RSVpreF Vaccine Demonstrates Strong Efficacy and Safety Against RSV Infections

Revaccination with the bivalent respiratory syncytial virus (RSV) prefusion F (RSV-preF) vaccination 12 months after initial vaccination was well tolerated and immunogenic in healthy adults, according to a study published in The Journal of Infectious Diseases.

The RSVpreF vaccine is a bivalent prefusion F protein formulation derived from RSV-A and RSV-B strains. Results from a previous phase 1/2 first-in-human study in adults showed that RSVpreF was well tolerated and elicited robust RSV-A and RSV-B neutralizing titers 1 month after vaccination. Clinical trials have demonstrated robust immunogenicity, safety, and efficacy. Information on the persistence of antibody responses and potential revaccination intervals is necessary for recommending bodies and prescribers.

“Therefore, this report presents antibody persistence approximately 12 months after primary dosing and safety and immunogenicity after revaccination with RSVpreF (240 μg) among those participating in the phase 1/2 first-in-human study of 18- to 49-year-olds and 65- to 85-year-olds,” explained Edward Walsh, Infectious Diseases Division, Department of Medicine, Rochester General Hospital and University of Rochester Medical Center in Rochester, New York, and coauthors.

During the study, the researchers found that RSVpreF elicited robust immune responses after initial vaccination, significantly increasing RSV-A and RSV-B neutralizing antibody titers. Geometric mean fold rises (GMFRs) for RSV-A from before to 1 month after initial vaccination were 13.3 to 18.3 for younger adults and 8.9 to 13.3 for older adults. Corresponding GMFRs for RSV-B were 16.0 to 20.4 and 10.8 to 15.51, respectively.

Twelve months after initial vaccination, antibody levels remained elevated compared to baseline, with GMFRs of 4.2 to 5.0 in younger adults and 2.6 to 3.6 in older adults for RSV-A. For RSV-B, the GMFRs were 4.1 to 4.5 and 2.8 to 4.1, respectively.

Revaccination with RSVpreF at the 12-month mark resulted in a rapid boost of antibody levels, although not as high as the initial vaccination response. GMFRs 1 month after revaccination vs levels before revaccination ranged from 1.4 to 2.3 for younger adults and 1.4 to 2.2 for older adults for RSV-A.

Interestingly, the antibody decay rate after revaccination was slower than after the initial vaccination. This observation suggests that the immune system may develop a more durable response following repeated exposure to the vaccine.

Safety profiles for both initial vaccination and revaccination were favorable. Local reactions, such as injection site pain, were generally mild and more common in younger participants. Systemic events, including headache, muscle pain, and fatigue, were also mostly mild to moderate. The incidence of adverse events was similar between initial vaccination and revaccination, with no vaccine-related serious adverse events reported.

“Both initial vaccination and revaccination after 12 months with RSVpreF (240 μg) elicited robust RSV-A and RSV-B neutralizing antibody responses among healthy 18- to 49-year-old and 65- to 85-year-old adults,” concluded the study authors.

Reference

Walsh EE, Falsey AR, Zareba AM, et al. Respiratory Syncytial Virus Prefusion F Vaccination: Antibody Persistence and Revaccination. J Infect Dis. 2024;230(4):e905-e916. doi:10.1093/infdis/jiae185