Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease in infants, with the highest burden in those under 6 months of age. Global RSV epidemics occur seasonally and nearly all children are infected within the age of 2 years, resulting in significant hospitalizations, morbidity, and healthcare costs. Enflonsia™ (clesrovimab-cfor), recently approved by the U.S. Food and Drug Administration, is a long-acting recombinant monoclonal antibody targeting the prefusion F protein of RSV, preventing viral entry and replication. A single intramuscular dose provides protection across the RSV season, eliminating the need for monthly injections. Clinical trials indicate that clesrovimab reduces RSV-related hospitalizations by up to 76% and medically attended RSV disease by over 70%, with a safety profile comparable to existing antibodies like palivizumab and nirsevimab. Common adverse events include mild injection-site reactions and rare hypersensitivity. While its high cost and cold-chain requirements may limit accessibility in low- and middle-income countries, the single-dose, season-long protection offers logistical advantages and potential cost-effectiveness in high-burden settings. Enflonsia represents a significant advance in infant RSV prophylaxis, with implications for global health strategies, integration into immunization programs, and equitable access to reduce RSV morbidity worldwide.
Chandani et al. (Tue,) studied this question.