Low risk for tuberculosis in a regional pediatric hospital: nine-year study of community rates and the mandatory employee tuberculin skin-test program.
OBJECTIVE: To assess the risk of Mycobacterium tuberculosis infection and disease among patients and workers in a regional pediatric hospital. DESIGN: Descriptive epidemiological study of the mandatory tuberculin skin testing program of hospital employees at hire and during annual reevaluation, pediatric patients with tuberculosis (TB), efficacy of hospital infection control measures, and community rates of TB. SETTING: 361-bed, university, pediatric hospital serving Cincinnati (1.7 million population). RESULTS: During 1986 through 1994, 2,275 to 4,356 employees were compliant with Mantoux skin testing and screening each year. This represented >97% of the population who were eligible for screening. The cumulative rate of M tuberculosis infection from a previous positive tuberculin skin test was 10% to 12% per year during 1986 through 1994. Among new Mantoux skin-test converters in employees at annual reevaluation, the risk of TB infection was 0.3% in 1993 and 1994. There were no active cases of TB identified during new employee screening or annual reevaluation. Of 62 new Mantoux skin-test converters in 9 years, 23% were foreign-born, 13% were Asian, 23% were African American, 11% received the bacillus of Calmette-Guérin vaccine, and 60% had direct patient care or indirect patient contact. A cluster of five converters occurred in a department with no patient care or contact. Mantoux conversion rates were 1.9 per 1,000 employee patient-care or contact-years and 2.2 per 1,000 employee non-patient-contact years. Twenty pediatric patients with active TB were identified during 1991 to 1994, with < or =6 cases per year, placing this hospital in the low-risk category for M tuberculosis disease. Three children with pulmonary TB were admitted without immediate respiratory isolation, possibly exposing 9 patients and 42 employees; none converted their Mantoux skin tests on retesting. Rates of active TB in Cincinnati were stable during the period (eg, 8/100,000 population in 1994). CONCLUSIONS: Despite intense active surveillance among thousands of hospital employees with >97% annual compliance, tuberculin conversion rates were low, and no cases of active TB were identified during 9 years of follow-up. There was no evidence of transmission of M tuberculosis from infected patients to employees during uncontrolled exposures. Rates of TB in the community were low. These data suggest that rigorous application of the Centers for Disease Control and Prevention guidelines and Occupation Safety and Health Administration regulations for preventing nosocomial TB in pediatric hospitals may be excessive and costly. Special provisions should be made for pediatric hospitals with a proven low risk of transmission of M tuberculosis.