Maternal RSV vaccination linked to nearly 70% lower RSV hospitalization risk in infants

Clinical Takeaway: Maternal RSV vaccination offers clinicians an effective strategy to protect infants during the first months of life, when RSV hospitalization risk is highest and treatment options are limited. These real-world data may help inform discussions with pregnant patients who are considering RSV prevention for their newborns.

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among US infants, particularly during the first months of life. New real-world data suggest that maternal RSV vaccination provides substantial protection against severe RSV illness requiring hospitalization.

Maternal RSV vaccination was associated with 67.6% effectiveness against RSV-associated hospitalization for acute respiratory illness and 69.0% effectiveness against RSV-associated lower respiratory tract disease hospitalization among infants aged 90 days or younger. Protection appeared strongest during the first month of life, with an estimated 74.2% reduction in RSV-associated hospitalization among infants aged 30 days or younger.

The study included 274 infants aged 90 days or younger who were hospitalized with acute respiratory illness during the first two RSV seasons following implementation of maternal RSV vaccination in the United States. Investigators compared infants who tested positive for RSV with RSV-negative controls and excluded those who received nirsevimab or other RSV preventive agents.

Researchers will continue following participants through future RSV seasons to evaluate protection through 180 days of age and better define the durability of protection over time.

“We designed this study to focus on what matters most to families: whether their baby might end up in the hospital,” said Anne-Marie Rick, MD, PhD, assistant professor of Pediatrics and Clinical and Translational Science at the University of Pittsburgh School of Medicine. “The findings show a significant impact for families and for the health system, and it highlights how effective this intervention can be during the most vulnerable months of life.”

Source: Rick AM, et al. 2026 June 5. JAMA Netw Open. Maternal Respiratory Syncytial Virus Prefusion F Vaccination and Acute Respiratory Illness in Infants