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pronounced as (nir sev' i mab)

Why is this medication prescribed?

Nirsevimab-alip is used to prevent lung disease caused by Respiratory Syncytial Virus (RSV) infection in neonates or infants in their first RSV season or for children up to 24 months in their second RSV season and are at risk of severe disease. Nirsevimab-alip is in a class of medications called monoclonal antibodies. It works by preventing RSV from infecting cells and causing disease.

How should this medicine be used?

Nirsevimab-alip comes as a solution (liquid) to be given intramuscularly (into the muscle) by a doctor or nurse. It is usually given as a single dose. However, for children who are receiving heart surgery involving a bypass machine, a second dose may be given.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before receiving nirsevimab-alip,

  • tell your doctor and pharmacist if your child is allergic to nirsevimab, any other medications, or any of the ingredients in nirsevimab-alip injection. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are giving or plan to give to your child.
  • tell your doctor if your child has or has ever had a bleeding or clotting disorder or if you were told that they have low platelets or if they are receiving blood thinners.

What special dietary instructions should I follow?

Unless your doctor tells you otherwise, continue normal diet.

What side effects can this medication cause?

Nirsevimab-alip may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • rash
  • pain, swelling or hardness at the injection site

Some side effects can be serious. If your child experiences any of these symptoms call your doctor immediately or get emergency medical treatment:

  • swelling of the face, tongue and mouth
  • difficulty swallowing or breathing
  • unresponsiveness
  • bluish color of skin, lips or fingernails
  • muscle weakness
  • severe rash, hives or itching

Nirsevimab-alip may cause other side effects. Call your doctor if you notice any unusual problems after receiving this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( or by phone (1-800-332-1088).

What other information should I know?

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Brand names

  • Beyfortus®
Last Revised - 08/15/2023