Kulkarni H R, Zodpey S P
Department of Preventive and Social Medicine and Clinical Epidemiology Unit, Government Medical College, Nagpur, India.
Public Health. 1999 Nov;113(6):311-3. doi: 10.1016/s0033-3506(99)00187-0.
For this paper we conducted a secondary data analysis to test the hypothesis that a linear trend exists in the protective effect of bacillus Calmette-Guerin (BCG) vaccine against types of leprosy. We used data from two previous case-control studies to perform an unmatched test for linear trend. We observed that both the studies revealed a significant linear trend (P<0.00001). One study that estimated an insignificant protective effect of BCG against paucibacillary leprosy showed a significant departure from linearity. We conclude that, the protective effect of BCG vaccination is differential across severity of leprosy as it brings about a shift in the immune response to a higher level of cell mediated immunity. We recommend that future studies dealing with the protective effect of BCG against leprosy should also conduct an analysis for trend.
