RSV Vaccine for Babies? What Parents Should Know About the RSV Shot

Written & Medically Reviewed by Dr. G
Board-Certified Pediatrician · Nearly 40 Years of Pediatric Experience
About Dr. G

Quick Answer

Parents often call it the “RSV vaccine for babies,” but the RSV protection given directly to babies is actually a long-acting antibody, not a vaccine. Babies may receive nirsevimab (Beyfortus) or clesrovimab (Enflonsia). Another option is for the mother to receive the Abrysvo RSV vaccine during pregnancy, allowing protective antibodies to pass to the baby before birth. Most babies do not need both approaches.

Key Takeaways

  • There is currently no RSV vaccine given directly to babies.
  • Babies can receive a long-acting RSV antibody called nirsevimab (Beyfortus) or clesrovimab (Enflonsia).
  • Pregnant women may receive Pfizer's Abrysvo during weeks 32 through 36 of pregnancy to help protect their baby.
  • Most babies need either maternal vaccination or an infant RSV antibody—not both.
  • RSV prevention is especially important because infants are among those at greatest risk for severe RSV illness.

If you have heard parents, friends, or even family members talking about the “RSV vaccine for babies,” it is understandable to be confused. RSV prevention has changed considerably in recent years, and several different products are now available.

The simplest way to understand it is this: we can protect a baby either before birth through maternal vaccination or after birth by giving the baby protective antibodies directly.

Both strategies are designed primarily to reduce a baby's risk of becoming seriously ill from respiratory syncytial virus, or RSV.

Why Do Babies Need Protection From RSV?

RSV is an extremely common respiratory virus. For many older children and adults, it causes symptoms that resemble an ordinary cold.

Babies—particularly young infants—can become much sicker. RSV can move into the smaller airways of the lungs and cause bronchiolitis or pneumonia. Some babies develop difficulty breathing, trouble feeding, dehydration, or low oxygen levels and may need hospital care.

That is why preventing severe RSV disease during a baby's first RSV season is so important.

Is There an RSV Vaccine for Babies?

No—not in the way most parents mean when they use the word vaccine.

The RSV injections given directly to infants are monoclonal antibodies. They provide ready-made antibodies that can immediately help protect the baby against RSV.

The two long-acting RSV antibodies currently available for infants are:

  • Nirsevimab — brand name Beyfortus
  • Clesrovimab — brand name Enflonsia

You may hear parents or even casual conversations refer to these as an “RSV vaccine” or “RSV shot.” Calling them an RSV shot is understandable, but medically they are antibodies rather than vaccines.

What Is the Difference Between a Vaccine and an RSV Antibody?

A vaccine teaches your immune system to make its own immune response against an infection.

A monoclonal antibody works differently. Instead of asking the baby's immune system to make antibodies, the medication provides the protective antibodies directly.

That means protection begins quickly and can last through much of an RSV season. CDC states that long-acting infant RSV antibodies provide protection for at least five months.

Two Ways to Help Protect a Baby From Severe RSV

Option 1: RSV Vaccination During Pregnancy

Pfizer's Abrysvo is an RSV vaccine recommended during certain pregnancies. The mother's immune system produces antibodies after vaccination, and some of those antibodies cross the placenta to the baby.

In most of the continental United States, CDC recommends one dose of Abrysvo during 32 weeks 0 days through 36 weeks 6 days of pregnancy, generally from September through January.

RSV seasons can differ by location. Areas with different RSV patterns—including some tropical regions—may use different timing, so parents should follow the advice of their obstetric and pediatric healthcare professionals.

Option 2: An RSV Antibody Given to the Baby

A baby can instead receive nirsevimab or clesrovimab. These are given as an injection and provide antibodies directly to the infant.

In most of the United States, infant RSV antibodies are generally given during October through March. Babies born during RSV season can often receive the antibody shortly after birth, ideally during the birth hospitalization when appropriate.

Which Babies Should Receive an RSV Antibody?

An RSV antibody is recommended for babies younger than 8 months who are born during or entering their first RSV season when:

  • The mother did not receive the maternal RSV vaccine during pregnancy;
  • The mother's RSV vaccination status is unknown; or
  • The baby was born within 14 days after the mother received the RSV vaccine.

There are also uncommon situations in which a healthcare professional may recommend an infant antibody even though the mother was vaccinated during pregnancy.

Does My Baby Need Both?

Usually, no.

For most babies, either maternal vaccination during pregnancy or an infant RSV antibody provides the recommended protection.

There are special circumstances in which an infant antibody may still be considered after maternal vaccination. Your baby's pediatrician can determine whether one of those situations applies.

What About a Child's Second RSV Season?

Most healthy children do not need RSV antibody protection for their second RSV season.

However, certain children ages 8 through 19 months who have a higher risk for severe RSV may be recommended to receive nirsevimab before their second RSV season.

This may include some children with chronic lung disease of prematurity, severe immune compromise, severe cystic fibrosis, and American Indian or Alaska Native children.

Clesrovimab is not currently recommended for second-season protection.

Is the RSV Shot Safe for Babies?

Both nirsevimab and clesrovimab have been studied for the prevention of RSV disease in infants and are recommended for eligible babies.

Side effects from infant RSV antibodies are generally mild. CDC notes that they can include pain, redness, or swelling where the injection was given. Serious allergic reactions are uncommon, although they can occur with medications.

Parents should discuss their baby's medical history, previous allergic reactions, and individual circumstances with their pediatric healthcare professional.

Is the RSV Vaccine Safe During Pregnancy?

The RSV vaccine recommended during pregnancy is Pfizer's Abrysvo. CDC recommends it during the specified 32-through-36-week window because available evidence supports that its benefits in preventing severe RSV disease in infants outweigh potential risks.

Other RSV vaccines used in adults, including Arexvy and mResvia, are not approved for use during pregnancy.

What If I Received the RSV Vaccine During a Previous Pregnancy?

This is an important question.

Current CDC guidance does not recommend another maternal RSV vaccine dose during a later pregnancy if the mother received an RSV vaccine during a previous pregnancy.

Instead, the new baby should receive an appropriate infant RSV antibody when eligible.

What Parents Can Do

During pregnancy, ask your obstetric healthcare professional whether maternal RSV vaccination is appropriate based on your gestational age and the time of year.

After your baby is born, ask the pediatrician whether your baby needs nirsevimab or clesrovimab. Be sure to tell the pediatrician whether you received Abrysvo during the current pregnancy and, if so, the date you received it.

When to Call Your Pediatrician

Call your pediatrician if you are unsure whether your baby received RSV protection, whether maternal vaccination provides adequate protection, whether your baby qualifies for an RSV antibody, or if your baby has a medical condition that may increase the risk of severe RSV disease.

If Your Baby Develops RSV Symptoms

RSV prevention greatly reduces the risk of severe disease, but it does not guarantee that a baby will never become infected.

Seek urgent medical care for significant difficulty breathing, pauses in breathing, blue or gray lips or skin, severe dehydration, unusual difficulty waking, or other signs that your baby is seriously ill. A baby younger than 3 months with a rectal temperature of 100.4°F (38°C) or higher should receive prompt medical evaluation.

Dr. G's Pearl

Don't let the terminology make RSV prevention seem more complicated than it is. Think of it this way: Mom can make the antibodies and pass them to the baby during pregnancy, or we can give protective antibodies directly to the baby after birth. For most babies, one of those approaches is all that is needed.

Frequently Asked Questions

Is there an RSV vaccine for babies?

No RSV vaccine is currently given directly to infants. Babies can receive long-acting RSV antibodies called nirsevimab or clesrovimab.

What is the RSV shot for babies?

When parents refer to the “RSV shot,” they are usually talking about nirsevimab or clesrovimab. These are long-acting antibodies designed to reduce the risk of severe RSV disease.

What age do babies get the RSV shot?

RSV antibodies are recommended for eligible babies younger than 8 months who are born during or entering their first RSV season. Timing depends on when the baby is born, maternal RSV vaccination during the current pregnancy, local RSV seasonality, and the baby's medical circumstances.

Does my baby need the RSV shot if I received the RSV vaccine while pregnant?

Usually not. Most babies do not need both maternal RSV vaccination and an infant RSV antibody. One important exception is when the baby is born within 14 days after maternal vaccination. There are also uncommon medical situations in which an infant antibody may still be considered.

How long does the RSV antibody protect a baby?

CDC states that long-acting infant RSV antibodies provide protection for at least five months, which is intended to cover a typical RSV season.

Can my baby still get RSV after receiving the RSV antibody?

Yes. RSV immunization is intended primarily to reduce the risk of severe RSV disease and hospitalization. It does not guarantee that a baby will never become infected with RSV.

Can the RSV antibody be given with routine childhood vaccines?

Yes. Current CDC guidance allows infant RSV antibodies to be given during the same visit as routine childhood vaccines.

References

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Medical Disclaimer: This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. RSV immunization recommendations can vary based on a child's age, medical history, pregnancy history, geographic location, RSV seasonality, and evolving public health guidance. Always discuss your baby's individual needs with your pediatrician or other qualified healthcare professional.

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