Introduction: There have been few Latin American studies investigating the fact that the rate of tuberculosis (TB) infection among medical students is higher than the 1.3% rate seen in the population at large. Objective: To describe the cumulative incidence and the relative risk for TB infection among medical students. Method: In 1998, a prospective cohort study was conducted involving medical students at the Universidade Federal do Rio de Janeiro Faculdade de Medicina who tested negative (induration <10 mm) on the tuberculin skin test (TST). Students were tested using the two-step TST method and were retested one year later. The students tested were at two different stages in their training: pre-clinical (no contact with patients) and final year (contact with patients). Information about demographic characteristics, BCG vaccination history, and instances of potential exposure to Mycobacterium tuberculosis were obtained using a standardized questionnaire. Of the 575 students initially enrolled, 72% (414) completed the study. Results: The TSTs of 16 (3.9%) of the 414 students converted, representing a cumulative incidence of 3.9% (95% confidence interval = 1.06 to 12.1). Senior medical students were at an almost fourfold higher risk for M. tuberculosis infection than were those in pre-clinical training. Conclusion: The risk for TST conversion is very high in this population.

Keywords: PPD. Tuberculosis-infection. Tuberculin conversion. Medical students

The objective of this review was to contribute to the debate on the nosocomial transmission of TB among health professionals in a country where TB is endemic. Prior to 1900, there was no reason to believe that health professionals interacting with TB patients were more susceptible to becoming infected with the bacillus than was the general population. Between 1920 and 1930, various studies showed significant findings regarding the rates of positive tuberculin skin tests among students in the area of health care. However, most clinicians remained skeptical about the susceptibility of health professionals to becoming infected with TB. In the various locales where the treatment of patients with TB has been implemented, health professionals have been described as an especially predisposed population to becoming infected with and developing active TB. It is urgent that the scientific community and health professionals become mobilized, recognizing themselves as a population at risk of developing TB, and that actions be taken in order to minimize the potential risks of acquiring the disease at locales where patients with TB are treated.

Keywords: Tuberculosis; Cross infection; Health personnel.

Background: The Hospital Ferreira Machado, utilized, in part, as a clinical training center for graduate students from the Faculdade de Medicina de Campos, admitted 65 tuberculosis (TB) patients in 2001. Objective: To estimate the prevalence of positive tuberculin skin tests (TST) among medical students during distinct periods of their training and to identify and analyze correlated factors. To compare positivity rates, taking into account the booster effect, and estimate incidence of positive TST by class year. Methods: A cross-sectional study was conducted among 500 students registered in the first semester of 2002. Using a structured and validated questionnaire, data regarding demographics, BCG vaccination and potential exposure to TB patients were obtained. A professional licensed by the Health Department administered the TSTs, and the twostep Mantoux method (PPD Rt23) was used. Results: Of the 500 eligible subjects, 316 (63.2%) were excluded. Analysis showed increasing two-step TST positivity rates corresponding to extent of clinical experience (4%, 6.4% and 13.1%) and a tendency toward correlation with professional level. The highest percentage of positive TSTs was found during the period of clinical training, which corresponded to the time of greatest exposure to patients (1000 hours). Conclusions: a) the TST positivity rate was high (7.9%) among students; b) TST was correlated with in-hospital training stage; c) evaluation of the booster effect lead us to highly recommended boosters in order to reduce the number of false-negative TST results.

Keywords: Tuberculin. Tuberculin test. Tuberculosis. Students/Medical. Cross-sectional studies.