UCSF

INTRODUCTION: Biannual (ie, every 6 months) mass drug administration of azithromycin has reduced childhood mortality in Niger, but its effects on specific respiratory pathogens are not fully elucidated. METHODS: Across 2 years of the Macrolides Oraux pour Réduire les Décès avec un Oeil sur la Résistance (MORDOR) study in Niger, we evaluated 1468 nasopharyngeal swabs from children who presented for care with respiratory symptoms. Swabs were tested by quantitative PCR using a customised TaqMan Array Card that included assays for 19 respiratory pathogens. RESULTS: Nasopharyngeal detection of Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae was common in both azithromycin and placebo communities. The prevalence was reduced in children from azithromycin communities for just two pathogens: Bordetella pertussis and H. influenzae type b (Hib). These children had a 49% and 65% reduction in the prevalence of B. pertussis and Hib in nasopharyngeal swabs, respectively, compared with children from the control communities (prevalence ratios 0.51, 95% CI 0.35, 0.75; and 0.35, 95% CI 0.17, 0.71). CONCLUSIONS: Biannual administration of azithromycin to communities in Niger was associated with lower prevalence of B. pertussis and Hib compared with placebo. These reductions may explain some of the childhood mortality benefit of azithromycin. TRIAL REGISTRATION NUMBER: NCT02048007.