The RSV pre-fusion F protein-based (RSVpreF) vaccine appears to be safe and effective for preventing RSV-associated lower respiratory tract illness (LRTI) in older adults, according to a study published in the New England Journal of Medicine. Edward Walsh, MD, and colleagues conducted a phase 3 trial in which adults aged 60 and older were randomly assigned to receive a single intramuscular injection of RSVpreF vaccine (N=17,215) or placebo (N=17,069). RSV-associated LRTI with at least two symptoms occurred in 11 participants in the vaccine group (1.19 cases per 1,000 person-years) and 33 participants in the placebo group (3.58 cases per 1,000 person-years), for a vaccine efficacy of 66.7%. Cases with at least three symptoms occurred in two participants receiving the vaccine and 14 receiving placebo (0.22 vs 1.52 cases per 1,000 person-years; vaccine efficacy, 85.7%). The incidence of local reactions was higher with the vaccine than with placebo (12% vs 7%), while the incidence of systemic events were similar, and similar rates of injection-related adverse events through 1 month were reported.