Atlanta, May 9 — The number of newborns hospitalized with RSV, a common but dangerous respiratory virus, has dropped sharply during the current season, thanks to new preventive tools, the Centers for Disease Control and Prevention (CDC) reported Thursday.
RSV, or respiratory syncytial virus, is the leading cause of infant hospitalizations in the United States. Each year, it sends an estimated 58,000 to 80,000 children under age five to the hospital. Newborns under two months old are especially vulnerable. The virus usually spreads in fall and peaks in winter.
But the 2024–2025 season showed a major shift. This year marked the introduction of two new protections: a maternal vaccine and an antibody treatment for infants.
One tool, Pfizer’s Abrysvo, is a vaccine given to pregnant people during their third trimester if it aligns with RSV season, typically September through January. It helps pass protective antibodies to the baby before birth.
The other, nirsevimab, is a long-acting monoclonal antibody treatment. It is given to babies under eight months old at the start of their first RSV season, especially if they are born outside the maternal vaccine window.
The CDC analyzed RSV hospitalization data from two national surveillance systems—RSV-NET and NVSN—comparing this season’s numbers to pre-pandemic seasons between 2018 and 2020.
Among newborns aged 0 to 2 months, RSV hospitalizations fell 52% in RSV-NET and 45% in NVSN. When Houston data was excluded from NVSN—because the RSV season there began before the rollout of the new interventions—hospitalizations dropped by 71%.
For infants aged 0 to 7 months, RSV-NET reported a 43% decline, while NVSN saw a 28% drop. Excluding Houston from NVSN pushed the reduction to 56%.
Researchers also examined RSV hospitalizations among children up to age five, a group not eligible for the new protections. In this group, hospitalizations were actually higher than before the pandemic. That suggests this season was more severe overall, and the recorded drop among infants might underestimate the benefits of the new measures.
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