Sepkowitz cites a 1953 study (Mikol et al., 1953) that found that hospital workers with direct patient contact had an 8- to 10-fold higher incidence of tuberculosis compared with that for workers without direct contact. A review by Menzies and colleagues of studies conducted in the 1960s reported that health care workers exposed to patients with known tuberculosis had a four to six times greater incidence of infection with M. tuberculosis than unexposed workers (Menzies et al., 1995). The quality of the studies that they reviewed varied considerably.
In sum, a number of studies indicate that health care workers, especially those who cared for patients, have historically been at higher risk of infection and disease than the general population. By the 1960s, effective treatment of tuberculosis was becoming widely available and public health programs were mobilizing to control if not eliminate the disease. In addition, health care facilities were beginning to adopt some tuberculosis control measures such as screening patients with chest radiographs and isolating those with known or suspected infectious disease.
Active Tuberculosis and Mortality from Tuberculosis CDC reports annually on cases of active tuberculosis nationwide and by state and selected cities (see, e.g., CDC [2000b]). It reports national mortality data but does not break deaths down by state or other category.
Chapter 1 described the resurgence in tuberculosis cases and case rates beginning in 1985, an increase that followed uninterrupted declines since national data were first reported in 1953. After reaching a high of 10.5 per 100,000 population in 1992 (13 percent higher than in 1985), rates began to decline again in 1993. Case rates and case numbers reached their lowest levels yet in 1999, when CDC reported a case rate of 6.4 per 100,000 population and 17,528 cases of tuberculosis (CDC, 2000b). Rates of death from tuberculosis, which also rose in the 1980s and early 1990s, have also declined in recent years from 0.8 per 100,000 in 1989 to 0.4 per 100,000 in 1998, and numbers of deaths declined from 1,970 to 1,110.
CDC data make it clear that tuberculosis is not evenly distributed within the United States. For example, the increase in case rates from 1985 to 1992 was largely concentrated in a few states. During this period, the seven states with case rate increases of 4 percent or more (1984 to 1991) showed a collective increase from 11.2 to 16.8 cases per 100,000 popula-