In a recent study analyzing severe outcomes among vaccinated adults, RSV was found to pose a greater risk than both COVID-19 and influenza, particularly in terms of necessitating Invasive Mechanical Ventilation (IMV) or death.

Investigators looked at 7,998 adults, a median age of 67 and about half female. 484 people (6.1%) were hospitalized with RSV, 6,422 (80.3%) with COVID-19, and 1,092 (13.7%) with influenza. 12.0% of those with RSV either needed IMV or died. This outcome compares to 14.1% of unvaccinated COVID-19 patients 9.2% of vaccinated ones, and 10.3% of unvaccinated and 5.1% of vaccinated influenza patients. When adjusting the data for comparison, people with RSV had similar chances of IMV or death as unvaccinated COVID-19 (odds ratio [OR] 0.82) or influenza patients (OR 1.20), odds were significantly higher compared to vaccinated COVID-19 (OR 1.38) and influenza patients (OR 2.81).

“This evaluation of RSV epidemiology during a period of endemic COVID-19 demonstrates that RSV is a serious respiratory infection in adults, and especially older adults,” according to the investigators. “Newly approved RSV vaccines for adults aged 60 years and older have the potential to reduce this severity, similar to attenuation of disease severity achieved with COVID-19 and influenza vaccination, as previously reported and also observed in this analysis

This prospective cohort study enrolled adults 18 and older who were hospitalized due to acute respiratory illnesses confirmed by laboratory tests to be either RSV, SARS-CoV-2, or influenza. Participants were recruited from 25 hospitals across 20 states in the US, from February 1, 2022, to May 31, 2023. The analysis of the data took place between August and October 2023.

“By stratifying our COVID-19 and influenza populations by vaccination status, we demonstrate that critical outcomes of ICU admission and IMV or death occurred in a similar proportion of unvaccinated adults hospitalized with RSV compared with unvaccinated adults hospitalized with COVID-19 or influenza,” according to the investigators. “This analysis highlights the importance of considering RSV vaccination in older adults, supported by clinical trials showing moderate to high efficacy of RSV vaccination against lower respiratory tract disease, which could lead to a reduction in severe disease outcomes.”

This analysis has limitations. It may be biased towards detecting RSV more frequently in severely ill patients who are more likely to undergo testing in hospitals. Among 6,759 adults hospitalized with acute respiratory illness and not initially tested for RSV, only 34 (0.5%) were later found to have RSV, suggesting that the number of missed cases is likely low. The study does not account for the potential impact of antiviral and immunomodulatory treatments on disease severity. Comparisons across virus groups did not adjust for treatments, indicating that reported severity levels for COVID-19 and influenza might include both treated and untreated patients.

In conclusion, the findings from this study, conducted before implying adult RSV vaccine guidelines, reveal that RSV disease severity in hospitalized adults matches that of unvaccinated patients with COVID-19 or influenza and surpasses the severity seen in those vaccinated against these viruses. These results highlight the critical need to consider the severity of RSV disease in adults as policies around RSV vaccination evolve.

Reference

Surie D, Yuengling K, DeCuir, et. al. Severity of Respiratory Syncytial Virus vs COVID-19 and Influenza Among Hospitalized US Adults. JAMA Network. Published April 4, 2024. Accessed April 5, 2024. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2817146?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=040424