RSVpreF Vaccine Is Well-Tolerated in Adults, Demonstrating Favorable Safety Profile

New study findings from a post hoc analysis provide a comprehensive review of safety data for the bivalent respiratory syncytial virus prefusion F (RSVpreF, Abrysvo; Pfizer) vaccine, including data from 8 clinical trials involving over 46,000 immunocompetent adults. The study authors, who published their findings in Vaccines, noted that the most common adverse events for the vaccine were localized reactions, including injection site pain, fatigue, and headache; however, it was well tolerated with a favorable safety profile in adults compared with placebo.¹

Image credit: Cynthia | stock.adobe.com

RSV Incidence in Older Adults

RSV is estimated to impact nearly 64 million individuals globally each year, accounting for up to 10,000 deaths in individuals aged 65 years and older. In the United States, RSV relates to 110,000 to 180,000 hospitalizations each year in individuals aged 50 years and older. This population group is among the individuals considered high risk for severe RSV-associated illness, which could worsen conditions like asthma, chronic obstructive pulmonary disease, or heart failure, leading to hospitalization or fatal outcomes, according to the CDC.²

RSVpreF Approval

As a bivalent vaccine, RSVpreF targets both RSV-A and RSV-B strains. The vaccine received FDA approval in June 2023 to prevent lower respiratory tract disease (LRTD) caused by RSV in individuals 60 years of age and older. Following the initial approval, the FDA approved RSVpreF in October 2024 for RSV LRTD for individuals aged 18 through 59 years, marking the vaccine as the first and only RSV immunization designated for adults younger than 50 that are at increased risk for LRTD.^1,3,4

RSVpreF was evaluated in several clinical studies and consistently demonstrated an acceptable safety and tolerability profile. However, the study authors noted that because individual trials were not large enough to identify rare safety events, a comprehensive analysis on pooled data is beneficial, leading them to assess the vaccine’s safety and how the body reacts to it in adults aged 18 years and older.¹

Post Hoc Study Design and Results

Researchers included 8 clinical trials in the analysis, including 5 in male and non-pregnant female participants aged 18 through 59 years and 1 in male and female participants 60 years and older. Among the younger group, 5418 participants were given the RSVpreF vaccine, and 4499 received a placebo. In the older group, 18,661 participants were given the RSVpreF vaccine, and 18,335 received a placebo.¹

The results from the comprehensive analysis of both clinical trial data demonstrated that the RSVpreF vaccine has an acceptable safety profile in adults. Additionally, the findings suggest that there is a need to protect healthy young adults from RSV, as the focus is commonly on immunocompromised individuals. For non-high-risk adults aged 18 to 59, the treatment for RSV is generally limited to supportive care. Additionally, because natural RSV infection doesn't provide long-lasting immunity, individuals can be reinfected, and the true incidence of RSV in adults is often underestimated due to inconsistent testing and varied case definitions.¹

Further results found that the most common adverse events from the RSVpreF vaccine were injection site pain, fatigue, and headache. The reactions were typically mild to moderate and were often reported with many other adult vaccines, like those for COVID-19, influenza, and hepatitis. Younger participants under 60 and females tended to report more frequent adverse effects compared with older adults and males.¹

REFERENCES

1. Ilangovan, K., Radley, D., Patton, M., Shittu, E., Lino, M. M., Goulas, C., Swanson, K. A., Anderson, A. S., Gurtman, A., & Munjal, I. (2025). Integrated Analysis of the Safety Experience in Adults with the Bivalent Respiratory Syncytial Virus Prefusion F Vaccine. Vaccines, 13(8), 827. https://doi.org/10.3390/vaccines13080827

2. RSV in Adults. CDC. News release. Updated July 8, 2025. Accessed August 7, 2025. https://www.cdc.gov/rsv/adults/index.html

3. Pharmacy Times staff. FDA Approves Abrysvo to Prevent Respiratory Syncytial Virus in Older Adults. Pharmacy Times. June 1, 2023. Accessed August 22 2025. https://www.pharmacytimes.com/view/fda-approves-abrysvo-to-prevent-respiratory-syncytial-virus-in-older-adults

4. Ferruggia K. FDA Approves Abrysvo to Treat Adults 18 to 59 Years of Age at Increased Risk for RSV. Pharmacy Times. October 23, 2024. Accessed August 22, 2025. https://www.pharmacytimes.com/view/fda-approves-abrysvo-to-treat-adults-18-to-59-years-of-age-at-increased-risk-for-rsv