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Beyfortus
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What parents need to know about Beyfortus® (nirsevimab-alip)
50 mg and 100 mg injection

Beyfortus can help prevent serious lung infections, like pneumonia caused by RSV, in babies under 1 year of age born during or entering their first RSV season.

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Reduced chance of needing medical care due to RSV

This can include trips to the doctor, urgent care, ER, or hospital.
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Demonstrated safety and efficacy in babies under age 1

The safety of Beyfortus was found to be similar to placebo in clinical studies. Mild to moderate side effects were seen in about 1 in 100 children. The most common side effects of Beyfortus include rash and pain, swelling, or hardness at the site of your baby’s injection. Serious allergic reactions have happened. These are not all the possible side effects of Beyfortus.
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A breakthrough decades in the making

For almost 60 years, scientists have been trying to develop prevention for RSV disease. In 2016, Beyfortus started its first major clinical trial in babies.

Recommended by the American Academy of Pediatrics (AAP)

Beyfortus has also been added to the approved immunization schedule. This means that it may be available at no cost for parents through the Vaccines for Children (VFC) program and many private health insurance companies.

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How Beyfortus works

Beyfortus is a preventative antibody that gives babies the protection against RSV they lack. Antibodies are made naturally by our immune system to fight viruses. But a baby’s immune system might not be strong enough by itself to make enough antibodies to fight RSV. This is where preventative antibodies can add more protection. Beyfortus may not protect all children.

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Your baby gets Beyfortus

Depending on when they're born, your baby will receive Beyfortus at birth or at a regular checkup during or entering their first RSV season.

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A boosted immune system

Beyfortus gives your baby the antibodies they lack while their immune system is maturing.

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An extra layer of protection

If your baby comes into contact with RSV, the preventative antibodies in Beyfortus stick to the surface of the virus to help prevent it from infecting the lungs.

When can my baby get Beyfortus?

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If your baby is born during RSV season (fall through spring)

  • Beyfortus should be given at birth.
  • If not given in the hospital, they should receive it at their first doctor’s visit.
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If your baby is born in the
spring or summer

  • Your baby can get Beyfortus at a regular checkup, typically just before RSV season.
  • They can get their injection at the same time as other routine childhood vaccines.

How you can take action today

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Additional questions you may have about Beyfortus

Vaccines are like self-defense instructors. They teach the immune system to create its own antibodies. Beyfortus is a preventative antibody, which acts like a bodyguard. It gives the protection that a maturing immune system can’t yet provide for itself.

While a baby’s immune system is developing, Beyfortus helps to protect against RSV lung infection requiring medical care. Medical care can include trips to the doctor, urgent care, ER, or hospital.

Beyfortus reduces the risk of severe RSV disease by about 80%, according to the CDC.

Most babies will receive a single dose.

An additional dose of Beyfortus may be needed for children up to 24 months of age who remain at increased risk for severe RSV disease in their second RSV season. For children undergoing cardiac surgery with cardiopulmonary bypass, an additional dose of Beyfortus is recommended as soon as the child is stable after surgery.

Your child should not take Beyfortus if your child has a history of serious allergic reactions to nirsevimab-alip or any of the ingredients in Beyfortus.

Before your child receives Beyfortus, tell your healthcare provider about all of your child’s medical conditions, including if your child:
  • has ever had a reaction to Beyfortus.
  • has bleeding or bruising problems. If your child has a problem with bleeding or bruises easily, an injection could cause a problem.


Tell your healthcare provider about all the medicines your child takes, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Your infant should not receive a medicine called palivizumab if they have already received Beyfortus in the same RSV season.

The development of Beyfortus was nearly 7 years in the making with the first major clinical trial in babies in 2016. Clinical trials have included healthy babies born at term, premature babies, and babies with underlying health conditions.

The most common side effects of Beyfortus include rash and pain, swelling, or hardness at the site of your baby’s injection. In clinical trials, 1.2% of babies who received Beyfortus reported any side effects.

These are not all the possible side effects of Beyfortus. Call your healthcare provider if you have questions about side effects.

Serious allergic reactions have happened with Beyfortus. Get medical help right away if your child has any of the following signs or symptoms of a serious allergic reaction:
  • swelling of the face, mouth, or tongue
  • difficulty swallowing or breathing
  • unresponsiveness
  • bluish color of skin, lips, or under fingernails
  • muscle weakness
  • severe rash, hives, or itching

Beyfortus has been added to the approved immunization schedule for babies and can be given at the same time as other routine childhood vaccines.

Beyfortus is usually injected in your baby’s thigh.

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