• Reduction observed in RSV-related hospitalisations in adults aged ≥60 years¹
• An observed reduction in major adverse cardiovascular events* in adults aged ≥60 years^ǂ2 during RSV-related hospitalisation
• Risk reduction observed against severe flare-ups of chronic obstructive pulmonary disease (COPD) and asthma^†2 during RSV-related hospitalisation

GSK plc (LSE/NYSE: GSK) today announced new effectiveness data for its adjuvanted recombinant respiratory syncytial virus (RSV) vaccine at RSVVW’26, the 9th Conference of the Respiratory Syncytial Virus Foundation (ReSViNET) in Rome, Italy. GSK is presenting 19 abstracts at the congress and supporting a further 3, reflecting GSK’s leadership in research and prevention of RSV.

Hospitalisation places a significant burden on patients and health systems, particularly in winter months.^3,4 A retrospective cohort study was undertaken in the US with the primary objective to assess the effectiveness of GSK’s RSV vaccine in helping to prevent RSV-related hospitalisation in adults aged ≥60 years. It included over 2.5 million people, of which 520,440 were vaccinated individuals who were exact matched 1:4 to 2,081,760 unvaccinated individuals.^1,2 The vaccinated group received vaccination between 1 August 2023 and 31 May 2024 and the study observed risk reductions in this season.

For GSK’s RSV vaccine, the study showed an association with 75.6% vaccine effectiveness (VE) against RSV-related hospitalisation at a median follow-up of 5.6 months (maximum 9.7 months) post-vaccination (unvaccinated group, n=1419/2,081,760; vaccinated group, n=95/520,440; 95% confidence interval: 69.8–80.2%).^1,5 

Further exploratory endpoints showed an association with 63.1% VE against major adverse cardiovascular events (MACE), including heart attack and stroke, during RSV-related hospitalisation among adults aged ≥60 years,^‡2,5 (unvaccinated group, n=212/699,177; vaccinated group, n=21/170,803; 95% confidence interval: 41.8–76.6%). They also showed an association with 74.4% and 61.6% VE against severe COPD and asthma flare-ups respectively during RSV-related hospitalisation among adults aged ≥60 years^†2,5 (COPD unvaccinated group, n=265/286,406; vaccinated group, n=20/76,209; 95% confidence interval: 59.3–83.9%. Asthma unvaccinated group, n=57/190,590; vaccinated group, n=7/53,636; 95% confidence interval: 9.1–83.7%).

In a separate nation-wide cohort study conducted in Denmark in COPD patients aged ≥60 years,^≠ it was observed that GSK’s RSV vaccine was associated with VE of 100% in preventing RSV-related hospitalisations (unvaccinated group, n=115/89,376; vaccinated group, n=0/7448; 95% confidence interval: 71.1–100%).⁶ 

Analyses from both the US and Denmark studies will be presented at RSVVW’26.

While observational research cannot demonstrate a causal association between RSV vaccination and reduced RSV-related risks, these findings add to a growing body of evidence of observed risk reductions in cardiovascular and respiratory underlying diseases. GSK’s RSV vaccine is indicated for the prevention of RSV-lower respiratory tract disease (LRTD).

Deepak L. Bhatt, MD, MPH, MBA, Director of Mount Sinai Fuster Heart Hospital and the Dr. Valentin Fuster Professor of Cardiovascular Medicine at the Icahn School of Medicine at Mount Sinai in New York, said: “In the real-world data being presented at RSVVW’26, it is observed that RSV vaccination could help reduce the risk of certain serious RSV-related outcomes, potentially including major adverse cardiovascular events such as heart attack and stroke, as well as severe flare-ups of COPD and asthma. These new data are a significant step in our understanding of how to help prevent such RSV-related health outcomes. I look forward to more data investigating this association further.”

Christian Felter, GSK Global Medical Lead, RSV, said: “These data underscore the value of our RSV vaccine in its observed association with helping to prevent RSV-related hospitalisation and reducing the risk of acute events of certain chronic conditions associated with this potentially serious disease. We are proud of our contribution at the forefront of generating innovative research in RSV to inform the clinical community and improve outcomes for patients.”

* Major adverse cardiovascular events (MACE) were defined in this analysis as: myocardial infarction, ischemic stroke, heart failure-related hospitalisation, or unstable angina-related hospitalisation.
ǂ among US adults aged 60 years and older with existing cardiovascular disease (CVD)
† among US adults aged 60 years and older with existing chronic obstructive pulmonary disease (COPD) and asthma, respectively
≈ Dr. Bhatt is a paid consultant to GSK, who sponsored this study, and a co-author of a related study (#482 below).
≠ among Danish adults aged 60 years and older with existing chronic obstructive pulmonary disease (COPD)

The two abstracts presented report findings from a retrospective cohort study conducted using US administrative claims data from the Optum Research Database (ORD; August 2022–May 2024).^1,2 The first abstract evaluates VE against RSV-related hospitalisation (defined by International Classification of Diseases, Tenth Revision, Clinical Modification diagnosis codes for RSV).² The second abstract estimates VE of GSK’s RSV vaccine against MACE, and against severe flare-ups of COPD and asthma.¹ A total of 520,440 vaccinated and 2,081,760 unvaccinated individuals were included in the overall study.^1,2 The analyses included adults aged ≥60 years identified between August 2023–May 2024.^1,2

Respiratory syncytial virus vaccine (recombinant, adjuvanted) contains recombinant RSV glycoprotein F stabilised in the prefusion conformation (RSVPreF3). This antigen is combined with GSK’s proprietary AS01E adjuvant before administration. 

The use of this vaccine should be in accordance with official recommendations. As with any vaccine, a protective immune response may not be elicited in all vaccinees.

The vaccine has been approved for the prevention of RSV-lower respiratory tract disease (LRTD) in individuals 60 years of age and older in more than 65 countries. In addition, it is approved for use in individuals aged 50-59 who are at increased risk due to certain underlying medical conditions in more than 55 countries, including the US and Japan. In the European Economic Area, it is approved for use in adults aged 18 years and older. Please refer to the Product Information (PI) for important dosage, administration, and safety information in Europe at this link: http://www.ema.europa.eu/medicines/human//EPAR/arexvy and in the US at this link: https://gskpro.com/content/dam/global/hcpportal/en_US/Prescribing_Information/Arexvy/pdf/AREXVY.PDF 

The GSK proprietary AS01 adjuvant system contains STIMULON QS-21 adjuvant licensed from Antigenics LLC, a wholly owned subsidiary of Agenus Inc. STIMULON is a trademark of SaponiQx Inc., a subsidiary of Agenus.

RSV is a common contagious virus affecting the lungs and breathing passages and impacts an estimated 64 million people of all ages globally every year.⁷ Adults can be at increased risk for severe RSV disease due to certain comorbidities including COPD, asthma, and chronic heart failure, immune compromised status, or advanced age.⁸ In the US, it is estimated that there are between 6,000 and 10,000 RSV-related deaths annually in older adults and between 110,000 and 180,000 hospitalisations in people aged 50 and over.^9,10 RSV can exacerbate certain medical conditions, and lead to severe illness resulting in hospitalisation and even death.^8,11,12 Compared to children, adults hospitalised for RSV are at a higher risk of severe complications, require more costly treatments, have a higher fatality rate, and the true number of RSV-related cases is likely underestimated due to lack of routine testing.^13,14,15,16

GSK is a global biopharma company with a purpose to unite science, technology, and talent to get ahead of disease together. Find out more at www.gsk.com.

GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described in the “Risk Factors” section in GSK’s Annual Report on Form 20-F for 2024, and GSK’s Q4 Results for 2025.

1. Singer D, et al. Adjuvanted RSVPreF3 vaccine effectiveness against RSV-related hospitalization among US adults aged 60 years and older. Abstract presented at Respiratory Syncytial Virus network (ReSViNET) 2026 Congress; 17–20 February, Rome, Italy
2. Singer D, et al. Effectiveness of adjuvanted RSVPreF3 vaccine in preventing major adverse cardiovascular events, severe asthma exacerbations, and severe COPD exacerbations among US adults aged 60 years and older. Abstract presented at Respiratory Syncytial Virus network (ReSViNET) 2026 Congress; 17–20 February, Rome, Italy
3. European Centre for Disease Prevention and Control. Acute respiratory infections in the EU/EEA: epidemiological update and current public health recommendations – winter 2024/2025. Available at: https://www.ecdc.europa.eu/en/news-events/acute-respiratory-infections-eueea-epidemiological-update-and-current-public-health-0. Last accessed: February 2026
4. Savić, M., Penders, Y., Shi, T., Campbell, H., & Nair, H. (2023). Respiratory syncytial virus disease burden in adults aged 60 years and older in high-income countries: A systematic literature review and meta-analysis. Influenza and Other Respiratory Viruses, 17(1), e13031. https://doi.org/10.1111/irv.13031
5. GSK. Data on file, 2024N560279.
6. Fonseca M, et al. Real-World Evidence of the Adjuvanted-RSVPreF3 Vaccine’s Uptake and Effectiveness among Chronic Obstructive Pulmonary Disease Patients in Denmark: A Nationwide Cohort Study. Abstract presented at Respiratory Syncytial Virus network (ReSViNET) 2026 Congress; 17–20 February, Rome, Italy
7. National Institute of Allergy and Infectious Diseases, Respiratory Syncytial Virus (RSV). Available at: https://www.niaid.nih.gov/diseases-conditions/respiratory-syncytial-virus-rsv. Last accessed: February 2026
8. Atamna A, et al. Morbidity and mortality of respiratory syncytial virus infection in hospitalized adults: Comparison with seasonal influenza. Int J Infect Dis. 2021 Feb:103:489-493. doi: 10.1016/j.ijid.2020.11.185
9. Kim T & Choi SH. Epidemiology and Disease Burden of Respiratory Syncytial Virus Infection in Adults. Infect Chemother. 2024 Mar;56(1):1-12. doi: 10.3947/ic.2024.0011. Epub 2024 Mar 12. PMID: 38527779; PMCID: PMC10990889.
10. Centers for Disease Control and Prevention. Respiratory Syncytial Virus Infection (RSV). Available at: https://www.cdc.gov/rsv/adults/index.html. Last accessed: February 2026
11. Osei-Yeboah R, et al. Estimation of the Number of Respiratory Syncytial Virus–Associated Hospitalizations in Adults in the European Union. J Infect Dis 2023 May 29;228(11):1539–1548. doi: 10.1093/infdis/jiad189
12. Falsey, AR et al. Respiratory syncytial virus infection in elderly and high-risk adults, in New Engl J Med 2005; 352:1749-59. doi: 10.1056/NEJMoa043951
13. Niekler, P, et al. Hospitalizations due to respiratory syncytial virus (RSV) infections in Germany: a nationwide clinical and direct cost data analysis (2010-2019). Infection. 2024 Oct;52(5):1715-1724. doi: 10.1007/s15010-023-02122-8
14. Günen H, et al. Key Challenges to Understanding the Burden of Respiratory Syncytial Virus in Older Adults in Southeast Asia, the Middle East, and North Africa: An Expert Perspective. Adv Ther. 2024 Nov;41(11):4312-4334. https://doi.org/10.1007/s12325-024-02954-2
15. Alfano, F., Bigoni, T., Caggiano, F.P. et al. Respiratory Syncytial Virus Infection in Older Adults: An Update. Drugs Aging 41, 487–505 (2024). https://doi.org/10.1007/s40266-024-01118-9
16. Grace, M., Colosia, A., Wolowacz, S., Panozzo, C., & Ghaswalla, P. (2023). Economic burden of respiratory syncytial virus infection in adults: a systematic literature review. Journal of Medical Economics, 26(1), 742–759. https://doi.org/10.1080/13696998.2023.2213125