A new study indicates that babies whose mothers received vaccination against the Respiratory Syncytial Virus (RSV) during pregnancy, or who were immunized with Nirsevimabe after birth, they had significantly lower rates of infection and lower use of health services.
The also showed a reduction in the incidence of serious complications among immunized babies. The results were presented at the 2026 Pediatric Academic Societies (PAS) Meeting, between April 24 and 27, in Boston.
RSV is a leading cause of respiratory infections and hospitalizations in babies under six months of age in the United States.
In 2023, the FDA approved two preventive strategies: Pfizer, applied between the 32nd and 36th week of pregnancy, and , from Sanofi, a long-lasting monoclonal antibody administered to newborns.
Despite approval, data on effectiveness in real conditions is still limited, especially in more vulnerable populations.
The study was conducted in Nova Yorkduring the period when the state faced a “triple epidemic” of RSV, influenza and COVID-19 in October 2023.
The researchers analyzed hospitalizations, the need for respiratory support and clinical outcomes over 180 days after infection, also considering the circulation of other respiratory viruses.
“The burden of RSV disease in this population of infants is enormous, resulting in approximately half a million emergency room visits and more than 100,000 hospital admissions per year,” said Uday Patil, vice president of Pediatrics at NYC Health and senior author of the study.
“Our study investigated the impact of these immunizations during the first season after their availability on preventing morbidities related to RSV infection in infants less than 6 months of age in one of the most diverse and medically underserved neighborhoods in Queens, New York City, served by Elmhurst Hospital.”
According to the researcher, there was high adherence to preventive strategies. “We observed high adherence (>65%) to maternal RSV vaccine (Abrysvo) among our pregnant patients and to childhood immunization (Beyfortus) among newborns (>90%).
This indicates strong patient confidence in the healthcare system within our vulnerable population,” he said. Patil also highlighted the direct impact on clinical outcomes.
“RSV infection rates, hospitalizations, and disease severity decreased significantly among babies in our study, demonstrating the high efficacy of both immunizations. Our findings provide pragmatic results, emphasizing that these new developments are transformative and confirming the adage that ‘prevention is better than cure!’”.
