RSVpreF Vaccine’s Effects on Severe Outcomes of RSV Infection

The clinical trials leading to licensure of the respiratory syncytial virus (RSV) vaccines were not designed to assess the vaccines’ efficacy against the severe outcome (RSV-associated hospitalization) or the nonspecific associated outcomes (all-cause cardiorespiratory hospitalization or cardiovascular hospitalization). Accordingly, investigators in Denmark performed a partially industry-funded randomized pragmatic trial in which some 65,600 participants received RSV vaccine and 65,600 did not (mean age, 69; 42% with at least one chronic disease). Outcomes were assessed using national healthcare databases during the 2024–2025 respiratory viral season. Pfizer’s RSVpreF vaccine was administered.