Can an RSV Vaccine Protect Infants From the Virus?

Respiratory syncytial virus (RSV) typically sends more than 2.1 million young children to U.S. healthcare centers every year. The illness is the most common cause of hospitalization for infants before their first birthday, too.

And at its worst, RSV can be deadly, as hundreds of families with young children learn after the virus starts circulating every fall.

That’s why protecting little ones from RSV is so important. Thankfully, an RSV immunization for babies debuted in 2023 with encouraging results. For more on this breakthrough, we turn to pediatric infectious disease specialist Frank Esper, MD, and pediatrician Kristin Barrett, MD.

How effective is RSV immunization?

RSV immunization was 90% effective at preventing hospitalization for infants going through their first season of exposure to the respiratory virus, according to the U.S. Centers for Disease Control and Prevention (CDC).

The CDC study looked at data from its New Vaccine Surveillance Network. The review followed federal approval of the RSV immunization medication known as nirsevimab (brand name Beyfortus®).

“We saw a huge reduction in needed medical attention for babies who got the injection compared to those who did not,” shares Dr. Barrett.

Why is RSV immunization important?

Babies who get RSV can become very ill, sometimes, needing to be hospitalized to receive breathing treatments. Infants under 6 months old are at particularly high risk for severe RSV infection.

The infection can lead to lung issues such as bronchiolitis or pneumonia.

“RSV can cause a lot of swelling in your airways,” explains Dr. Esper. “Babies’ windpipes are small to begin with, so it doesn’t take a lot of swelling to close them shut.”

Children born preterm or those who have certain heart issues are also more vulnerable to RSV.

“No one wants to see babies getting sick if we can prevent it,” he continues. “These RSV immunizations give healthcare providers and parents some peace of mind knowing that we can protect infants from what can be a very dangerous infection.”

At what age should children get an RSV shot?

The CDC recommends an RSV immunization for infants younger than 8 months who are entering their first fall-to-spring RSV season or born during it. (Babies whose birth parent received an RSV vaccine during pregnancy do not need an immunization.)

In some cases, a follow-up immunization is suggested for children between 8 months and 19 months of age entering their second RSV season. Candidates are usually considered at high risk for RSV complications given other health issues.

The CDC doesn’t recommend RSV immunization for any child aged 20 months or older. By that age, most kids have been exposed to RSV and their immune system has built up antibodies.

“Parents know just how much kids grow and change in their first year,” says Dr. Esper. “The same is true for their immune systems. It’s evolving and working better every day. It’s amazing what a 1-year-old’s immune system can do for them compared to the first days of their life.”

Older children and their more developed respiratory systems also are better able to tolerate the symptoms of RSV. They may still get uncomfortable (and cranky) with the virus, of course, but they’re less likely to reach a dire health status.

Is RSV immunization safe for kids?

An “owie” from the shot is the main side effect of an RSV immunization.

“There could be redness, pain or maybe a little bit of swelling or rash at the injection site,” says Dr. Barrett. “And those minor side effects occurred in less than 1% of the babies who had the immunization.”

Is an immunization different than a vaccine?

Strictly speaking, nirsevimab — the RSV prevention method for babies — isn’t a vaccine. It’s an immunization. And the difference between the two is more than semantics.

When you get a vaccine, what you’re receiving is a teeny part of a deactivated virus. That virus spurs your immune system to create antibodies — proteins that hunt down and remove the virus from your body.

The RSV immunization, on the other hand, doesn’t use the RSV virus at all. Instead, it’s an injection of synthetically produced antibodies that are ready and raring to fight off RSV. It gives infants a ready-made defense system against the virus.

“The antibodies give babies almost instant protection,” says Dr. Barrett. “It’s enough to lower the risk of a serious infection during their first RSV season, which is when the virus is most dangerous for them.”

Abrysvo®, the form of RSV prevention available during pregnancy, is a true vaccine — so it delivers a bit of deactivated virus into the person who is pregnant. It’s offered between 32 weeks and 36 weeks of pregnancy.

The vaccine prompts the birth parent to create antibodies to fight off the virus. Those RSV antibodies are then passed along to the developing fetus. As a result, your baby is born with some protection against severe RSV infection.

The same vaccine is recommended for adults aged 75 and older, plus adults between 60 and 74 with certain chronic conditions.

Other ways to protect babies from RSV

Immunization is one important part of what should be a multipronged approach to keeping your baby healthy during RSV season. Dr. Barrett and Dr. Esper also suggest infection-control strategies like:

• Washing your hands regularly with soap and water. (And encouraging anyone who’s going to touch or hold your baby to scrub up, too.)
• Covering your cough, given how easily RSV spreads.
• Not allowing people who are sick to be around your baby.
• Keeping your baby home if they’re showing signs of being sick, like a runny nose or cough.

Immunizing babies and taking other precautionary steps may help protect others who are more at risk from RSV. Aside from young children, adults over the age of 60 and people who are immunocompromised are also more susceptible to RSV and complications from the virus.

“What we’ve seen with other vaccines is that when we vaccinate our children, other people around them are less likely to get infected,” notes Dr. Esper. “So, by immunizing a baby, that may mean less illness for parents, siblings, grandparents and others who are around the baby.”

Final thoughts

If you have an infant, Dr. Barrett and Dr. Esper urge you to consider getting them immunized against RSV to protect their health.

“We know that immunizing kids against infectious disease makes children healthier,” Dr. Esper says. “The RSV immunization is a huge win for the infants of the United States and around the world.”

So, take advantage of it.