CDC Announces Shortage of Nirsevimab, Used for RSV

The CDC announced on Monday, October 23, 2023, that there is a limited supply of nirsevimab, a monoclonal antibody that is recommended for use in infants to prevent lower respiratory tract disease associated with respiratory syncytial virus (RSV).

RSV is the most common cause of respiratory infection in the United States, primarily in infants within the first year of their life. The FDA approved nirsevimab, also known as Beyfortus, in July 2023 to give infants passive immunization against lower respiratory tract infections brought on by RSV. The CDC Advisory Committee on Immunization Practices (ACIP) recommended the antibody for infants younger than 8 months during or entering their first season of RSV, as well as infants aged 8 to 19 months who were at risk for severe RSV. RSV transmission is expected to increase nationwide within the next 1 to 2 months.

According to the CDC’s announcement, there is a limited supply of nirsevimab from the manufacturer for the 2023-2024 RSV season, with prefilled syringes of 100-mg doses in especially short supply. Although the shortage of of 50-mg dose prefilled syringes is not as severe, supply will likely be limited during the RSV season. The CDC is working with the manufacturer on strategies to boost the supply of nirsevimab, but in the meantime issued several suggestions for both health care providers and the public on how to adapt to the shortage.

The CDC is currently recommending that the ACIP recommendations remain unchanged for infants who weigh less than 5 kg. Infants born before October 2023 should receive a 50-mg dose now and infants born in October and later this RSV season should receive a 50-mg dose within their first week of life. For infants who weigh 5 kg or more, health care providers should prioritize giving the 100-mg dose to those at highest risk of severe disease. This includes all infants younger than 6 months, American Indian and Alaska Native infants younger than 8 months, and infants aged 6 to 8 months who have conditions that give them a higher overall risk of severe RSV.

Doctors should use palivizumab instead of nirsevimab in eligible children aged 8 to 19 months, the CDC noted, but nirsevimab should be offered to American Indian and Alaska Native infants aged 8 to 19 months who are not eligible for palivizumab. Recommendations from the American Academy of Pediatrics should be followed when offering palivizumab to infants younger than 8 months. Doctors should also avoid using two 50-mg doses for any infants who weigh 5 kg or more in order to preserve the supply as much as possible. Pregnant women should also be encouraged to receive Pfizer’s RSVpreF vaccine (Abrysvo) to protect their child from RSV once born. Administration of both the preventive vaccine in pregnant women and nirsevimab in the infant is not needed; a single dose of 1 vaccine is sufficient.

The CDC also recommends that the public take precautions to limit the spread of RSV. During pregnancy, patients should ask their health care provider about receiving an RSV vaccine to protect their child from the virus. Parents should also ask about the availability of nirsevimab for their child.

Reference

Limited availability of nirsevimab in the United States—interim CDC recommendations to protect infants from respiratory syncytial virus (RSV) during the 2023-2024 respiratory virus season. News release. CDC. October 23, 2023. Accessed October 24, 2023. https://emergency.cdc.gov/han/2023/han00499.asp