Adjuvanted RSVPreF3 vaccine impact over 3 RSV seasons in older adults with comorbidities

Background We explored the efficacy of AS01 E -adjuvanted respiratory syncytial virus prefusion F protein-based vaccine (adjuvanted RSVPreF3) in subpopulations of participants with underlying medical conditions in the multi-country, phase 3 AReSVi-006 trial (conducted May/2021-May/2024). Methods Medically stable ≥60-year-olds were 1:1-randomised to receive one adjuvanted RSVPreF3 or placebo dose pre-RSV season 1. In exploratory post-hoc analyses in subgroups of participants with underlying conditions (including COPD, asthma, diabetes, obesity [BMI≥30 kg·m −2 ]), we evaluated efficacy of one vaccine dose against RSV-related lower respiratory tract disease (RSV-LRTD), acute respiratory illness (RSV-ARI), and RSV-ARI-related complications ( e.g. , pneumonia, COPD/asthma exacerbation, cardiovascular events). We also evaluated (post-hoc) RSV-ARI-related systemic corticosteroid and antibiotics use in participants with COPD or asthma. Results The efficacy analyses comprised 12 468 vaccine and 12 498 placebo recipients. Efficacy against RSV-LRTD over three RSV seasons was similar among participants with COPD (75.1%, 95% CI: 40.2–91.4), asthma (65.8%, 31.0–84.7), diabetes (69.8%, 37.5–87.1), and obesity (74.1%, 56.4–85.5) as in the overall study population (62.9%, 97.5% CI: 46.7–74.8). Efficacy was also observed against RSV-ARI in these subgroups. Efficacy against RSV-ARI-related complications was 74.4% (95% CI: 11.2–95.2) in participants with COPD and 60.8% (−9.9–88.7) in those with asthma. Among participants with COPD, 15.4% (1.9–45.4) of RSV-ARI episodes in vaccine versus 22.4% (12.5–35.3) in placebo recipients were treated with systemic corticosteroids, and 46.2% (19.2–74.9) versus 56.9% (43.2–69.8) with antibiotics. Conclusions Post-hoc analyses of the AReSVi-006 trial suggest that adjuvanted RSVPreF3 may help prevent RSV-ARI, RSV-LRTD, and RSV-related complications in medically stable older adults with underlying medical conditions like COPD and asthma.