Interpretation of tuberculin reactions in revaccinated children is somewhat controversial among paediatricians. In this study,
the effect of the number of BCG vaccines on tuberculin reactivity is evaluated. In 2810 healthy children aged 7 to 14 years
with purified protein derivative (PPD) testing. Children were grouped according to the concordance of the number of the reportedJdocumented
vaccinations to the number of scars. Group 1 and 2 comprised of children 7 to 10 years of age and 11 to 14 years of age respectively,
who had non-concordant scar numbers, and Group 3 and 4 included 7 to 10 and 11 to 14 years old children with concordant scar
numbers. Mean tuberculin induration sizes were 8.0±5.7 mm for Group 1,10.6 ± 4.9 mm for Group 2, 9.8 ± 4.9 mm for Group 3
and 10.9 ± 4 mm for Group 4. As the time interval after the last dose of vaccination increased, mean induration sizes decreased
in Group 1 and Group 3. In contrast, the mean reaction sizes of Group 2 and Group 4 showed a positive correlation with the
period after the last dose of vaccine.
It seems advisable that an induration size> 15 mm should not be attributed to BCG vaccination in countries with a high tuberculosis
infection prevalence and routine BCG revaccination policies. A detailed investigation for tuberculosis infection and disease
should be performed in those cases.
Key words BCG revaccination - Tuberculin reactivity.