What 2 Seasons of Arexvy Data Reveal About RSV-Related Risk Reduction

Real-world data spanning 2 respiratory syncytial virus (RSV) seasons show adjuvanted RSVPreF3 vaccination (Arexvy) reduces the risk of RSV-related major adverse cardiovascular events (MACE), severe chronic obstructive pulmonary disease (COPD) exacerbations, and severe asthma exacerbations in adults 60 years and older.^1,2

Ann Falsey, MD, professor of medicine at the University of Rochester School of Medicine, whose research focuses on clinical and translational studies of respiratory viral infections in adults, discussed the findings with HCPLive during the 2026 European Respiratory Society (ERS) Congress.¹

Study Design: Two-Season Claims Data From the ERS Congress Late-Breaker

The 2-season analysis was presented as a late-breaking poster at the ERS Congress 2026 in Barcelona, Spain, extending 1-season findings GSK presented in February 2026 at RSVVW'26. The retrospective study used Optum Research Database claims data (August 2022-May 2025), comparing 662,982 vaccinated adults with 2,651,928 unvaccinated adults, matched and propensity-weighted for baseline balance.

"They all dropped a little from season one to cumulative over season two, but to my way of thinking, they're in the same ballpark. You have to look at the confidence intervals, not just the point prevalence. These severe outcomes of major cardiovascular events, COPD exacerbations, and asthma exacerbations are, in my mind, all in the same range," Falsey said.

Vaccine Effectiveness Holds Steady Across Outcomes in Season Two

The 2-season analysis found VE of 58.5% against RSV-related MACE (95% CI, 46.0-68.1%), 57.6% against severe COPD exacerbations (95% CI, 46.1-66.7%), and 57.3% against severe asthma exacerbations (95% CI, 22.3-76.6%). These figures converge more tightly across outcomes than the season 1 data GSK presented at RSVVW'26, when VE measured 63.1%, 74.4%, and 61.6% for the same three endpoints. Falsey said similar protection against COPD and asthma exacerbations fits with RSV's tendency to trigger airway hyperreactivity regardless of the underlying obstructive disease.

Interpreting Real-World Claims Data: Bias and Limitations

Falsey noted comparisons of vaccinated and unvaccinated populations carry inherent risk of healthy user bias, since people who seek vaccination often engage in other health-protective behavior. Investigators addressed this using propensity score matching to balance the 2 cohorts, though Falsey cautioned some unmeasured bias can persist even with careful matching.

Weighing Industry-Funded Real-World Evidence Against Randomized Trial Data

The study was funded by GSK, with most coauthors employed by GSK or Optum. Falsey, an independent academic investigator, reviewed the data and interpretation. She said real-world evidence complements randomized trial data by capturing populations, such as immunocompromised and frail adults, generally excluded from clinical trials, along with infrequent endpoints such as hospitalization.

When Might a Second Dose of Arexvy Make Sense?

Falsey called revaccination timing purely conjectural but estimated a second dose might make sense around 3 to 4 years post-vaccination, depending on the threshold of protection against serious outcomes clinicians and patients find acceptable. The poster's authors noted the 2-season results may help inform future recommendations on revaccination timing.

Editor’s note: Falsey reports institutional research support from AstraZeneca, BioFire Diagnostics, Janssen, Merck, Moderna, Pfizer, and Sanofi Pasteur, and personal/advisory fees from CyanVac, GSK, and Vax Co. This transcript has been edited for grammar and clarity using artificial intelligence tools.

References

1. Singer D, Horn EK, Falsey AR, et al. Adjuvanted RSVPreF3 vaccine effectiveness against cardiovascular events and disease exacerbations (2023-2025). Poster presented at the European Respiratory Society (ERS) Congress; September 6, 2026. Barcelona, Spain.

2. GSK. GSK’s AREXVY Associated With Reductions in Certain RSV-Related Risks Including Heart Attack, Stroke, and Severe Flare-Ups of COPD and Asthma, Real World Study Shows. BusinessWire. February 18, 2026. Accessed September 11, 2026. https://www.businesswire.com/news/home/20260217706893/en/GSKs-AREXVY-Associated-With-Reductions-in-Certain-RSV-Related-Risks-Including-Heart-Attack-Stroke-and-Severe-Flare-Ups-of-COPD-and-Asthma-Real-World-Study-Shows.