Field evaluation of trivalent oral polio vaccine efficacy in Madras city--a case control study.

Evaluation of Trivalent Polio Oral Vaccine efficacy under field conditions was carried out, in Madras city. Relative risk of provocative paralysis by IM injection was also studied. The study includes 52 cases and 104 age and sex matched control cases. Vaccine Efficacy (VE) was found to be 75 per cent and 95 per cent by matched pair analysis with control Group. I and II respectively and 87 per cent (95 per cent confidence limits between 90 and 97 per cent) by triplet analysis. The relative risk of giving injection during the prodromal stage in provoking paralysis was found to be 18, 10 and 13, by matched and triplet analysis respectively.