Tuberculosis in Hospital Personnel

Abstract

Tuberculosis (TB) skin testing practices and the prevalence and inherent risk of TB infection among hospital employees in 167 North Carolina (NC) hospitals were determined from a 79% (132/167) response to a tuberculosis screening questionnaire. Preemployment TB skin testing was performed by 98% of responding hospitals, primarily (87%) by the Mantoux method. TB skin test reactions of ≥ 10 mm were interpreted as significant by 72% and at the appropriate time interval of 48 to 72 hours after administration by 80%. The booster test was routinely performed in 12% of the hospitals. TB infection prevalence among new employees during 1983 was 6.3% (260/4137) in 30 hospitals supplying these data. A positive correlation was noted between employee infection prevalence and county TB case rates (P = .014). Skin test conversion data from 56 hospitals across the state revealed a five year mean conversion rate of 1.14% among 71,253 personnel. There was an association between the incidence of TB in the general population and the frequency of conversions among hospital employees in corresponding geographical regions. Similarly, the incidence of TB among approximately 100,000 NC hospital employees in 1983 and 1984 was less than the incidence in the general population. These associations suggest that the incidence of TB infection among hospital personnel may reflect the prevalence of tuberculosis in the community rather than an occupational hazard. Annual TB skin testing of hospital employees may be justified in eastern North Carolina where the incidence of tuberculosis (22-30 cases/ 100,000) is greater than the national average and where the risk of new TB infection among hospital employees is relatively common (≥1.5%).

Tuberculosis among Health Care Workers

“…34 This higher conversion rate was attributed to immunologic boosting, because conversions on tuberculin testing were associated with older age but not with exposure. 34 In four studies in which the ratio of the number of workers to the annual number of admissions for tuberculosis was between 18 and 92, the annual risk of infection ranged from 1.7 to 3.9 percent 28,32,36,43 and was correlated with actual exposure in two of the institutions. 32,43 In hospitals where there were more than 200 admissions annually for tuberculosis or where the ratio of workers to annual admissions was less than 10, infection occurred in 1 to 10 percent of workers each year.…”

“…17 Studies using data from disease registries (summarized in Table 1) have reported an estimated risk ratio of 0.6 to 2.0, indicating at most only a modest increase in risk. 20,21,23,[26][27][28] Both cohort and disease-registry studies may be limited by the inability to distinguish occupational from nonoccupational exposure. These studies may underestimate the risk because of the failure to standardize for age 20,[26][27][28] or because the working population is younger and has a lower incidence of tuberculosis than the general population (the "healthy-worker effect").…”

“…20,21,23,[26][27][28] Both cohort and disease-registry studies may be limited by the inability to distinguish occupational from nonoccupational exposure. These studies may underestimate the risk because of the failure to standardize for age 20,[26][27][28] or because the working population is younger and has a lower incidence of tuberculosis than the general population (the "healthy-worker effect"). 22,30 Disease-registry studies may misclassify exposure because the information on occupation is incomplete or workers have changed jobs between the time of exposure and the development of the disease.…”

“…37,41,42 In one study the prevalence of infection was directly proportional to the duration of employment in the hospital. 37 Participation rates were reported to be high in only two of the studies reviewed 38,39 and were not specified, 31,32,34,36,40,[42][43][44] variable, 28,35 or low 37 in the remainder, which may have resulted in a substantial selection bias. Rates of infection among all hospital workers 28,31,34-36,38,39,42-44 are probably lower than rates only among workers at high risk.…”

Dying for work: The magnitude of US mortality from selected causes of death associated with occupation

“…Workers with potential occupational exposure in the mid-1990s were considered to be those in hospitals, nursing homes, homeless shelters, and correctional facilities (estimated total 5.3 million). For hospitals OSHA estimated lifetime risk of TB infection due to occupational exposure for workers in hospitals with good exposure controls [Aitken et al, 1987], some controls [Price and Rutala, 1987], and poor controls [Boudreau et al, 1997]. In each case a range of excess risks was given which corresponded to the range of background rates in different parts of the country, since excess risk depends on the level of background risk.…”