Tuberculin sensitivity and skin lesions in children after vaccination with two batches of BCG vaccine.

ABSTRACT

BCG is one of the vaccines used, as control arm, in an ongoing large scale comparative leprosy vaccine trial in South India. The objective of the present study was to examine, in the local population, the sensitizing ability, as measured by skin test reactions to tuberculin, and reactogenecity, in terms of skin lesions at the site of vaccination, for the two batches of BCG vaccine used in the above trial. The study was undertaken in 816 tuberculin-negative, previously not vaccinated school children, aged five to 14 years. Each child received one of the two batches of BCG vaccine or normal saline (control), by random allocation. At 12 weeks from vaccination, character and size of local response, at the vaccination site, were recorded. At the same time, the children were retested with tuberculin and post-vaccination reactions to the test were measured after 72 hours. At three years after vaccination all available children were re-examined for the presence and size of BCG scar at the site of vaccination. It was found that healing of vaccination lesions was uneventful, with both batches of BCG. The mean size of the lesion was similar for the two batches, the overall mean being 6.3 mm. The mean size of post-vaccination tuberculin sensitivity increased with age, and it was 14.5 mm and 15.6 mm. The sensitizing effect attributable to the vaccine was 11 mm and 12 mm, for the two batches of BCG respectively. This study showed that the two batches of BCG, in a dose of 0.1 mg, used in the ongoing leprosy vaccine trial were acceptable in terms of vaccination lesion and were highly satisfactory in terms of development of hypersensitivity.