29 Percent of Infants Immunized Against RSV in 2023 to 2024 Season

MONDAY, Aug. 25, 2025 (HealthDay News) — Overall, 29 percent of infants born during October 2023 to March 2024 were immunized against respiratory syncytial virus (RSV) during the 2023 to 2024 respiratory virus season, according to research published in the Aug. 21 issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.

Ellen O. Boundy, Sc.D., from the CDC in Atlanta, and colleagues estimated infant RSV immunization coverage by summing the total number of infants who received nirsevimab and the number of women of childbearing age who received an RSV vaccine in 33 U.S. states and the District of Columbia (DC), divided by the total number of live births.

The researchers estimated that 29 percent of infants born during October 2023 to March 2024 were immunized against RSV during the 2023 to 2024 respiratory virus season across 33 states and DC, including 19 and 10 percent through infant receipt of nirsevimab and maternal RSV vaccination, respectively. By state, infant RSV immunization coverage through nirsevimab or maternal vaccination ranged from an estimated 11 to 53 percent. Thirty-eight percent of infants who received nirsevimab received it within the first week of life.

“Additional efforts are needed to increase infant protection against severe RSV through maternal or infant immunization,” the authors write.

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