Real-World Data Show GSK's RSV Vaccine Reduces Hospitalizations by 75.6% in Older Adults

GSK has unveiled new real-world effectiveness data for Arexvy, its adjuvanted respiratory syncytial virus (RSV) vaccine, at RSVVW'26, the 9th Conference of the Respiratory Syncytial Virus Foundation (ReSViNET), held in Rome. The company is presenting 19 abstracts at the congress and supporting an additional three, underscoring its expanding role in RSV research and prevention.

The centerpiece of GSK's presentation is a large U.S. retrospective cohort study involving more than 2.5 million adults aged 60 years and older. The analysis compared 520,440 vaccinated individuals with more than 2.08 million unvaccinated individuals who were matched at a 1:4 ratio. Participants in the vaccinated group received Arexvy between August 2023 and May 2024 and were followed for a median of 5.6 months.

Results showed that vaccination with Arexvy was associated with a 75.6% vaccine effectiveness (VE) against RSV-related hospitalization, with a 95% confidence interval of 69.8% to 80.2%. These findings suggest meaningful protection against severe RSV outcomes during the first season following immunization.

Exploratory analyses from the same study pointed to potential benefits beyond hospitalization prevention. Arexvy was associated with a 63.1% reduction in major adverse cardiovascular events (MACE), including heart attack and stroke, occurring during RSV-related hospitalizations. Additional analyses showed VE of 74.4% against severe chronic obstructive pulmonary disease (COPD) exacerbations and 61.6% against severe asthma flare-ups among vaccinated adults.

Complementing the US data, a separate nationwide cohort study in Denmark evaluated adults aged 60 years and older with COPD. In that analysis, AREXVY was associated with 100% effectiveness in preventing RSV-related hospitalization, with no hospitalizations observed among vaccinated individuals during the study period.

Arexvy is approved for the prevention of RSV-related lower respiratory tract disease (LRTD) in adults aged 60 years and older, as well as adults aged 50 to 59 years who are at increased risk. RSV remains a significant cause of hospitalization among older adults, particularly during winter respiratory virus seasons, placing strain on both patients and healthcare systems.

In May 2023, Arexvy received FDA approval as the first RSV vaccine targeting older adults, featuring recombinant protein technology that strengthens immune response against the RSV fusion protein.

Separate clinical guideline research published in the Annals of Internal Medicine analyzed the efficacy, comparative effectiveness, and harm of RSV vaccines in nonpregnant adults who are not immunocompromised in a review involving seven randomized controlled trials (RCTs) and one nonrandomized study. The researchers found that RSV protein subunit vaccines probably reduce RSV-related hospitalization (vaccine efficacy, 83.3%) and severe RSV illness (vaccine efficacy, 94.1%) in older adults (60 years and older), but have no effect on all-cause mortality risk. In terms of serious adverse events, the investigators note that they probably do not differ from placebo or no vaccination.

According to practice points developed by the American College of Physicians, adults aged 75 years or older should receive an RSV protein subunit vaccine. Receipt of an RSV protein subunit vaccine can be considered among adults aged 60 to 74 years who have an increased risk for severe RSV.

The respiratory syncytial virus (RSV) vaccine market is experiencing robust growth, driven by several factors. The market size is projected to expand from $1.37 billion in 2025 to $1.95 billion by 2030, with a compound annual growth rate (CAGR) of 7.5% during 2025-2026 and 7.2% during 2026-2030. This growth is primarily attributed to the increasing incidence of RSV-related hospitalizations, unmet medical needs in infant immunization, and heightened awareness of respiratory viral infections.