Commentary: Contrary findings from Guinea-Bissau and Papua New Guinea

Abstract

About four years ago a study of routine immunizations in rural areas of Guinea-Bissau suggested that early BCG and measles vaccination (MV) were associated with reduced mortality which was not explained by the prevention of TB or measles but that early diphtheria-tetanus-pertussis (DTP) vaccine was associated with increased mortality. Given the observational design and the potential for bias a precise estimate of these effects could not be established but it was noteworthy that different vaccines had opposite effects. Several studies from Bissau Senegal and Benin have found similar patterns of BCG and MV being associated with lower mortality and DTP with higher mortality. These effects are most marked immediately after vaccination and until the next vaccine is received. When DTP has been the last vaccine received it has been associated with a higher mortality for girls. WHO withdrew high-titre measles vaccine (HTMV) because it was associated with increased female mortality; however the higher mortality may have been because the measles vaccine was followed by DTP vaccine rather than any direct adverse effect of HTMV. (excerpt)