A new study published today in JAMA Network Open shows 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 US infants, but it also causes severe and serious illnesses in adults, especially those 75 and older.
The group used data from the RSV Hospitalization Surveillance Network (RSV-NET), which captures RSV-associated hospitalizations in 58 counties in 12 states — approximately 8% of the US population. The authors estimated the burden of RSV across seven seasons, 2016-2017 through 2022-2023.
In total during the seven seasons, there were 16,575 RSV-associated hospitalizations in adults (median age, 70). Fifty-eight percent of those hospitalized for RSV were women.
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 (95% confidence interval [CI] 33.4 to 91.5) per 100,000 adults in 2016 to 2017 to 76.2 (95% CI, 55.2 to 122.7) per 100,000 adults in 2017 to 2018.
Adults 75 and up most at risk
Adults ages 18 to 49 were hospitalized less frequently than adults 75 and older. For all outcomes, the 2017-2018 season carried the highest burden of severe illness, with 8,620 in-hospital deaths (95% CI, 6,220 to 14,090).
The burden of RSV-associated hospitalizations in older adults was comparable to the burden of influenza-associated hospitalizations during milder influenza seasons
"The burden of RSV-associated hospitalizations in older adults was comparable to the burden of influenza-associated hospitalizations during milder influenza seasons," the authors said.
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.
"These rates suggest a high burden of severe RSV disease, with an estimated 123,000 to 193,000 hospitalizations, 24,400 to 34,900 ICU admissions, and 4,680 to 8,620 in-hospital deaths occurring annually among US adults, although there was a considerable amount of uncertainty surrounding these estimates," the authors wrote.
The 2023-2024 season marked the first season an RSV vaccine was available in the United States for adults over 60 at risk for severe outcomes and all adults 75 and older. The single-dose vaccine has been recommended by the Centers for Disease Control and Prevention.
"Given the large numbers of potentially vaccine-preventable hospitalizations and deaths associated with RSV, increasing vaccine coverage among adults at highest risk could reduce associated hospitalizations and severe clinical outcomes," the authors concluded.
