Tuberculin Skin Test Conversion among Students during their Educational Course in Medical and Pharmacy Schools: A Multiple Cohort Study


1 Iranian Research Center for HIV/AIDS, Department of Infectious Diseases, Imam Khomeini Hospital, Tehran University of Medical Sciences

2 Medical and Health Promotion Research Institute, Tehran, Iran

3 Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran,

4 CAPS and the Institute for Global Health, University of California, San Francisco, USA


Background: Mycobacterium tuberculosis can be transmitted via aerosols in hospital wards and affect medical students as well as other hospital personnel. This study aimed to assess the changes of tuberculin skin test in medical students compared to pharmacy students during their education. Materials and Methods: This was a natural multiple cohort study performed in the medical education system to assess the rates of TST conversion among students. Tuberculin skin tests were performed on 212 students, including 100 pharmacy students and 112 medical students before the initiation of their clinical rotations and repeated 36 months later after their exposure to hospital wards. Participants completed self-administered questionnaires. Results: Tuberculin skin test (TST) conversion in medical and pharmacy students was 18.1% and 4.3%, respectively during the years 2003 and 2006. Although there was no significant difference between positive TST of the two groups at baseline, a significant difference (P=0.005) was observed after their exposure to hospital wards. There were no significant correlations between TST conversion and age or gender of students. Conclusion: Exposure of medical students to tuberculosis during their education is substantial in Iran and more attention should be paid to prevention strategies in medical students prior to and during their clinical training. (Tanaffos 2009; 8(4): 33-36)