RSV Prefusion F Vaccine Prevents RSV Illness in Older Adults

The bivalent respiratory syncytial virus (RSV) prefusion F (RSVpreF) vaccine prevented RSV-associated lower respiratory tract illness and RSV-associated acute respiratory illness in older adults without obvious safety concerns, according to study results published in The New England Journal of Medicine.

The ongoing, phase 3 RENOIR clinical trial randomly assigned adults 60 years of age and older to a single intramuscular injection of either RSVpreF vaccine at a dose of 120 μg or placebo. The study reported results from an interim analysis that included 17,215 participants who received RSVpreF vaccine and 17,069 participants who received placebo.

According to the findings, RSV-associated lower respiratory tract illness with at least two signs or symptoms occurred in 11 older adults who received the vaccine and 33 older adults who received placebo, for a vaccine efficacy of 66.7%. Meanwhile, RSV-associated lower respiratory tract illness with at least three signs or symptoms occurred in two older adults who received the vaccine and 14 who received placebo. The vaccine efficacy for preventing RSV-associated lower respiratory tract illness with at least three signs or symptoms was 85.7%.

RSV-associated acute respiratory illness occurred in 22 older adults in the vaccine group and 58 in the placebo group, for a vaccine efficacy of 62.1%, the study found.

The incidence of local reactions was 12% with the vaccine and 7% with placebo, researchers reported. The incidence of systemic events was 27% with the vaccine and 26% with placebo. 

“Severe or life-threatening adverse events were reported in 0.5% of vaccine recipients and 0.4% of placebo recipients,” wrote corresponding Alejandra Gurtman, MD, of Pfizer Vaccine Research and Development, Pearl River, New York, and study coauthors. “Serious adverse events were reported in 2.3% of participants in each group through the data-cutoff date.”

Reference: 
Walsh EE, Pérez Marc G, Zareba AM, et al. Efficacy and safety of a bivalent RSV prefusion F vaccine in older adults. N Engl J Med. 2023;388(16):1465-1477. doi:10.1056/NEJMoa2213836