Massachusetts Department of Public Health Advises Extending RSV Immunizations for Infants for an Additional Month

Massachusetts Department of Public Health Advises Extending RSV Immunizations for Infants for an Additional Month 

 

Recommendation extends the immunization window through April 30 because of ongoing elevated RSV activity 

BOSTON (March 24, 2026) – The Massachusetts Department of Public Health (DPH) issued a clinical advisory to health care providers recommending that respiratory syncytial virus (RSV) monoclonal antibody immunizations continue to be administered to eligible infants through April 30, 2026, in response to ongoing RSV activity across the state and throughout the region. 

 

RSV monoclonal antibody immunizations are typically administered from October through March. The current RSV season, however, began later than usual, and it is continuing further into the spring. Surveillance data show sustained RSV activity in Massachusetts and surrounding states, prompting the extension of the immunization window beyond the usual March 31 endpoint. 

 

“RSV continues to circulate at meaningful levels later into the spring than we typically see,” said Public Health Commissioner Robbie Goldstein, MD, PhD. “Public health guidance must reflect the reality of the moment. Extending access to these preventive tools is about matching data and risk with proven measures that can prevent and protect our youngest residents from the most severe effects of this illness.” 

 

RSV, a common respiratory virus, is a leading cause of hospitalization among infants in the United States. While RSV often begins as a mild, cold-like illness, it can lead to serious conditions such as bronchiolitis and pneumonia. This illness can be particularly problematic for very young infants and those with underlying medical conditions that make them especially vulnerable to the disease.  

 

In the clinical advisory, DPH urged clinicians to assess the RSV immunization status of infants and encourage monoclonal antibody protection for those who are eligible and have not yet received the immunization during the current season. 

 

Infants younger than 8 months of age should receive RSV monoclonal antibody immunization if their mother was not vaccinated during pregnancy, if maternal vaccination status is unknown, or if they were born within 14 days of maternal vaccination. Certain children aged 8 to 19 months are at increased risk for severe RSV disease – including those with chronic lung disease or prematurity, severe immunocompromise, cystic fibrosis, or other qualifying conditions – and should also receive RSV immunization.  

 

“RSV remains the leading cause of serious respiratory tract infection in infants, and too many young children still are at risk of preventable hospitalization,” said Larry Madoff, MD, Medical Director of DPH’s Bureau of Infectious Disease and Laboratory Sciences. “We have a safe, effective way to reduce that risk, and extending access now will help to protect more infants while RSV continues to circulate. We will continue to closely monitor RSV trends and will adjust our approach based on real-time data and what we are seeing in communities across the Commonwealth.”  

 

This extension applies only to infant monoclonal antibody immunization for the 2025-2026 RSV season. The seasonal window for maternal RSV vaccination – September 1 through January 31 – remains unchanged and should not be extended, as maternal vaccination timing cannot be adjusted once pregnancy has progressed. 

 

In addition to infant protection, RSV vaccination is recommended for older adults. Adults aged 75 and older and those aged 50 to 74 with certain underlying conditions should receive a one-time RSV vaccine dose. Unlike infant immunization, RSV vaccination for older adults is not seasonal and can be administered year-round. 

 

For more information, visit the Massachusetts Department of Public Health Respiratory Illness Dashboard and review current American Academy of Pediatrics guidance on RSV prevention.