Prevalence of positive tuberculin skin test and associated factors among Makerere medical students,Kampala, Uganda

Background

Tuberculosis infection among medical students is thought to be higher than that among comparable groups.

Objectives

To determine the prevalence of positive Tuberculin Skin Test (TST) and associated factors among medical students at Makerere University.

Methods

A-cross-sectional study among randomly selected medical students. Using intra-dermal technique, TST was performed by administering 0.1ml of purified protein derivative. Readings performed after 72 hours and positive TST based on an induration of ≥10mm.

Results

Of 302 students selected to participate, 292 received TST and 288 were analyzed. Of 288 students, 173(60%) were pre-clinical (years 1–3) and 115(40%) clinical (years 4&5). Overall 130 students [45.1%(C.I.39.3–51.1)] had positive TST, not different from one derived from mixture analysis [46.3%(95% Bayesian credibility interval 36.5%–55.8%)]. Positive TST prevalence among pre-clinical was 39.9%(67/173) compared to 53.0%(61/115) among clinical students, OR=1.70,C.I.(1.06–2.74) and increases in a linear pattern with increasing years of study (p=0.002,OR=5.04).

Conclusion

The prevalence of TB infection among medical students was twice higher than that of adults living in the suburbs and higher among those in clinical relative to pre-clinical years suggesting that exposure and infection might be related to clinical work. We recommend urgent institution of infection control measures.