Association between bacterial microbiota composition and oral vaccine response among Indian infants enrolled in a zinc/probiotic supplementation trial

Oral rotavirus vaccines have consistently proven to be less immunogenic among infants in developing countries. Discrepancies in bacterial microbiota composition may contribute to this trend. To test this hypothesis, we performed a nested case–control study in Vellore, India, in which we sequenced the 16S rRNA gene V4 region of 170 infants who responded serologically or not after two doses of Rotarix delivered at 6 and 10 weeks of age as part of a clinical trial (CTRI/2012/05/002677). Infants received trivalent oral poliovirus vaccine at the same time as each Rotarix dose. We observed no consistent differences in composition or diversity of the 16S bacterial microbiota according to rotavirus seroconversion, although rotavirus shedding was associated with slightly more bacterial taxa pre-vaccination.