Though hospitalizations for respiratory syncytial virus (RSV) are less common than those for flu or COVID-19, they are more severe and more likely to occur in adults ages 75 and older, according to new data published today in Morbidity and Mortality Weekly Report.
The study looked at adult hospitalization for RSV in the United States from February 2022 to May 2023. A total of 5,784 adults aged 60 years or older hospitalized with acute respiratory illness and laboratory-confirmed RSV, SARS-CoV-2, or influenza infection were prospectively enrolled in the study conducted at 25 US hospitals.
Severity of illness was based on the following outcomes: standard-flow oxygen therapy, high-flow nasal cannula (HFNC) or noninvasive ventilation (NIV), intensive care unit (ICU) admission, and invasive mechanical ventilation (IMV) or death.
Overall, 304 (5.3%) adults were hospitalized with RSV, 4,734 (81.8%) with COVID-19, and 746 (12.9%) with influenza. The median age of hospitalized RSV patients was 72 years, compared to 74 for COVID-19 and 71 for influenza.
Greater odds of respiratory support needed
The odds for all outcomes were higher for RSV patients compared to COVID-19 or influenza. Patients hospitalized with RSV were more likely than hospitalized COVID-19 patients or hospitalized influenza patients to receive standard-flow oxygen (adjusted odds ratio [aOR], 2.97 [COVID-19] and 2.07 [influenza]) and HFNC or NIV (aOR, 2.25 [COVID-19] and 1.99 [influenza]) or to be admitted to an ICU (aOR, 1.49 [COVID-19] and 1.55 [influenza]).
"Clinical outcomes in patients hospitalized with RSV were worse than those among patients hospitalized with COVID-19 or influenza.
The odds of the composite outcome of IMV or death between patients hospitalized with RSV and patients hospitalized with COVID-19 was similar but much higher for RSV compared to influenza.
"Clinical outcomes in patients hospitalized with RSV were worse than those among patients hospitalized with COVID-19 or influenza," the authors said. "Because RSV disease is less common than COVID-19 or influenza disease among hospitalized patients, clinicians might be less aware of RSV as a serious respiratory pathogen in older adults."
In June 2023, the Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices recommended RSV vaccination for adults aged 60 years and older. In the United States, an estimated 60,000 to 160,000 RSV-associated hospitalizations and 6,000 to 10,000 RSV-associated deaths occur each year among adults aged 65 and older.
Canadian study shows increase in RSV hospitalizations post pandemic
Another group likely to be hospitalized for RSV is infants under age 6 months. A new study from Canada published this week in JAMA Network Open found an increase in pediatric RSV hospital admissions during the 2021 to 2022 cold and flu season but not an increase in disease severity.
The study looked at RSV trends across five seasons (2017-2018 to 2021-2022) at 13 pediatric tertiary care centers. RSV hospitalizations for children 0 to 16 years were considered.
Across all seasons, 60.8% of hospitalizations were among children aged less than 6 months.
There were 58 hospitalizations reported in 2020-2021, followed by 3,170 hospitalizations in 2021-2022, the authors said.
"We observed an overall increase in pediatric RSV–associated hospitalizations in Canada after the first year of the COVID-19 pandemic, beginning in the summer of 2021," the authors concluded. "This resurgence of RSV infections was likely associated with reduced population-level immunity caused by the absence of infections in the previous year, combined with children’s reengagement in social activities and the relaxing of other COVID-19 public health measures."
