Each year, up to 193,000 adults in the United States are hospitalized with respiratory syncytial virus, with those aged 75 years and older facing the highest risks for severe outcomes, including intensive care unit admissions and in-hospital deaths, according to a recent study.

Before the 2023 introduction of a respiratory syncytial virus (RSV) vaccine, RSV was associated with morbidity and mortality among U.S. adults, particularly those aged 75 years and older. Using data from the RSV Hospitalization Surveillance Network (RSV-NET), a cross-sectional study, published in JAMA Network Open, analyzed RSV-associated hospitalizations from October 2016 to September 2023. RSV-NET’s population-based surveillance included 16,575 adults aged 18 years or older with laboratory-confirmed RSV infections, covering approximately 8% of the U.S. population.

The estimated annual burden of RSV-related hospitalizations ranged from 123,000 to 193,000. Adults aged 75 years or older experienced hospitalization rates as high as 411.4 per 100,000 during peak seasons, accounting for 45.6% of all RSV hospitalizations, 38.6% of intensive care unit (ICU) admissions, and 58.7% of in-hospital deaths. Annual ICU admissions ranged from 24,400 to 34,900, while RSV-associated in-hospital deaths ranged from 4,680 to 8,620. Adults aged 75 years or older accounted for a high proportion of RSV-associated in-hospital deaths.

Testing practices for RSV are limited, with only 43.5% of adults hospitalized with acute respiratory illness tested for RSV, which may have underestimated the true burden. Hospitalization rates and clinical outcomes in this population indicated that RSV-associated morbidity and mortality are comparable to those of influenza in milder flu seasons. The findings suggested that RSV vaccination in older adults, particularly those aged 75 years and older or at high risk, could impact RSV-associated hospitalizations, ICU admissions, and mortality.

Full disclosures can be found in the published study.