The prevalence of tuberculous infection in the 6- to 7-year-old schoolchild population in Albacete

Abstract

To analyze the prevalence of tuberculosis infection, tuberculin tests were given to 3,292 elementary school children in the first and second grades in the environs of Albacete (Spain) in 1992. There were 1,532 children aged 6 (122 vaccinated with BCG) and 1,760 children aged 7 (162 vaccinated); 51 children tested positive (20 who had been vaccinated and 31 who had not been). The prevalence of infection was 0.78% at 6 years of age and 1.25 at 7 years of age in non vaccinated children, a rate similar to that found by earlier national surveys. One case of active pulmonary tuberculosis was identified. Inclusion of the 8.6% who had been vaccinated caused significant distortion of the initial prevalences. The annual rate of infection, estimated based on an annual decline of 4%, was 0.143 %. Differences in tuberculosis infection by family socioeconomic level, as indicted by level of parental studies or place of residence, were not statistically significant, although we did observe a slightly greater rate among children living in poorer areas and with parents with only elementary school education. Our results confirm a downward trend in the prevalence of tuberculosis infection in the population studied, as well as the importance of carrying out this type of survey to provide a reference for active control and for taking an active stand.