percent (112/ 13,597) was observed (calculated ARI = 0.28 percent/year). The rate was highest in New York City at 2.4 percent (calculated ARI = 0.81 percent/ year), but no conversions were observed among health care workers in Oregon, Colorado, and Florida. Conversions occurred with about equal frequency in correctional facilities (1.0 percent), health departments (0.9 percent), hospitals (0.8 percent), and long-term-care facilities (1.1 percent). Outreach workers had a risk approximately 2.5 times that of those in other occupations. Foreign birth and Asian or black race were independent predictors of risk, and after adjusting for these variables, no specific occupational risk remained. Some of the annual risks of infection that can be calculated from this study are shown in Table C-12.

TABLE C-12. Calculated Annual Risks of Infection Derived from Tuberculin Skin Test Conversion Data for Selected Groups of Health Care Workers (E.McCray and A.B.Curtis, personal communication)

Health Care Worker Group, Work Sites and Categories, Racial and Demographic Categories

Calculated Annual Risk of Tuberculous Infection (%/year)





Outreach worker


Doctor/physician’s assistant


Not Hispanic, white


Not Hispanic, Black










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