Non-Specific Effects Of Vaccination
Is diphtheria-tetanus-pertussis (DTP) associated with increased female mortality? A meta-analysis testing the hypotheses of sex-differential non-specific effects of DTP vaccine.
In seven studies of BCG-vaccinated children, DTP vaccination was associated with a 2.54 (95% Cl 1.68- 3.86) increase in mortality in girls (with no increase in boys [ratio 0.96, 0.55-1.68]). The ways in which the female and the male immune systems may respond differently to vaccinations in infants are only beginning to be studied.
Peter Aaby, Henrik Ravn, Ane B. Fisker, Amabelia Rodrigues, and Christine S. Benn; Transactions of the Royal Society of Tropical Medicine and Hygiene. 2016 Dec; 110(10): 570–581.doi: 10.1093/trstmh/trw073.
Ten years ago, we formulated two hypotheses about whole-cell diphtheria-tetanus-pertussis (DTP) vaccination: first, when given after BCG (bacille Calmette-Guerin, is a vaccine for tuberculosis), DTP increases mortality in girls and, second, following DTP there is an increase in the female/male mortality rate ratio (MRR). A recent review by WHO found no convincing evidence that DTP increases mortality in females. Now, ten years later, we have tested the two hypotheses using studies from before, but also those published since formulation of the hypotheses. All studies published after the formulation of the hypotheses of the association of DTP with increased mortality.
The introduction of diphtheria-tetanus-pertussis vaccine and child mortality in rural GuineaBissau: an observational study.
The MR (mortality rate) was 1.81 (95% Cl: 0.95, 3.45) for the first dose of DTP and 4.36 (95% Cl: 1.28, 14.9) for the second and third dose
Aaby P, Jensen H, Gomes J, Fernandes M, Lisse IM. International Journal of Epidemiology. 2004 Apr;33(2):374-80.
Prior to the introduction of vaccines, children who were absent at a village examination had the same mortality as children who were present. During 1984-1987, children receiving DTP at 2-8 months of age had higher mortality over the next 6 months, the mortality rate ratio (MR) being 1.92 (95% CI: 1.04, 3.52) compared with DTP-unvaccinated children, adjusting for age, sex, season, period, BCG, and region. The MR was 1.81 (95% CI: 0.95, 3.45) for the first dose of DTP and 4.36 (95% CI: 1.28, 14.9) for the second and third dose. BCG was associated with slightly lower mortality (MR = 0.63, 95% CI: 0.30, 1.33), the MR for DTP and BCG being significantly inversed. Researchers found in low-income countries with high mortality, DTP as the last vaccine received may be associated with slightly increased mortality. Since the pattern was inversed for BCG, the effect is unlikely to be due to higher-risk children having received vaccination. The role of DTP in high mortality areas needs to be clarified.