Reviewed by Kavita Warrier MD, University of Michigan
Both maternal RSV vaccination and infant nirsevimab administration are approved for the prevention of RSV lower respiratory tract infection in young infants. This study aims to evaluate the safety and immunogenicity of maternal RSV vaccination, infant nirsevimab administration, or both sequentially in mothers and infants. Infants were randomized to one of four groups: maternal RSV vaccination alone (1A); maternal RSV vaccination + infant nirsevimab at birth (1B); maternal RSV vaccination + infant nirsevimab at 3 months (1C); or infant nirsevimab at birth.
181 mothers were enrolled at the time point of this analysis; 180 mothers and 179 infants were included in the analysis. The groups overall did not significantly differ. There were no maternal serious adverse events; infants had mild to moderate events balanced across groups, which included local reactions, sleepiness or fatigue, or irritability/crying.
In terms of immunogenicity, mothers had significant increases in titers for RSV-A and RSV-B antibodies after vaccination, which remained present after 3 months. Infants born to mothers who were vaccinated had elevated titers at birth; those not given nirsevimab at birth had decreased titers by 3 months of age, though still elevated. Infants born to mothers who were not vaccinated but received nirsevimab had low titers at birth, that rose significantly by day of life 43, and which remained present through 3 months of age. Infants born to mothers who received RSV vaccine and who received nirsevimab at birth had high titers at birth, which persisted through 3 months of age.
Overall, the study confirms the safety of both methods of infant protection against RSV. Both methods also show durable antibodies in infants, with only subtle differences in longevity and kinetics.
Reference:
Christina A. Rostad, C. Mary Healy, Jennifer L. Nayak, Lalitha Parameswaran, C. Buddy Creech, Judith M. Martin, Rebecca C. Brady, Kimberly Jones-Beatty, Martina Badell, Catherine Eppes, Michael Quinn, Mark Mulligan, Stephanie L. Rolsma, Anne-Marie Rick, Braxton Forde, Vasanthi Avadhanula, Pedro A. Piedra, Kalyani Telu, Pratap S. Kunwar, Jinjian Mu, Fei Gao, Marcela F. Pasetti, Britta Flach, Christine M. Posavad, Joy Miedema, Jeanna M. Piper, Sonnie Kim, Tatiana Beresnev, Cristina Cardemil, James D. Campbell; Maternal RSV Vaccination, Infant Nirsevimab, or Both: Interim Analysis of a Randomized Trial. Pediatrics June 2026; 157 (6): e2025075223. 10.1542/peds.2025-075223