Diphtheria-Tetanus-Pertussis (DTP) Vaccine Is Associated with Increased female-Male Mortality. Studies of DTP administered before and after measles vaccine

Background: The third dose of diphtheria-Tetanus-pertussis vaccine (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 (95% confidence interval [CI],. 88-1.57) after DTP1 and increased to 1.66 (95% CI, 1.32-2.09) after DTP3. Following receipt of MV, the F/M MRR declined to 0.63 (95% CI,. 42-.96). In 11 studies the F/M MRR increased to 1.73 (95% CI, 1.33-2.27) when DTP-containing vaccine was administered after MV. Conclusions: F/M MRR increased with increasing doses of DTP. After MV, girls had lower mortality than boys. With DTP after MV, mortality increased again for girls relative to boys. No bias can explain these changes in F/M MRR. DTP does not improve male survival substantially in situations with herd immunity to pertussis and higher F/M MRR after DTP may therefore reflects an absolute increase in female mortality.