The Fight Against RSV Begins with Vaccination

Pregnant women with vaccination

Image credits: Unsplash

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among infants in the United States. To combat this, the CDC recommends vaccination for pregnant individuals and the administration of the RSV antibody nirsevimab to infants under 8 months. This study aimed to assess the maternal and infant RSV immunization coverage for the 2023–24 RSV season.

A survey conducted between March 26 and April 11, 2024, revealed that among 678 women at 32–36 weeks’ gestation, 32.6% had received an RSV vaccine during pregnancy. For 866 women with infants born from August 2023 to March 2024, 44.6% reported that their infant had received nirsevimab. Overall, 55.8% of infants were protected through maternal vaccination, nirsevimab, or both. A provider's recommendation significantly correlated with higher immunization rates, while a lack of such recommendations was the primary reason for not receiving immunization. Concerns regarding the long-term safety of nirsevimab were noted as the main hesitation among parents.

“Complexities in the RSV prevention recommendations, including the timing of vaccination of pregnant women and the recommendation for infant nirsevimab based on maternal RSV vaccination status, as well as the need for coordination of maternal and infant preventive care might also have contributed to an estimated 14.2% of infants reported to have received both nirsevimab and maternal RSV antibody protection, which is not indicated for most infants,” according to the investigators.¹

The CDC conducted an Internet panel survey to collect data on RSV immunization coverage. The survey targeted pregnant women and mothers of newborns to gather insights on vaccination status and factors influencing their decisions regarding RSV immunization.

This report has several limitations, it used a nonprobability sample, which may not accurately represent all US pregnant women due to self-selection bias and the exclusion of those without Internet access. Second, maternal and infant immunization statuses were self-reported, potentially leading to recall or social desirability bias; estimates of maternal vaccination coverage were higher than those from the Vaccine Safety Datalink (VSD), which may have incomplete data. Enhanced provider communication and recommendations is important for increasing RSV immunization rates.

In August, the Ontario Ministry of Health launched a universal public health program to provide nirsevimab to all newborns and high-risk infants born in 2024 during the 2024-2025 RSV season. This marks Ontario's first publicly funded program aimed at protecting infants from RSV.²

The initiative follows recommendations from the National Advisory Committee on Immunization (NACI), emphasizing the significant impact of RSV on infants and healthcare resources. Almost all children are infected by age two, with many severe cases occurring in previously healthy infants. A recent study indicated that nirsevimab reduced RSV-related hospitalizations in infants under six months by 82%.²

The new program aims to improve health outcomes for infants and alleviate pressure on the healthcare system during the RSV season.² The US CDC, alongside the American College of Obstetricians and Gynecologists, provides resources to aid healthcare providers in discussing the importance of RSV immunization with patients, potentially leading to higher protection rates against severe RSV disease in infants.

References

1. Razzaghi H, Garacci E, Kahn KE, et al. Maternal Respiratory Syncytial Virus Vaccination and Receipt of Respiratory Syncytial Virus Antibody (Nirsevimab) by Infants Aged <8 Months — United States, April 2024. MMWR Morb Mortal Wkly Rep 2024;73:837–843. DOI: http://dx.doi.org/10.15585/mmwr.mm7338a2

2. Santofi. Ontario Ministry of Health Announces a Universal Public Program with Beyfortus® this RSV Season. PRNewswire. Published July 25, 2025. Accessed September 30, 2024. https://prnmedia.prnewswire.com/news-releases/ontario-ministry-of-health-announces-a-universal-public-program-with-beyfortus-r-this-rsv-season-871818499.html