BACKGROUND: The third dose of diphtheria-tetanus-pertussis (DTP3) is used to monitor immunization programs. DTP has been associated with higher female mortality.

METHODS: We updated previous literature searches for DTP-studies of mortality by sex. We examined the female/male (F/M) mortality rate ratio (MRR) with increasing number of doses of DTP and for subsequent doses of measles vaccine (MV) after DTP and of DTP after MV.

RESULTS: Eight studies had information on both DTP1 and DTP3. The F/M MRR was 1.17 (0.88-1.57) after DTP1 and increased to 1.66 (1.32-2.09) after DTP3. Following receipt of MV the F/M MRR declined to 0.63 (0.42-0.96). In 11 studies the F/M MRR increased to 1.73 (1.33-2.27) when DTP-containing vaccine was administered after MV.

CONCLUSIONS: The F/M MRR increased with increasing doses of DTP. After MV, females had lower mortality than males. If DTP was provided after MV, mortality increased again for females relative to males. No bias can explain these changes in the F/M MRR. DTP does not improve male survival substantially in situations with herd immunity to pertussis and the higher F/M MRR after DTP may therefore reflects an absolute increase in female mortality.