A multinational analysis reported that reductions in infant bronchiolitis after nirsevimab introduction varied widely across Europe and closely tracked regional immunization coverage, highlighting how real-world outcomes depend on baseline uptake rather than product performance alone. The study also reinforces the practical need to pair new monoclonal antibody programs with consistent implementation metrics—coverage, timing, and local adherence—to prevent underestimation of impact in under-covered regions. For payers and health systems, the findings suggest that rollout strategies should be evaluated alongside existing respiratory prophylaxis programs, because coverage gaps can dilute measured effectiveness at the population level.