Trends of tuberculin skin test positivity rate among schoolchildren in Attica, Greece

We sought to estimate the prevalence and temporal trends of tuberculin skin test (TST) positivity rate among schoolchildren, in a suburban area of Attica, Greece. We retrospectively analysed the prevalence of the TST positivity (forearm volar surface induration >10 mm) of schoolchildren, in the catchment area of the public primary healthcare centre of Vari, over a 16-y period (1990-2005). TSTs were performed in the context of a national, government-directed TB screening programme. We retrieved 11,105 records of TSTs performed on children aged 6 and 14 y. These tests referred to 7920 and 2969 BCG unvaccinated and vaccinated children, respectively, as well as 120 children who had close contact with a TB confirmed case, and 6 children with known active or latent TB. The prevalence of TST positivity among BCG unvaccinated children was 2.0% over the whole study period; this figure declined in the second compared to the first half of the study period (2.4% vs 1.4%, p<0.001). The gradual decline in TST positivity among BCG unvaccinated schoolchildren, despite the substantial rise in the number of immigrants in Greece, over our study period, may, at least in part, be attributed to relevant national screening and prevention measures.