(NewsNation) — The Centers for Disease Control and Prevention alerted health care providers on protecting infants from RSV after learning that only a limited supply of a treatment called nirsevimab, a special antibody that helps prevent RSV-related problems in infants, is available. 

The update coincides with a surge in RSV cases in certain regions of the United States as the cold and flu season begins, posing a challenging situation for many pediatricians. 

The CDC suggests giving 100 mg doses of nirsevimab be rationed by giving them only to infants at the highest risk of severe RSV disease. These high-risk groups include infants less than 6 months old and those with certain medical conditions that make them more vulnerable to severe RSV issues.  

The guidelines for using 50mg doses of nirsevimab haven’t changed for now. It’s also advised not to give two 50mg doses to infants weighing over 11 pounds to make sure there’s enough for those weighing less than 11 pounds. 

The company making nirsevimab has reported a shortage, especially of the 100mg prefilled syringes used for larger infants. There may also be limited availability of 50mg syringes. 

RSV is a leading cause of infant hospitalizations, with the highest risk for those younger than 3 months. To prevent severe RSV disease, efforts focus on immunization through maternal vaccines and monoclonal antibodies for young infants. 

In July 2023, the FDA approved nirsevimab, also known as BeyfortusTM, made by Sanofi and AstraZeneca. This long-acting monoclonal antibody is recommended for infants less than 8 months old in their first RSV season and for children aged 8-19 months at higher risk entering their second RSV season.