IDSA

IDWeek 2025: RSV shots for infants safe and effective, regardless of maternal vaccination status

October 27, 2025

New research presented at IDWeek 2025 confirms that RSV immunization in infants is safe and effective regardless of maternal vaccination status. The study followed 181 mother-infant pairs from eight U.S. sites, divided into four groups: maternal RSVpreF vaccination only; maternal vaccination plus infant nirsevimab immunization at birth; maternal vaccination plus infant immunization at three months; and infant immunization at birth only. All groups showed high RSV antibody levels at three months, and no adverse effects were reported in mothers or infants.

The findings address a key gap in prior research, which hadn’t evaluated post-birth immunization safety in infants whose mothers were vaccinated during pregnancy. RSV remains the leading cause of hospitalization in children under one year and a major driver of bronchiolitis and pneumonia. Current CDC guidance recommends maternal vaccination at 32 to 36 weeks and infant immunization for those under eight months without maternal protection. While most infants don’t require both interventions, this study provides reassurance for scenarios where dual protection is considered.

The study is ongoing, with researchers planning one-year follow-up to assess immune durability in mothers, infants, and breast milk. While early findings confirm the vaccine is safe and well tolerated in infants, long-term persistence of protective antibodies in both mothers and infants remains to be fully characterized.

Source:

(2025, October 19). Infectious Diseases Society of America. RSV Immunization in Infants Is Safe and Provides High Antibody Levels Regardless of Mother’s Vaccination Status [News release] https://www.idsociety.org/news--publications-new/articles/2025/rsv-immunization-in-infants-is-safe-and-provides-high-antibody-levels-regardless-of-mothers-vaccination-status/