Clinical Research Directory

BCG Revaccination With the Third Dose of Diphtheria-tetanus-pertussis Vaccine and Infant Mortality in Africa

Studies in low-income countries show that vaccines can have important non-specific effects on other infections. Live BCG vaccine can train the immune system and reduce susceptibility to unrelated infections. In contrast, non-live diphtheria-tetanus-pertussis-containing (DTP) vaccine enhances susceptibility in females: DTP vs no DTP is associated with 2-fold higher mortality, and in DTP-vaccinated children, females have higher mortality than males. These effects are seen as long as a vaccine is the most recent vaccine. WHO recommends BCG at birth followed by three DTP vaccines. A metaanalysis based on observational studies has shown that co-administration of BCG+DTP is associated with lower mortality than BCG followed by DTP. The investigators will implement a randomised trial in urban Guinea-Bissau, including 6000 children, to test the hypothesis that an extra dose of BCG given with DTP3 (BCG2+DTP3 vs. DTP3) can: * reduce death and hospital admissions by 25% * reduce the F/M severe morbidity hazard ratio