RSV Disease Severity Comparable to Unvaccinated COVID-19, Flu: Daily Dose

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Patient Care brings primary care clinicians a lot of medical news every day—it’s easy to miss an important study. The Daily Dose provides a concise summary of one of the website's leading stories you may not have seen.

Last week, we reported on findings from a study published in JAMA Network Open that examined disease severity among adults hospitalized with respiratory syncytial virus (RSV) and compared it with the severity of COVID-19 and influenza by vaccination status.

The study

For the prospective cohort study, researchers enrolled individuals aged 18 years and older admitted to any of the 25 hospitals in 20 states participating in the Investigating Respiratory Viruses in the Acutely Ill (IVY) network with a laboratory confirmed diagnosis of RSV, SARS-CoV-2, or influenza between February 1, 2022, and May 31, 2023. Data analysis took place from August to October 2023.

Researchers compared the severity RSV disease with COVID-19 and influenza severity, stratified by COVID-19 and flu vaccination status, for clinical outcomes that included the composite of invasive mechanical ventilation (IMV) and in-hospital death.

The final cohort numbered 7998 with 6.1% (484) hospitalized with RSV, 80% (6422) with COVID-19, and 13.7% (1092) with influenza.

The findings

According to the study results, among those hospitalized with RSV, 12% required IMV or died compared with 14.1% of unvaccinated individuals with COVID-19 and 9.2% of vaccinated persons with COVID-19.

Among participants with influenza, IMV or death occurred in 10.3% of those unvaccinated against the virus and among 5.1% of those who were vaccinated.

The adjusted odds of IMV or in-hospital death did not differ significantly among individuals admitted for RSV and those unvaccinated with COVID-19 (aOR, 0.82; 95% CI, 0.59-1.13; P = .22) or unvaccinated with influenza (aOR, 1.20; 95% CI, 0.82-1.76; P = .35). However, the researchers found the odds of IMV or death were significantly elevated among individuals hospitalized with RSV when compared with vaccinated adults with COVID-19 (aOR, 1.38; 95% CI, 1.02-1.86; P = .03) or with flu (aOR, 2.81; 95% CI, 1.62-4.86; P < .001).

Authors' comment

"These findings suggest that before RSV vaccine introduction in the US, RSV disease was at least as severe as COVID-19 or influenza among unvaccinated patients and more severe than COVID-19 or influenza among vaccinated patients hospitalized with those diseases."

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