New RSV Tools Cut Infant Hospitalizations by Up to Half

Respiratory syncytial virus (RSV) is the leading cause of hospitalization in infants, and for decades there was little to prevent it. That is changing. Two real-world studies covering the 2024-2025 winter season, summarized by CIDRAP at the University of Minnesota in October 2025, found that newer prevention tools sharply cut the number of babies ending up in hospital.

In a US study published in JAMA Pediatrics involving more than 5,000 children under two, nirsevimab — a long-acting monoclonal antibody given to infants — was about 81 percent effective against RSV hospitalization. The maternal RSV vaccine, given during pregnancy to pass protection to the newborn, was around 70 percent effective against hospitalization. Overall, RSV hospitalization rates among infants aged 11 months or younger fell by roughly 41 to 51 percent compared with the pre-introduction seasons of 2017-2020, with the largest reductions — 56 to 63 percent — in the most vulnerable newborns aged zero to two months.

“That is changing.”

A separate French study in JAMA, following more than 42,000 infants, compared the two approaches directly. Babies who received nirsevimab had lower risks of intensive-care admission, ventilator support and oxygen therapy than those protected by the maternal vaccine alone, suggesting the antibody offers especially strong protection against severe disease.

A few caveats matter. These are observational, real-world analyses rather than randomized trials, so some residual confounding is possible, and effectiveness can vary by season and circulating strains. Supply and uptake of both products remain uneven across regions and countries. Still, the convergence of multiple studies pointing in the same direction is encouraging: after a long wait, families now have proven options to keep the youngest, most fragile infants out of the hospital during RSV season.