A study in Guinea-Bissau (GB) published in the British Medical Journal in December 2000 by Kristensen et al.1 suggested a non-specific effect of routine vaccination that might influence survival in infants, either negatively or positively, depending upon the vaccine. Increased mortality was reported in children vaccinated with DTP in the six months following vaccination. It was suggested that females were more likely to suffer increased mortality. The Global Advisory Committee on Vaccine Safety (GACVS) reviewed this issue and urged WHO to arrange for testing of the hypothesis on different data sets from different countries where vaccination data, death and other factors possibly influencing mortality had been recorded. Following an open call for proposals, WHO funded or co-funded studies in Bangladesh, Burkina Faso, Indonesia and Papua New Guinea.
Analysis of the WHO-sponsored studies is now complete. All the studies show reduced mortality rates in the children vaccinated with all of the vaccines. In particular, the studies showed no negative effect of DTP vaccination and no difference was found between males and females.
The Committee concluded that the evidence is sufficient to reject the hypothesis for an increased non-specific mortality following vaccination.