Evaluation of non-specific effects of infant immunizations on early infant mortality in a southern Indian population
Moulton, L.H.; Rahmathullah, L.; Halsey, N.A.; Thulasiraj, R.D.; Katz, J.; Tielsch, J.M.
Tropical Medicine and International Health Tm and Ih 10(10): 947-955
2005
ISSN/ISBN: 1360-2276 PMID: 16185228 DOI: 10.1111/j.1365-3156.2005.01434.xDocument Number: 256252
The aim of this study was to assess the relationship between receipt of routine childhood immunizations and infant mortality before 6 months of age. This was an observational study of 10,274 infants, in a randomized trial of vitamin A supplementation, who received the study dose and survived to at least 1 week of age. The primary outcome was mortality before 6 months of age, analysed in Cox regression models as a function of vaccine receipt and gender. Receipt of Bacille Calmette Guerin (BCG) or diphtheria, tetanus, polio (DTP) vaccine was associated with significant reductions of one-half to two-thirds of mortality hazards; among girls, those who received both BCG and DTP experienced higher mortality than those who received only one of the two vaccines (hazards ratio 2.4; 95% confidence interval 1.2-5.0). The reduced mortality rate associated with receipt of BCG or DTP may be due to both biological and selection factors; the analyses regarding the combined effect of these vaccines and gender need to be replicated in other settings.