During the 2023-2024 respiratory syncytial virus (RSV) season, eight in 10 infants received protection against the virus, marking a significant achievement in pediatric health. The findings, published in JAMA Network Open, shed light on the adoption of two RSV prevention methods: RSVpreF, a maternal vaccine, and nirsevimab, a monoclonal antibody for infants under eight months old.

The study, led by Dr. Karen B. Jacobson from Kaiser Permanente Northern California, analyzed data from electronic medical records of 17,251 infants born between October 17, 2023, and March 31, 2024. RSVpreF became available on October 25, 2023, shortly after nirsevimab's introduction on October 17. Researchers found that 33.9% of infants were exposed to RSVpreF at a median gestational age of 34 weeks, while 40.9% of infants received nirsevimab at a median age of four days. Only 2.7% of infants were exposed to both protective measures, with higher proportions among preterm infants and those admitted to neonatal intensive care units.

The study revealed disparities in RSV protection based on maternal age and ethnicity. Infants born to mothers under 25 years of age were less likely to receive RSVpreF but were more likely to receive nirsevimab than those born to mothers aged 35 and older. Additionally, infants of Asian mothers showed the highest protection rates (86.7%), while infants of Black mothers had the lowest (70.2%).

The availability of both RSV protection methods may have contributed to the increased protection rates, potentially addressing disparities in access to preventive measures. However, the study emphasizes the need for further efforts to ensure equitable healthcare outcomes across all demographic groups.

The research team disclosed potential conflicts of interest, as several authors reported affiliations with pharmaceutical companies Pfizer and Sanofi, which manufacture RSVpreF and nirsevimab, respectively. Despite these disclosures, the findings provide valuable insights into improving RSV prevention strategies and reducing healthcare inequities. This study highlights the critical role of accessible and diverse prevention tools in safeguarding infant health.