HIV, BCG and TB in children: a case control study in Lusaka, Zambia.

Even before the onset of the HIV epidemic, studies reported large variations in the protective effect of BCG against TB. The current HIV/AIDS epidemic has increased the incidence of tuberculosis in many countries in sub-Saharan Africa. Thus, local estimates of the effectiveness of BCG are needed which take prevalence of HIV into account for planning strategies for vaccination and TB control programmes. A case control study was conducted in Lusaka, Zambia. The study included 116 TB cases and 154 hospital controls. Eighty-eight per cent of controls had BCG scars compared to 77 per cent of the cases. BCG was not associated with TB in HIV positive children (OR 1.0, 95 per cent CI 0.2, 4.6). However, there was 59 per cent protective effect (OR 0.41, 95 per cent CI 0.18, 0.92) in HIV negative children. The results also suggest an eight times higher risk of TB in HIV positive children.