Top 5 RSV Content of 2025

Developments in the respiratory syncytial virus (RSV) space were dominated in 2025 by studies showing the widespread benefits of vaccination among older adult patients, infants, and neonates. Among older individuals, studies showed that thousands of deaths and cases of serious respiratory infection were prevented, and among children, both nirsevimab and clesrovimab, approved in July 2023 and June 2025, respectively, provide reliable options to safeguard these younger patients during their first viral season.

Here are the top 5 RSV articles on AJMC.com for 2025.

5. Boosting RSV Vaccination in Older Adults Could Save Thousands

From October, this article touted the benefits of RSV vaccination in adults 60 years and older, highlighting prevention by way of fewer cases of lower respiratory tract disease (LRTD), hospitalization, and deaths over the 5-year period from August 2023 through July 2028. Incorporating use or no use of the adjuvanted RSVPreF3 vaccine, a team of researchers utilized a multicohort Markov model that estimated the potential public health impact of RSV vaccination. The model’s results show that uptake of the vaccine by 13.4 million older US adults may play a prominent role in preventing 700,000-plus cases of RSV-related LRTD and 6025 deaths. RSV vaccine recommendation was updated in June 2024 to suggest that adults 75 years and older, and those aged 60 to 74 years at increased risk for severe disease, receive a single dose of an approved RSV vaccine.

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4. Real-World Data Show Preventive Nirsevimab Reduces Infant RSV Hospitalizations

Nirsevimab (Beyfortus; Sanofi), a long-acting monoclonal antibody, should continue to be recommended to prevent RSV-associated hospitalization in infants, according to findings from a study that evaluated its effectiveness against this outcome among infants 8 months and younger. For the 2024-2025 RSV season, data on 409,723 infants born between February 1, 2024, and January 31, 2025, were analyzed; of these infants, 47.5% received nirsevimab. Those who were vaccinated against RSV had a 0.4% hospitalization rate vs 1.2% in those who were not. This result equated to an unadjusted HR of 0.29 and an adjusted HR of 0.23, for 71% and 77% lower risks, respectively, of RSV-associated hospitalization.

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3. Infant RSV Hospitalization Rates Drop in First Season With Widespread Preventive Product Use

Compared with pre–COVID-19 pandemic seasons, the 2024-2025 RSV season was witness to a significantly lower total hospitalization rate of infants aged 0 to 7 months, per the CDC’s Morbidity and Mortality Weekly Report. Researchers explained that the widespread use of both the maternal RSV vaccine and nirsevimab contributed to the positive result. They compared outcomes from the 2018-2020 seasons with the 2024-2025 season using the RSV-Associated Hospitalization Surveillance Network and the New Vaccine Surveillance Network, among 3 pediatric age groups: 0 to 7 months, 8 to 19 months, and 20 to 59 months. Overall, there were 11,681 RSV-related hospitalizations during the 2018-2020 seasons vs 6708 RSV-related hospitalizations during the 2024-2025 season, with lower RSV-associated hospitalization rates per 1000 children in the 2024-2025 season.

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2. Nirsevimab, RSVpreF Saw High Uptake With No Preterm Risk for RSVpreF

First approved in July 2023 and August 2023, respectively, nirsevimab and the RSV prefusion F vaccine (RSVpreF) both had high total uptake among their targeted patient populations of infants and pregnant individuals. The study evaluated results for 647 pregnant individuals who were eligible for the RSVpreF vaccine and had reached 32 to 36 weeks’ gestation between October 15, 2023, and January 31, 2024; their infants were eligible for vaccination if the birth parent had not themselves been vaccinated at least 2 weeks before delivery. Older maternal age, nulliparity status, having private insurance, being of a non-Hispanic ethnicity, and having received another vaccine (eg, flu, COVID-19, tetanus-diphtheria-pertussis) were all associated with high RSVpreF vaccine uptake (64.0%). Of the 70.1% of infants eligible for nirsevimab, 40.4% had been born to parents who declined routine prenatal vaccines, including infant hepatitis B vaccination.

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1. FDA Approves Clesrovimab to Prevent RSV in Infants During First Season

With the June approval of clesrovimab (Enflonsia; Merck), infants and neonates born during or entering their first RSV season received a second immunization option against the dangerous lower respiratory tract disease. The FDA based its decision on data from the phase 2b/3 CLEVER trial (NCT04767373), results of which showed a 60.5% reduced incidence of RSV-associated medically attended lower respiratory infections and an 84.3% reduced hospitalization rate. Of the new vaccine, Octavio Ramilo, MD, chair of the Department of Infectious Diseases at St. Jude Children’s Research Hospital and trial investigator, said, “Enflonsia combines dosing convenience with strong clinical data showing significant reductions in RSV disease incidence and hospitalizations, making it a promising new intervention to help protect infants from RSV.”

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