Nasopharyngeal microbiota Targeted loci

Live attenuated influenza vaccine (LAIV) alters nasopharyngeal microbiota in adults. LAIV immunogenicity varies across populations for reasons poorly understood, but may be linked to the microbiome. We investigated the impact of LAIV on nasopharyngeal microbiota, and the impact of nasopharyngeal microbiota on LAIV immunogenicity in Gambian children. We conducted a phase IV open label randomised controlled trial in clinically well children aged 24-59 months in The Gambia (NCT02972957). Participants (n=330) were randomised 2:1, stratified by sex, to receive trivalent LAIV at recruitment (day 0 (D0), LAIV group) or after follow-up (day 21, control group) using pre-prepared computer-generated sequence. Primary outcomes were impact of LAIV on microbial communities as determined by 16S rRNA sequencing, and impact of microbiota on LAIV-induced mucosal IgA responses. Secondary outcomes were impact of microbiota on seroconversion, Influenza A Matrix and Nucleoprotein CD4+T-cell responses (MNP), and induction of ex vivo peripheral T follicular helper (Tfh)-like CD4+ cells. Respiratory viral co-infection (asymptomatic) at recruitment, and year of were included as covariates. The trial is closed for recruitment.