72% of Infants Immunized Against Respiratory Syncytial Virus

A recent study led by Stephanie A. Irving from the Kaiser Permanente Center for Health Research in Portland, Oregon, has revealed that 72% of infants in the United States were immunized against Respiratory Syncytial Virus (RSV) between September 22, 2023, and March 31, 2024. The research analyzed data from 43,722 pregnancies resulting in 36,949 eligible infants born at or after 32 weeks of gestation.

Using electronic health records and state immunization information systems, the study tracked maternal RSV vaccination and infant administration of nirsevimab — a monoclonal antibody designed to prevent severe RSV infection. Infants were considered immunized if they had received either antenatal vaccination via their mothers or a direct nirsevimab dose, according to Dermatology Advisor.

The findings show encouraging overall coverage, especially among infants born to non-Hispanic Asian mothers, who had the highest immunization rate at 84%. However, the study also revealed significant racial disparities. Only 60% of infants born to non-Hispanic Black or non-Hispanic Middle Eastern or North African mothers received RSV protection.

Immunization rates also varied by the infants' birth months, ranging from 59% to 78%. Notably, nirsevimab was administered more frequently to infants born earlier in the RSV season, suggesting that timing played a role in access or uptake of the protective measure.

Despite overall positive trends, researchers expressed concern about the substantial proportion of infants who remain unprotected. “More than a quarter of infants enrolled in these health care systems remained unprotected from severe RSV, including 40 percent of infants born to non-Hispanic Black and non-Hispanic Middle Eastern or North African mothers,” the authors noted.

The study highlights the need to address inequities in RSV immunization, particularly among racially and ethnically diverse communities. Researchers recommend further investigation into the systemic and logistical factors contributing to these disparities, such as healthcare access, awareness, and provider practices.

The insights from this large-scale study provide valuable guidance for improving outreach and vaccine distribution strategies, ensuring more equitable protection for all infants against RSV.