New York State Department of Health Highlights Study With Centers for Disease Control and Prevention (CDC) Showing Respiratory Syncytial Virus Prevention Products Protect Infants

Morbidity and Mortality Weekly Report Finds Significantly Lower RSV-Associated Hospitalizations Among Infants and Children Who Received Monoclonal Antibody or their Mother Received the Vaccine

Findings Show New York is Reducing Risk of RSV Hospitalizations in Infants

New York State Participated in Analysis with CDC as Part of CDC's Emerging Infections Program (EIP)

ALBANY, N.Y. (May 9, 2025) – The New York State Department of Health is highlighting a new Centers for Disease Control and Prevention (CDC)-led report, co-authored by the Department, showing that two respiratory syncytial virus (RSV) prevention products – the maternal RSV vaccine and the long-acting monoclonal antibody nirsevimab – are effective in protecting infants from severe illness.

The paper, published in CDC's Morbidity and Mortality Weekly Report (MMWR), compared hospitalization rates in children during the 2024-2025 RSV season with earlier respiratory virus seasons and found that hospitalization rates were significantly lower for infants who received RSV prevention products. Findings from this study indicate New York is on the right path in reducing the risk of RSV hospitalizations in infants.

"RSV can be dangerous for babies and is a leading cause of hospitalization in babies," State Health Commissioner Dr. James McDonald said. "The good news is that we now have two widely available RSV prevention products that are protecting little ones from serious illness or even death. This is a major step forward in protecting our youngest, most vulnerable New Yorkers. We are pleased to have contributed to this important research and among the states leading the way in promoting access to these protections. I thank the dedication of our Department staff, including the NYSDOH Emerging Infections Program, for their contributions to this important analysis that shows the maternal vaccine, and monoclonal antibodies are ensuring babies are protected against RSV."

Respiratory syncytial virus is a common respiratory infection that usually causes mild, cold-like symptoms but can be dangerous for very young children. RSV is the leading cause of hospitalization among U.S. infants, with the youngest infants at highest risk for severe disease, such as hospitalization or ICU admission.

The 2024-2025 RSV season is the first with widespread availability of the maternal RSV vaccine and nirsevimab, a long-acting preventative antibody given to infants. Both protect infants from severe RSV infection; the maternal vaccine is given to the mother during pregnancy, while nirsevimab is a one-time injection given directly to infants and provides protection throughout the entire season.

The analysis in the MMWR compared RSV-associated hospitalizations in two surveillance networks during the 2024-2025 season to the 2018-2020 season, prior to the availability of the RSV vaccine or long-acting preventive antibody.

The data show significant reductions in hospitalizations for infants who received either form of protection, including the following:

  • The data show nationally that RSV hospitalization rates in babies under 8 months substantially decreased compared with prior years.
  • Among NYS infants, RSV hospitalization rates in babies under 8 months decreased by 70 percent.
  • The largest reduction in hospitalization rates nationally was among babies under 3 months - hospitalizations for babies under 3 months was cut by at least half.
  • Among NYS infants, RSV hospitalization rates among babies under 3 month was reduced by 76 percent.

In August 2024, Commissioner McDonald issued a statewide standing order to allow pharmacists to administer RSV vaccines for pregnant people and older adults. The order allows individuals to go to a participating pharmacy and receive a vaccine without a separate prescription from their physician.

CDC recommends the maternal RSV vaccine during pregnancy or RSV antibody after birth to protect infants from severe RSV. The maternal RSV vaccine (Pfizer's Abrysvo) is recommended for pregnant women who are 32–36 weeks pregnant during September–January.

Nirsevimab, a preventative antibody, is recommended for infants under 8 months born to mothers who did not receive a maternal RSV vaccine (Pfizer's Abrysvo) during pregnancy during their first RSV season. A nirsevimab dose should be given to babies shortly before the RSV season, or within one week after birth if born during October to March in most of the U.S. It is also recommended for children aged 8-19 months who are at increased risk of severe RSV disease and who are entering their second RSV season.

The New York State conducted targeted outreach to birthing hospitals to enroll in the Vaccines for Children Program (VFC) to promote RSV protection to infants prior to hospital discharge. Two-thirds of birthing hospitals enrolled in VFC for the 2024-2025 season. Overall, nearly 75,000 infants less than 8 months of age in New York State (including New York City) received a dose of nirsevimab during the 2024-2025 RSV season (approximately 34 percent).

New York State participated in this analysis as part of the CDC's Emerging Infections Program (EIP) – a public health surveillance system created by the CDC in 1995. There are 12 EIP sites across the country and the New York State Department of Health has been an EIP site since 1997.

The Department, including the Wadsworth Center, collaborates with the academic partner the University of Rochester Medical Center (URMC), as well as hospitals, laboratories, and local health departments in upstate New York to conduct population-based surveillance of illnesses caused by laboratory-confirmed respiratory viruses (RESP-NET), foodborne pathogens (FoodNet), tick-borne pathogens (TickNet) and select invasive bacteria (ABCs). URMC conducts surveillance of healthcare associated infections-community interface (HAIC), fungal diseases and human papillomavirus (HPV-IMPACT).

More information about the Emerging Infections Program can be found here and here.

More information about RSV, including symptoms, how it's spread and how to prevent RSV can be found here.