[Prevalence of tuberculosis infection in BCG-vaccinated and unvaccinated Mediterranean schoolchildren]

To determine the prevalence of tuberculous infection in schoolchildren in the province of Malaga, Spain, and to evaluate its relation to sociodemographic variables.

Tuberculin skin tests were used to screen 6-year-olds in their first year of primary school in this cross-sectional study of the prevalence of infection, with calculation of 95% confidence interval (CI). Children who had not been vaccinated against tuberculosis at birth were considered to have a positive test result if they had an induration of >or=5 mm. Those who had received bacillus Calmette-Guerin (BCG) vaccination at birth were considered to have a positive test result if they had an induration size of >10 mm or >15 mm, depending on whether they came from a country with a high or low prevalence of tuberculosis, respectively.

The prevalence of infection in the group of unvaccinated children was 1.16% (95% CI, 0.69%-1.63%). No statistically significant differences were found for any of the sociodemographic variables analyzed. The prevalence of infection in the BCG-vaccinated children was 6.66% (95% CI, 5.55%-7.77%).

The prevalence of tuberculosis infection in our area is slightly higher than that reported after other studies conducted in Spain. This could indicate that tuberculosis continues to be a public health problem in the province of Malaga. Infection in the subgroup of BCG-vaccinated children, however, was lower than that observed in studies of immigrants in Spain who had been immunized at birth. This is probably because the majority of immigrants in our area come from countries with a low incidence of tuberculosis.