Comparative skin testing with PPD tuberculin, Mycobacterium avium and M. scrofulaceum sensitin in schoolchildren in Saudi Arabia

Abstract Setting: Jizan region, Saudi Arabia. Objective: To test methodology for studies of tuberculin sensitivity and effectiveness of BCG vaccination programme. Design: School children (n = 315) aged 6–12 years simultaneously tested intradermally with PPD tuberculin RT23, 2TU and 0.1 μg Mycobacterium avium or M. scrofulaceum sensitin. Presence of BCG scar as evidence of previous BCG vaccination. Cervical lymph nodes palpated. Results: BCG coverage was 75%. The prevalences of positive reactions (induration ⪰ 6mm) were higher among children with than without scar. Prevalences of positive reactions to PPD and M. scrofulaceum sensitin were higher among girls than boys. In children with scar, the mean size of positive reactions to PPD was larger among girls than boys, and the prevalence of positive reactions was smaller in this group among children with than without palpable cervical lymph nodes. The sizes of reactions both to M. avium and to M. scrofulaceum sensitin were correlated to the size of the tuberculin reactions. Previous admission to hospital was reported less often by children with than without scar. Conclusions: The technique applied and training of staff was satisfactory. In further studies, however, we will apply three simultaneous tests to each person.