Aims: RSV-associated acute respiratory infections (ARI), particularly lower respiratory tract diseases (LRTD), present a significant disease burden in older adults. Currently, there are no approved vaccines against RSV. We present results from an ongoing, phase 3, observer-blind, placebo-controlled, multi-country study that enrolled adults ≥ 60 YOA from the northern and southern hemispheres designed to demonstrate the vaccine efficacy (VE) of the AS01E-adjuvanted RSVPreF3 OA in adults ≥ 60 YOA.
Methods: A total of 26,664 participants were enrolled, of whom 24,966 (RSVPreF3 OA: 12,467; placebo: 12,499) were included in the exposed set and 24,960 (RSVPreF3 OA: 12,466; placebo: 12,494) in the efficacy analysis. The mean age was 69.5 (±6.5) years and 51.7% were women.
Results: Over a median follow-up of 6.7 months (maximum 10.1 months), 47 RSV-confirmed LRTD episodes were reported (RSVPreF3 OA: 7; placebo: 40), resulting in a VE of 82.6% (96.95% CI: 57.9–94.1), thus the primary objective was met. Consistently high VE across the clinical spectrum of RSV disease, from RSV-confirmed ARI (71.7% [95% CI: 56.2–82.3]) to severe RSV-confirmed LRTD (94.1% [95% CI: 62.4–99.9]) was observed. High VE was seen in different age groups and regardless of RSV subtype, baseline comorbidity or pre-frail status. Cumulative incidence curves for RSV-confirmed LRTD and RSV-confirmed ARI showed persistent efficacy throughout the follow-up.
Conclusions: A single RSVPreF3 OA dose is highly efficacious against RSV-confirmed LRTD and RSV-confirmed ARI in adults ≥ 60 YOA, regardless of RSV disease severity, RSV subtype, baseline comorbidity and pre-frail status.
Funding: GlaxoSmithKline Biologicals SA (10.1093/ofid/ofac492.1868).
Acknowledgements: Modis platform for the original abstract submitted at IDWeek and Business & Decision Life Sciences for this ENCORE abstract.
ENCORE of IDWeek 2022.