RESPIRATORY syncytial virus (RSV) transmission in U.S. households was examined in a new study that showed young children are the primary drivers of infection, spreading the virus to adults and other household members. The research, conducted from June 2022 to May 2023, followed participants across multiple households, collecting nasal swabs and blood samples weekly to detect RSV cases and analyze transmission patterns.
The study found RSV in 10% of participants and 20% of households, with nearly all (94%) of the initial cases showing symptoms. Secondary transmission—when the virus spread from an initial case to another household member—occurred in 10% of cases within 14 days. The median age of the first infected person was six years, while secondary cases had a median age of 35 years, underscoring that children are the primary transmitters of RSV within households. Notably, 89% of initial cases were in children aged six months to 12 years.
Two key factors significantly increased the risk of RSV transmission: prolonged viral detection (lasting at least one week) and close contact with children under 12 years old.
Researchers also analyzed RSV genomes from 120 samples, identifying two dominant viral lineages—A.d.5.2 and A.d.1. In households with multiple infections occurring within 14 days, the viruses were genetically similar, confirming that these cases were the result of direct household transmission rather than outside exposure.
These findings highlight the critical role of young children in RSV spread and emphasize the need for targeted prevention strategies. With most transmissions originating from infants and children, healthcare professionals should prioritize interventions aimed at limiting household spread, particularly among high-risk populations.
