Nirsevimab is a man-made antibody that helps protect the body against respiratory syncytial virus (RSV) infection for up to 5 months.

Nirsevimab is used to prevent lung disease caused by respiratory syncytial virus in newborn baby and children up to 24 months old.

Nirsevimab may also be used for purposes not listed in this medication guide.

Nirsevimab should not be given to a child who has had a severe allergic reaction to it.

Your child should not receive a medicine called palivizumab if the child already received nirsevimab in the same respiratory syncytial virus (RSV) season.

Nirsevimab is given once as an injection (shot) into the leg muscle. A healthcare provider will give this injection.

If your child remains at increased risk for getting RSV infection or has heart surgery, your child may receive another dose of this medicine.

Usual Pediatric Dose for Respiratory Syncytial Virus:

Recommended dosage:
-Neonate and infants born during or entering their first respiratory syncytial virus (RSV) season: 50 mg intramuscularly once (for children less than 5 kg) or 100 mg intramuscularly once (for children 5 kg or greater)

-Children up to 24 months of age who remain at increased risk for severe RSV in their second RSV season: a single 200 mg dose intramuscularly, administered as two 100 mg injections (2 x 100 mg).

-Children undergoing cardiac surgery with cardiopulmonary bypass: an additional dose is recommended via intramuscular route as soon as the child is stable after surgery to ensure adequate vaccine serum levels.
--In the first RSV season: If surgery is within 90 days after receiving the vaccine, the additional dose should be based on current body weight. See above for body weight dosing. If more than 90 days have elapsed since receiving the vaccine, the additional dose should be 50 mg regardless of body weight.
--In the second RSV season: If surgery is within 90 days after receiving the vaccine, the additional dose should be 200 mg, regardless of body weight. If more than 90 days have elapsed since receiving the vaccine, the additional dose should be 100 mg regardless of body weight.

Use: For active immunization for the prevention of lower respiratory tract disease (LRTD) caused by respiratory syncytial virus (RSV) in neonates and infants born during or entering their first RSV season and children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season.

Your child should not receive nirsevimab if the child has ever had a life-threatening allergic reaction to any component of nirsevimab or to antibodies called immunoglobulins.

Your child should not receive a medicine called palivizumab if the child already received nirsevimab in the same RSV season.

Tell your child's doctor if the child has bleeding or bruising problems.

Nirsevimab is used as a single dose and does not have a daily dosing schedule.

An overdose of nirsevimab is unlikely to occur.

Follow the doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of the face, lips, tongue, or throat.

Call the doctor at once if your child has:

• muscle weakness;

• trouble swallowing;

• blue lips or fingernails; or

• bluish color of skin.

Common side effects of nirsevimab may include:

• hard painful lump (induration) around where the medicine was injected; or

• rash, or swelling where the injection was given.

This is not a complete list of side effects and others may occur. Call your child's doctor for medical advice about side effects. You may report side effects to FDA at 1 800 FDA 1088.

Other drugs may affect nirsevimab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell the doctor about all other medicines your child uses.