Immunization status and child survival in rural Ghana

Abstract

For three decades the Expanded Programme on Immunization (EPI) has been promoted as one of the key child health interventions in developing countries. Vaccines for six childhood diseases (diphtheria measles pertussis poliomyelitis tetanus and tuberculosis) have been shown to be efficacious in preventing disease-specific morbidity and mortality yet not all commentators are convinced that the EPI reduces all-cause child mortality. Numerous studies have found that measles vaccination programs substantially reduce all-cause child mortality but recent findings from Guinea-Bissau suggest that diphtheria pertussis and tetanus (DPT) vaccine may increase all-cause child mortality. The present study uses 5 years of data from the Navrongo Demographic Surveillance System a longitudinal population registration system in northern Ghana to examine all-cause mortality among vaccinated and unvaccinated children under 5 years of age. The data indicate that coverage by one Bacillus Calmette-Guerin (BCG) shot three sets of polio drops and three DPT shots reduces mortality between ages 4 and 8 months by nearly 90%. Complete coverage by all EPI antigens reduces mortality between ages 9 and 59 months by 70%. BCG polio and DPT vaccines without measles vaccination reduce mortality by 40%. The independent reduction in mortality associated with measles vaccination is 50%. The authors data add to a growing body of evidence that suggests that measles vaccination programs reduce all-cause mortality substantially beyond the proportion of deaths caused by measles. These results indicate a need for further research in developing countries on the all-cause mortality impact of these vaccines in particular DPT vaccine. (authors)