Amongst eligible pregnant women, 64.0% received the RSVpreF vaccine, and 70.1% of eligible neonates received nirsevimab, according to a new study that was published in JAMA Network Open, yesterday. The investigators write that this translates to more than 80% coverage against RSV during all but the first month of the study.1
“This study suggests that an RSV prevention strategy that included both prenatal vaccination and infant monoclonal antibody administration had high uptake and reassuring perinatal outcomes,” they write.1
The Study Specifics and Other Takeaways
This was a retrospective cohort study performed at 1 academic center among 647 pregnant individuals eligible for RSVpreF vaccination (32-36 weeks’ gestation—between October 15, 2023, and January 31, 2024—and infants eligible for nirsevimab (no prenatal RSVpreF vaccination >14 days before delivery).1
Factors for higher uptake for the RSVpreF vaccine included older maternal age, first time pregnancy, private insurance, ethnicity, and a history of previous vaccinations. Conversely, lower uptake was associated with race, having a non-English preference, and having multiple gestations.1
Nirsevimab was given to 183 of 261 eligible infants before hospital discharge. Additionally, there were some immunization gaps covered including 40.4% of infants whose mothers didn't receive the RSV vaccine or standard prenatal vaccines still got nirsevimab. And 34% of infants who missed their hepatitis B vaccination received nirsevimab.1
What You Need to Know
64% of eligible pregnant individuals received the RSVpreF vaccine, and 70.1% of eligible infants received nirsevimab.
Higher uptake for the RSVpreF included older maternal age, first time pregnancy, private insurance, ethnicity, and a history of previous vaccinations. Conversely, lower uptake was associated with having a non-English preference, race, and having multiple gestations.
The study highlighted the critical role of obstetric clinicians—78% of RSV vaccines were administered during prenatal visits, showing how onsite vaccination can boost uptake.
RSVpreF Vaccine and Nirsevimab
The bivalent RSV prefusion F (RSVpreF) vaccine from Pfizer was FDA approved in 2023.It is unadjuvanted and composed of 2 preF proteins selected to optimize protection against RSV A and B strains. The vaccine is administered to pregnant women between 32 and 36 weeks gestational age.3
Nirsevimab was also FDA approved in 2023, and Sanofi and AstraZeneca’s nirsevimab is indicated for the prevention of RSV lower respiratory tract disease LRTD in newborns and infants born during or entering their first RSV season, and for children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season. Nirsevimab is a single-dose long-acting monoclonal antibody provided directly to newborns and infants as a single dose.4
Invited commentary from Naima Joseph, MD, MPH, and Geeta Swamy, MD, discuss the significance of this study.
"A major strength of the study is the high prenatal vaccination coverage. The simultaneous introduction of multiple RSV immunization products, each aimed at different groups—pregnant people, older adults, and infants—with distinct eligibility criteria, payment mechanisms, and insufficient systems to maintain patient and clinician awareness regarding vaccine safety, efficacy, and availability, contributed to the overall low uptake last season,” Joseph and Swamy write. “However, the authors achieved vaccination of 64% of birthing parents, with 78% of vaccines administered during prenatal visits, underscoring the critical role that obstetric clinicians play in vaccine uptake by pregnant individuals and the importance of onsite referral mechanisms.”2
Joseph and Swamy point out there is still more information that needs to be understood. “Many unanswered questions remain, including the potential for infant protection through lactation, the safety and immunogenicity of simultaneous administration with other vaccines, and the ongoing need for surveillance of pregnancy outcomes in the context of current clinical practice patterns,” they write.2
References
1.Blauvelt CA, Zeme M, Natarajan A, et al. Respiratory Syncytial Virus Vaccine and Nirsevimab Uptake Among Pregnant People and Their Neonates. JAMA Netw Open. 2025;8(2):e2460735. doi:10.1001/jamanetworkopen.2024.60735
2. Joseph NT, Swamy GK. Maternal Immunization and the Implementation Gap—Strengthening Respiratory Syncytial Virus Infrastructure and Preparing for the Future. JAMA Netw Open. 2025;8(2):e2460743. doi:10.1001/jamanetworkopen.2024.60743
3. Bigica A. FDA Approves Pfizer's Maternal RSV Vaccine Abrysvo to Protect Infants. Contagion. August 21, 2023. Accessed February 20, 2025.
https://www.contagionlive.com/view/fda-approves-pfizer-maternal-rsv-vaccine-rsvpref-abrysvo-to-protect-infants
4. Parkinson J. FDA Approves Nirsevimab for RSV in Infants. Contagion. July 17, 2023. Accessed February 20, 2025.
