Objective: To determine the incidence of active tuberculosis (TB) in a cohort of health care workers (HCWs).
Methods: Descriptive study of active TB cases identified in an occupational health screening of 6,112 HCWs between 2005 and 2010. Cases of active TB were defined as those in which Mycobacterium tuberculosis was identified by direct microscopy or culture; those in which there were symptoms or clinical signs of TB and necrotizing granuloma, as detected by histology; and those in which the radiological findings were consistent with active TB.
Results: Among the 6,112 HCWs evaluated, we identified 62 cases of active TB: pulmonary TB (n = 43); pleural TB (n = 15); lymph node TB (n = 2); pericardial TB (n = 1); and cutaneous TB (n = 1). Seven HCWs were asymptomatic at the time of diagnosis. Of the 62 cases of active TB, 48 developed within the first 10 years of occupational exposure in the workplace, 36 of those occurring within the first 5 years. Physicians and nurses accounted for the highest numbers of cases (22 and 21, respectively).
Conclusions: In HCWs employed in Portugal, the TB burden is high. Physicians and nurses are the HCWs who are at the highest risk of developing active TB. We found the risk of developing this disease to be highest in the first years of exposure, as has been reported in previous studies. In high-incidence countries, TB screening of HCWs is important for controlling the transmission of this disease.