On Nov. 13, 2024, a study published in JAMA Network Open showed that respiratory syncytial virus (RSV) was associated with a substantial burden of hospitalizations, intensive care unit (ICU) admissions, and in-hospital deaths in adults in the years before vaccination was approved for use in the United States. RSV is the leading cause of hospitalization for U.S. infants, but it also causes severe and serious illnesses in adults, especially those 75 and older. 

The data came from the RSV Hospitalization Surveillance Network (RSV-NET), which captures RSV-associated hospitalizations in 58 counties in 12 states — approximately 8% of the U.S. population. carried the highest burden of severe illness, with 8,620 in-hospital deaths. The authors estimated the burden of RSV across seven seasons, 2016-2017 through 2022-2023. 

After removing the 2020-2021 and 2021-2022 seasons, which were disrupted by the COVID-19 pandemic, the authors found hospitalizations ranged from 48.9 per 100,000 adults in 2016 to 2017 to 76.2 per 100,000 adults in 2017 to 2018. Across all seasons, RSV hospitalization was associated with significant use of the ICU, with at least 20% of adult patients requiring intensive care during their hospital stay. Approximately 1 in 25 patients died from RSV annual during hospitalization.