The winter of 2024-2025 has brought a remarkable decrease in infant hospitalizations due to respiratory syncytial virus (RSV) in the United States, thanks to the groundbreaking introduction of a new vaccine and antibody treatment, recent data from the US Centers for Disease Control and Prevention (CDC) reveals.

In a significant move, the US Food and Drug Administration (FDA) approved an RSV maternal vaccine aimed at protecting infants right from birth. Administered to pregnant individuals at 32-36 weeks, this innovative vaccine was rolled out just in time for the RSV season.

According to national immunization survey data, the percentage of US infants aged 0-7 months receiving protection through either the new maternal vaccination or nirsevimab—a cutting-edge monoclonal antibody—soared to an impressive 66% by February 2025, a remarkable jump from just 30% in October 2024.

A Notorious Threat to Infants

RSV has long been a formidable adversary, causing an astounding 33 million cases of lower respiratory infections and 3.6 million hospitalizations annually in children under five, predominantly during their first year. Disturbingly, RSV is the second leading cause of infant mortality worldwide, surpassed only by malaria, with over 100,000 fatalities among children under five each year.

Most tragically, more than 99% of these deaths occur in lower- and middle-income countries, particularly in Africa, where many children succumb before reaching medical facilities.

A Swift Decline in Hospitalizations

CDC researchers meticulously analyzed hospitalization rates from two distinct RSV surveillance networks—RSV-NET and NVSN. They compared data from the 2024-2025 RSV season with pre-pandemic statistics from 2018 to 2020, revealing astonishing drops in hospitalizations: a 52% decrease in RSV-NET and 45% in NVSN for newborns aged 0-2 months.

However, excluding data from an NVSN site in Houston—where the RSV season commenced prior to the vaccine's availability—showed even more dramatic results, with a staggering 71% drop in hospitalizations.

Looking Ahead: Global Hope

The World Health Organization (WHO) recently took a crucial step by prequalifying the maternal RSV vaccine, paving the way for international health agencies to procure it for national immunization programs. This is especially promising for lower-income countries grappling with the devastating burden of RSV.

With the potential for wider global availability, experts anticipate that increased usage of RSV prevention strategies in upcoming seasons could lead to even greater reductions in pediatric RSV-related hospitalizations, offering new hope for families everywhere.