Ferguson, MurdoSchwarz, Tino FNúñez, Sebastián ARodriguez-Garcia, JuanMital, MarekZala, CarlosSchmitt, BernhardToursarkissian, NicoleMazarro, Dolores OchoaGroßkopf, JosefVoors-Pette, ChristineMehta, HemaliniHailemariam, Hiwot Amarede Heusch, MagaliSalaun, BrunoDamaso, SilviaDavid, Marie-PierreDescamps, DominiqueHill, JudithVandermeulen, CorinneHulstrøm, Veronica2024-09-042024-09-042024-08-05Ferguson M, Schwarz TF, Núñez SA, Rodríguez-García J, Mital M, Zala C, et al. Noninferior Immunogenicity and Consistent Safety of Respiratory Syncytial Virus Prefusion F Protein Vaccine in Adults 50-59 Years Compared to ≥60 Years of Age. Clin Infect Dis. 2024 Aug 5.https://hdl.handle.net/20.500.13003/20943The adjuvanted respiratory syncytial virus (RSV) prefusion F protein-based vaccine (RSVPreF3 OA) is approved in adults aged ≥60 years. We evaluated RSVPreF3 OA immunogenicity and safety in adults aged 50-59 years without or with increased risk for RSV disease due to specific chronic medical conditions. This observer-blind, phase 3, noninferiority trial included adults aged 50-59 years, stratified into 2 subcohorts: those with and those without predefined, stable, chronic medical conditions leading to an increased risk for RSV disease. Participants in both subcohorts were randomized 2:1 to receive RSVPreF3 OA or placebo. A control group of adults aged ≥60 years received RSVPreF3 OA. Primary outcomes were RSV-A and RSV-B neutralization titers (geometric mean titer ratios and sero-response rate differences) 1 month post-vaccination in 50-59-year-olds versus ≥60-year-olds. Cell-mediated immunity and safety were also assessed. The exposed population included 1152 participants aged 50-59 years and 381 participants aged ≥60 years. RSVPreF3 OA was immunologically noninferior in 50-59-year-olds versus ≥60-year-olds; noninferiority criteria were met for RSV-A and RSV-B neutralization titers in those with and those without increased risk for RSV disease. Frequencies of RSVPreF3-specific polyfunctional CD4+ T cells increased substantially from pre- to 1 month post-vaccination. Most solicited adverse events had mild-to-moderate intensity and were transient. Unsolicited and serious adverse event rates were similar in all groups. RSVPreF3 OA was immunologically noninferior in 50-59-year-olds compared to ≥60-year-olds, in whom efficacy was previously demonstrated. The safety profile in 50-59-year-olds was consistent with that in ≥60-year-olds. ClinicalTrials.gov: NCT05590403.engAtribución 4.0 Internacionalhttp://creativecommons.org/licenses/by/4.0/research article10.1093/cid/ciae3641537-659139099093L644931519001283243800001open access