Most infants acquire RSV infection from their siblings. This is what Munywoki et al. found in a household-based prospective cohort study in Kilifi district, Kenya. Households with at least 1 infant and 1 sibling were followed during the course of a RSV epidemic. Frequent nasopharyngeal swabs were collected from all household members, irrespective of RSV related symptoms.
In total 44 households (451 participants) yielded 15 396 nasopharyngeal swabs during study period. Using phylogenetic analysis Munywoki et al. showed that 15 of 28 (53.6%) infant RSV infections were directly related to transmission within their household. In particular school age children strongly contributed to household transmission.
This publication shows that most young infants acquire RSV infection from their siblings suggesting that targeting siblings by a future RSV vaccine or hygiene measures may be an effective strategy to reduce RSV bronchiolitis during infancy.