From the original article: Early diphtheria-tetanus-pertussis vaccination associated with higher female mortality and no difference in male mortality in a cohort of low birthweight children: an observational study within a randomised trial:
What is already known on this topic
What this study adds
- ▶ Adjusted for nutritional status, DTP vaccinated children, particularly girls, had threefold higher mortality between 2 and 6 months of age.
- ▶ Nutritional status was a strong predictor of mortality among boys but not girls.
- ▶ There is a continuing contradiction between studies of DTP from low-income countries and current policy.
"Adjusting for mid upper arm circumference (a surrogate measure of nutritional status), the overall effect for DTP vaccinated children was 2.62 (95% CI 1.34 to 5.09); the death rate ratio was 5.68 (95% CI 1.83 to 17.7) for girls and 1.29 (95% CI 0.56 to 2.97) for boys (p=0.023, homogeneity test). While anthropometric indices were a strong predictor of mortality among boys, there was little or no association for girls."
[If these adjustments are accurate, it seems both girls and boys died at higher than expected rates.--Nass]
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Studied in a different way, Aaby's group found up to a 20-fold increase in female twin mortality after MMR compared to its male twin.
http://www.ncbi.nlm.nih.gov/pubmed/15082642
Int J Epidemiol. 2004 Apr;33(2):367-73.
Divergent female-male mortality ratios associated with different routine vaccinations among female-male twin pairs.
Aaby P1, Jensen H, Rodrigues A, Garly ML, Benn CS, Lisse IM, Simondon F.
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Abstract
BACKGROUND:
Observational studies have suggested that vaccinations have non-specific effects that differ by sex. In the absence of randomized trials, studies of female-male twin pairs would allow us to investigate whether an intervention had sex-specific effects on survival. We therefore examined mortality patterns among female-male twin pairs according to vaccination status. Design We identified female-male twin pairs using the population registers from one urban district and three rural studies from Guinea-Bissau and Senegal and examined the female-male mortality ratio (MR) according to the last vaccine received among pairs in which a death occurred before 18 months of age. As background information, we examined sex- and age-specific mortality patterns in the pre-vaccination era. Subjects In all, 626 female-male twin pairs identified between 1978 and 2000.
RESULTS:
There was no sex difference in mortality for boys and girls in the pre-vaccination era. In the combined analysis of all studies, the female-male MR was 0.25 (95% CI: 0.05, 0.93) for pairs having received Bacille Calmette-Guerin (BCG) as the last vaccine, 7.33 (95% CI: 2.20, 38.3) for pairs having received diphtheria, tetanus, pertussis (DTP) as the last vaccine, and 0.40 (95% CI: 0.04, 2.44) for pairs having received measles vaccine as the last vaccine. The female-male MR varied significantly for BCG compared with DTP (exact test of homogeneity, P < 0.001) and for DTP compared with measles vaccine (exact test of homogeneity, P = 0.001).
CONCLUSION:
Non-specific effects of routine vaccinations are likely to be important and influence sex-specific mortality patterns in areas with high mortality. The effects of vaccines need to be considered in the planning of immunization programmes for low-income countries.
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