Studies Find Infant RSV Immunizations Remain Effective, No Evidence of Widespread Viral Mutation
Two new studies indicate that immunizations designed to prevent respiratory syncytial virus (RSV) infections in infants continue to be effective three years after their approval. One study, published in JAMA Network Open by Canadian researchers, found that nirsevimab, a lab-grown antibody, significantly reduced RSV-related emergency department visits by 77%, hospitalizations by 79%, and intensive care unit admissions by 97%. Notably, about 97% of infants testing positive for RSV in this analysis were otherwise healthy and had no underlying conditions. A separate study published in Nature, conducted by researchers from Seattle’s Fred Hutchinson Cancer Center and the University of Washington, examined 60,000 genetic sequences of circulating RSV viruses globally. This research found that resistance mutations to nirsevimab and another monoclonal antibody, clesrovimab, were rare, occurring in less than 1% of sequences.
