Beyfortus (nirsevimab-alip) is a brand-name drug prescribed to help prevent respiratory syncytial virus (RSV) disease in certain children. Beyfortus comes as a solution for intramuscular injection that’s given by a healthcare professional.
Beyfortus is a biologic and belongs to a drug class called monoclonal antibodies. Beyfortus isn’t available in a biosimilar version.
Keep reading for specific information about the dosage of Beyfortus, including its strengths and how the medication is given. For a comprehensive look at Beyfortus, see this article.
Note: This article describes typical dosages for Beyfortus provided by the drug’s manufacturer. However, your child’s doctor will prescribe the Beyfortus dosage that’s right for your child.
Below is information about the recommended dosages for Beyfortus.
Beyfortus form
Beyfortus comes as a solution in a single-dose prefilled syringe. It’s given as an intramuscular injection by a doctor or another healthcare professional.
Beyfortus strengths
Beyfortus comes in two strengths:
- 50 milligrams (mg) per 0.5 milliliters (mL) solution
- 100 mg/1 mL
Typical dosages
The following information describes dosages that are commonly prescribed.
Dosage for respiratory syncytial virus
Beyfortus is prescribed to help prevent a serious lung disease caused by respiratory syncytial virus (RSV) infection in:
- children up to age 12 months born during or entering their first RSV season*
- children up to age 24 months who still have an increased risk† of severe RSV disease through their second RSV season
The table below shows the recommended Beyfortus dosages:
| Age | Body weight | Recommended dosage |
|---|---|---|
| up to 12 months | less than 5 kilograms (kg)‡ | 1 injection of 50 mg |
| up to 12 months | 5 kg and greater | 1 injection of 100 mg |
| up to 24 months, with increased risk of RSV disease† | doesn’t apply | 2 injections of 100 mg, given at the same appointment |
Your child’s doctor will determine the dosage that’s right for your child.
Talk with your child’s doctor if you have questions about the dosage they recommend.
* RSV season is the time of year when RSV infections are most common. This is usually from fall through spring. Your child’s doctor can tell you when RSV season starts in your area.
† Children with certain medical conditions have an increased risk of severe RSV disease. Examples include long-term lung disease or congenital heart disease.
‡ One kg equals about 2.2 pounds (lb).
The Beyfortus dosage prescribed will depend on several factors. These include:
- your child’s body weight
- whether it’s their first or second RSV season (see “Beyfortus dosage” just above for details)
- whether they’ve had heart surgery
Dosage adjustments
Your child’s doctor may need to give an extra dose of Beyfortus if your child had heart surgery with cardiopulmonary bypass. (This is a technique in which a machine temporarily takes over heart and lung function during surgery.)
Be sure to tell your doctor about all medications your child takes and any health conditions your child may have.
Beyfortus comes as a solution in a single-dose prefilled syringe. A doctor or another healthcare professional gives the dose as an intramuscular injection, usually in the thigh muscle. If your child requires two injections, each one will be given in a different spot at the same appointment.
Your child will receive Beyfortus at their doctor’s office or during a hospital stay.
If you have questions about how Beyfortus is given, talk with your child’s doctor.
ACCESSIBLE DRUG LABELSSome pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.
Below are some frequently asked questions about Beyfortus.
How long does it take for Beyfortus to start working?
Beyfortus starts working within hours after your child receives their dose. Beyfortus is prescribed to certain children to help prevent respiratory syncytial virus (RSV) infection. For details on dosing, see the “Beyfortus dosage” section above.
In clinical trials, a single dose of Beyfortus offers protection from RSV infection for about 5 months.
Talk with your child’s doctor if you have questions about what to expect with Beyfortus.
Can Beyfortus be used for the flu? If so, what’s the dosage?
No, Beyfortus isn’t used to treat or help prevent the flu. Some symptoms of RSV infection are similar to those of the flu. However, Beyfortus is prescribed to certain children specifically to help prevent RSV infection. It doesn’t work against other viruses.
Since Beyfortus isn’t used for the flu, the manufacturer doesn’t provide recommended dosages for this purpose. However, vaccines that help prevent the flu, such as Afluria or Fluarix, are available. In addition, Tamiflu (oseltamivir) is a prescription drug that treats the flu.
For information about prevention and treatment options for RSV and the flu, talk with your child’s doctor.
Can Beyfortus be given with other childhood immunizations?
Yes, your child may receive Beyfortus alongside other childhood immunizations.
Beyfortus is a medication that helps prevent RSV infections in certain children ages 2 years and younger. Beyfortus is one of the immunizations the
Your child’s doctor will determine whether your child can receive Beyfortus alongside their other recommended immunizations.
The dosages in this article are the typical dosages provided by the drug’s manufacturer. If your child’s doctor recommends Beyfortus, they’ll prescribe the dosage that’s right for your child. If you have questions about the dosage of Beyfortus that’s best for your child, talk with your child’s doctor.
Besides learning about dosage, you may want other information about Beyfortus. These additional articles might be helpful:
- More about Beyfortus. For information about other aspects of Beyfortus, refer to this article.
- Details about respiratory syncytial virus (RSV). To learn more about immunization against RSV and other infections, see our list of articles on:
Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.