Background: We have proposed the hypothesis that the combination of vitamin A supplementation and diphtheria-tetanus-pertussis (DTP) vaccination may be associated with increased mortality in girls. Recent zinc/folic acid (FA) and iron supplementation trials did not find any beneficial effects on mortality. We reviewed the studies for evidence of a negative interaction between zinc/folic acid/iron and DTP vaccination in girls.
Methods: Based on the published papers, we calculated age- and sex-specific mortality estimates. No vaccination status data were provided.
Results: Both zinc/FA and iron seemed to have a sex- and age-differential effect, the effect being less beneficial in the youngest girls who are most likely to have DTP vaccine as their most recent vaccination.
Conclusions: Like vitamin A, zinc/FA and iron may not benefit the youngest girls. The question is whether this is inherent in girls or due to an interaction with some environmental factor like DTP.