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Efficacy and Safety of a Bivalent RSV Prefusion F Vaccine in Older Adults
Edward E Walsh1, Gonzalo Pérez Marc1, Agnieszka M Zareba1
1From the University of Rochester Medical Center, Rochester (E.E.W., A.R.F.), and Vaccine Research and Development (E.D., G.C.V., M.I., D.E., T.M., R.N.S., K.S., D.C., K.K., K.U.J., K.A.S., A.G., W.C.G.) and Worldwide Research, Development, and Medical (A.S.A.), Pfizer, Pearl River - both in New York; iTrials-Hospital Militar Central (G.P.M.), Fundación INFANT (F.P.P.), and Fundación Respirar Clinical Research Unit (P.A.D.), Buenos Aires, and Clinica Mayo de Urgencias Médicas Cruz Blanca, San Miguel de Tucumán (C.L.) - all in Argentina; Vaccine Research and Development, Pfizer, Collegeville, PA (A.M.Z., Q.J.); Vaccine Research and Development, Pfizer, Hurley, United Kingdom (M.P.); Vaccine Research and Development, Pfizer, Raleigh, NC (K.I.); Faculty of Medicine and Health Technology, Tampere University, and Finnish Vaccine Research - both in Tampere, Finland (M.R.); Fukuwa Clinic, Tokyo (Y.F.); Netcare Lakeview Hospital, Benoni, South Africa (N.H.); the Departments of Pediatrics and Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, and Respiratory Syncytial Virus Network Foundation, Zeist - both in the Netherlands (L.J.B.); Indago Research and Health Center, Hialeah, FL (J.C.); Worldwide Safety, Pfizer, Milan (M.-M.L.); and Vaccine Research and Development, Pfizer Pharma, Berlin (B.S.-T.).
Background:
Respiratory syncytial virus (RSV) infection causes considerable illness in older adults. The efficacy and safety of an investigational bivalent RSV prefusion F protein-based (RSVpreF) vaccine in this population are unknown.
Methods:
In this ongoing, phase 3 trial, we randomly assigned, in a 1:1 ratio, adults (≥60 years of age) to receive a single intramuscular injection of RSVpreF vaccine at a dose of 120 μg (RSV subgroups A and B, 60 μg each) or placebo. The two primary end points were vaccine efficacy against seasonal RSV-associated lower respiratory tract illness with at least two or at least three signs or symptoms. The secondary end point was vaccine efficacy against RSV-associated acute respiratory illness.
Results:
At the interim analysis (data-cutoff date, July 14, 2022), 34,284 participants had received RSVpreF vaccine (17,215 participants) or placebo (17,069 participants). RSV-associated lower respiratory tract illness with at least two signs or symptoms occurred in 11 participants in the vaccine group (1.19 cases per 1000 person-years of observation) and 33 participants in the placebo group (3.58 cases per 1000 person-years of observation) (vaccine efficacy, 66.7%; 96.66% confidence interval [CI], 28.8 to 85.8); 2 cases (0.22 cases per 1000 person-years of observation) and 14 cases (1.52 cases per 1000 person-years of observation), respectively, occurred with at least three signs or symptoms (vaccine efficacy, 85.7%; 96.66% CI, 32.0 to 98.7). RSV-associated acute respiratory illness occurred in 22 participants in the vaccine group (2.38 cases per 1000 person-years of observation) and 58 participants in the placebo group (6.30 cases per 1000 person-years of observation) (vaccine efficacy, 62.1%; 95% CI, 37.1 to 77.9). The incidence of local reactions was higher with vaccine (12%) than with placebo (7%); the incidences of systemic events were similar (27% and 26%, respectively). Similar rates of adverse events through 1 month after injection were reported (vaccine, 9.0%; placebo, 8.5%), with 1.4% and 1.0%, respectively, considered by the investigators to be injection-related. Severe or life-threatening adverse events were reported in 0.5% of vaccine recipients and 0.4% of placebo recipients. Serious adverse events were reported in 2.3% of participants in each group through the data-cutoff date.
Conclusions:
RSVpreF vaccine prevented RSV-associated lower respiratory tract illness and RSV-associated acute respiratory illness in adults (≥60 years of age), without evident safety concerns. (Funded by Pfizer; RENOIR ClinicalTrials.gov number, NCT05035212; EudraCT number, 2021-003693-31.).
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