Despite widespread use of PCV13, pneumococcal carriage remains high among Gambian infants. We investigated the role of biomass smoke exposure and inflammation in modulating pneumococcal carriage in The Gambia.
Rural Gambian children (n=120) were followed up at regular intervals from birth to two years of age. All infants received PCV13. Pneumococcal carriage was determined by quantitative PCR and inflammation by measuring plasma alpha-1 glycoprotein (AGP). Smoke exposure was self-reported by the mothers. Adjusted random effects regression models were applied to investigate the relationships between pneumococcal carriage, smoke exposure, and inflammation.
Exposure to biomass smoke was significantly associated with a nearly 3-fold increase in the odds of pneumococcal carriage (OR 2.9, 95% CI: 1.13 - 7.5) and, in independent models, a 1/3-log10 increase in pneumococcal load (Coefficient 0.35, 95% CI: 0.11 - 0.59), compared to non-exposure. Inflammation (AGP) was significantly associated with an increased pneumococcal load (Coefficient 0.22, 95% CI: 0.03 - 0.41) in a model unadjusted for smoke exposure. Mediation analysis suggests that there are age, inflammation and smoke exposure interactions that may modify the effects of smoke exposure on pneumococcal carriage.
Biomass smoke exposure may be an important environmental factor driving pneumococcal carriage and loads among PCV-vaccinated Gambian children.