Seasonal variation in the non-specific effects of BCG vaccination on neonatal mortality

The BCG vaccine protects non-specifically against other diseases than tuberculosis. Three randomised controlled trials of early BCG in Guinea-Bissau found a 38% reduction in all-cause neonatal mortality. Little is known about the underlying mechanisms. In Guinea-Bissau, prevalent infectious diseases display distinct seasonality. Revisiting the three trials (>6500 infants) comparing early BCG versus no early BCG in low weight infants on all-cause neonatal mortality over 12 consecutive years, we explored the seasonal variation in BCG’s effect on mortality. In a subgroup of participants, adaptive and innate cytokine responses were measured 4 weeks after randomisation. Consistently over the course of the three trials and 12 years, the effect of BCG on all-cause neonatal mortality was particularly beneficial when administered in November to January, coincident with peaking malaria infections. During these months, BCG was also associated with stronger proinflammatory responses to heterologous challenge. Recent studies have suggested a protective effect of BCG against malaria. BCG may also ameliorate immune-compromising fatal effects of placental malaria in the newborn

BCG vaccine · Environmental health · New guinea · Vaccination · Child Nutrition and Water Access · Demography · History · Immune responses and vaccinations · Medicine · Vaccine Coverage and Hesitancy · Immunology · Pediatrics

• Making sense of emerging evidence on the non-specific effects of the BCG vaccine on malaria risk and neonatal mortality

  Open Access•Quique Bassat, Gemma Moncunill et al.•BMJ Global Health•2020

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