RSV (Respiratory Syncytial Virus) Vaccines

Medically Reviewed by Neha Pathak, MD on May 22, 2024
Written by Kristen Fischer
10 min read

An RSV vaccine is a shot that protects you from respiratory syncytial virus (RSV), which infects your lungs and respiratory tract. Most cases of RSV are mild, but they can be serious in children, older adults, and people with immune system problems as well as heart and lung issues. If you’re pregnant and get RSV, it can cause complications for you and your baby. 

There’s no specific treatment for RSV. Two vaccines for RSV came on the market in 2023 with the goal of preventing infections and serious complications. The RSV vaccines can prevent lower respiratory tract disease (LRTD) caused by RSV. One of the vaccines is only for pregnant people. But both are approved for older adults. A monoclonal antibody treatment for infants and toddlers is also available, but it’s technically not a vaccine.

Like a cold, RSV is spread through the air and direct contact. If someone sneezes near you, shakes your hand, or you touch a contaminated surface, you can pick up RSV. Once infected, you are most contagious during the first week or so. In infants and those with weakened immune systems, the virus can spread for up to 4 weeks, even after symptoms are gone.

RSV vaccine name

There are two RSV vaccines to prevent the virus. They are:

Abrysvo. The FDA approved Abrysvo for pregnant people to prevent RSV in infants from birth through 6 months of age. Expectant parents can get a single-dose shot of Abrysvo from 32 weeks through 36 weeks of pregnancy. It’l protect you and the infant. 

Arexvy. This vaccine is for older adults. People over the age of 60 have the choice to take either Abrysvo and Arexvy. They are both single-dose RSV shots.

There’s not an actual RSV vaccine for children, but there is a treatment that can protect them from the virus. The shot is a monoclonal antibody called nirsevimab (Beyfortus). The treatment is made of antibodies to the RSV virus. It’s different from a vaccine because a vaccine helps your immune system build antibodies to the virus in case it infects you. Both methods help fight the virus. Beyfortus is only for children.

Is the RSV vaccine a live vaccine?

The vaccines aren’t live vaccines. This means they don’t contain a part of the RSV virus itself. So you’re not injecting the actual virus into your body. The RSV shots don’t cause you to get the infection.

The RSV vaccine consists of inactivated RSV proteins. Once you get the shot, the inactivated protein signals your immune system to recognize the actual virus if it were to enter into your body. This alarm system can help your body fight off the RSV virus and prevent severe cases of it.

RSV vaccines don’t include mRNA technology like the Pfizer and BioNtech COVID-19 vaccines do. The RSV vaccines use traditional technology, like a flu shot.

How is the RSV vaccine made?

Both RSV vaccines include a single surface protein of the virus known as protein F. When the vaccines are made, the gene for protein F is added to cells. As the cell grows, so does the protein. Technicians then harness the protein to include it in the vaccines.

Abrysvo contains the F protein from both types. It doesn’t contain an adjuvant, which is something added to the formula that aims to allow your immune system to respond better to the vaccine. Arexvy only contains a single F protein. Arexvy contains an adjuvant (which makes the treatment work better); the same one in the GSK shingles vaccine. 

Both RSV vaccines are slightly different, but the CDC doesn’t prefer one over the other.

How is the RSV monoclonal antibody made?

The monoclonal antibody, Beyfortus, is different because it doesn’t help infants make antibodies—it introduces the antibody into them directly.

The antibody attaches on to the F protein in RSV, which prevents the virus from attaching to other cells and entering them. The antibody is called immunoglobulin G (IgG), and it’s common in our blood. 

In the lab, the gene for the antibody is added to cells. When the cells reproduce, they make more of the antibodies. Then the antibodies are purified to form the monoclonal antibody injection.

People over the age of 60 should talk to their doctor to see if they should get the RSV vaccine. They may suggest it especially if you have a weakened immune system from another condition or from medications you take, have another chronic illness, or if you live in a nursing home.

You shouldn’t get the RSV vaccine if you’ve ever had an allergic reaction to any of the vaccines’ ingredients.

When will the RSV vaccine be available to everybody?

It’s unclear when the existing RSV vaccines may be rolled out to people in other age groups. 

During the 2023-2024 RSV season in the U.S., there were limited supplies and documented shortages of the vaccine. Not all older adults and expectant parents could receive one. Other RSV vaccine options are in the works.

If you’re an older adult or are pregnant, there are different recommendations for RSV vaccines.

RSV vaccine for adults

As of now, RSV vaccines are only approved for adults over 60 and pregnant people. If you’re in another age group, you likely don’t need the vaccine because you’ve probably had RSV and are immune to it. Pfizer has studied Abrysvo in adults 18 to 59 years old, but it’s not yet approved for that age group. GSK is in the process of getting Arexvy approved for people 50 to 59 who are at high risk.

RSV vaccine for seniors

Adults 60 and older can get a single dose of either RSV vaccine. The CDC advises getting the vaccine during the late summer or early fall, which is before RSV tends to spread more. 

During the vaccine approval process, the CDC was concerned about clinical trial data. As a result, the CDC changed the wording from recommending the vaccine to suggesting that people talk to their doctors about getting it. The new wording states that older adults may get the vaccine.

According to the CDC, you can get an RSV vaccine along with your flu and COVID-19 shots. If you want to get them separately, there’s no minimum waiting period between injections.

RSV vaccine for babies and children

Technically, there’s no RSV vaccine for babies and children. If you’re pregnant, you can get Abrysvo between 32 and 36 weeks from September through January (known as RSV season). The antibodies your body makes will pass from you to your baby to protect it upon birth.

If you don’t get the vaccine but still want to protect your infant from RSV, your baby can get Beyfortus. Like the traditional RSV vaccines for adults, both methods help fight the virus. 

The CDC recommends all infants 8 months and younger who are born during or entering their first RSV season get a single dose of the RSV monoclonal antibody treatment. Children who are between 8 months and 19 months old who have an increased risk for severe RSV (and entering their second RSV season) should also get the treatment, the CDC recommends.

Most babies won’t need the monoclonal antibody treatment in order to be protected if their pregnant parent is vaccinated, the CDC says.

RSV vaccine and pregnancy 

Pregnant people are more at risk for complications from RSV. It can pass to your infant while you’re still pregnant. The FDA approved a vaccine for expectant parents in 2023.

Pregnant people can get a single dose of the RSV vaccine known as Abrysvo. The second RSV vaccine (Arexvy) isn’t approved for use if you’re expecting.

You could have a higher risk for severe RSV while pregnant if you have a preexisting lung disease like asthma. Severe RSV can cause life-threatening complications such as pneumonia and or sepsis.

Another complication from having RSV that’s also tied to the vaccine is preterm birth. Arexvy was linked to preterm birth during clinical trials, which were stopped early. During clinical trials of Abrysvo, people who were pregnant got the RSV vaccine between weeks 24 and 36 of their pregnancies. More preterm births were reported in those who got the vaccine compared to those who didn’t, but the CDC noted it wasn’t statistically significant. 

As a result, the FDA recommends getting Abrysvo during weeks 32 and 36 of your pregnancy in order to reduce the risk of preterm delivery. Researchers studying Abrysvo didn’t study it on high-risk pregnancies. 

Pregnant people can have side effects from the RSV vaccine such as pain, swelling, or redness where the needle went in the skin. Headache, nausea, muscle and joint pain, fatigue, and fever are some of the mild side effects. Serious side effects, including Guillain-Barré syndrome (GBS) and other inflammatory neurologic events, were reported after some people got RSV shots during clinical trials.

RSV monoclonal antibody for infants

Beyfortus is for babies under 8 months old who are born during RSV season or going into their first RSV season. The treatment isn’t a vaccine. Once it’s out of the child’s body, they don’t have protection against RSV.

Children who are between 8 months and 19 months old who have an increased risk for severe RSV (and entering their second RSV season) should also get the treatment, the CDC recommends.

A different monoclonal antibody, palivizumab, is used for children 24 months and younger with certain conditions that place them at high risk for severe cases of RSV. It must be given once a month during RSV season.

If you use Medicare, you should be able to get the RSV shot covered at your doctor’s office or a pharmacy. Medicare Advantage Plan users should contact their plan provider to find out the nearest RSV vaccine location.

If you use another insurance plan or don’t have insurance, check with your local pharmacy, doctor’s office, or hospital. 

Most insurers cover the cost for the RSV vaccine because the CDC’s Advisory Committee on Immunization Practices approved them. Check that your provider is in network because some providers charge a fee to get the shot.

Medicare Part D covers the vaccine costs for those users.

According to the CDC, the cost for Arexvy at the time this was published was about $175, while Abrysvo was about $195. Other estimates say the shots run anywhere from $180 and $295 without insurance.

Does Medicare cover RSV vaccines?

Medicare drug coverage (Part D) covers the RSV shot. Part A and Part B don’t cover the vaccine. 

The RSV vaccine may have some side effects, but not in everyone who gets it. 

Common side effects 

According to the CDC, the most common side effects from the RSV vaccine were:

  • Pain
  • Redness
  • Swelling where the needle goes in
  • Headache
  • Nausea
  • Diarrhea
  • Muscle/joint pain
  • Fatigue
  • Fever

Sore arm, fatigue, headache, and muscle or joint pain were most common in older adults.

Pain where the needle went in, headache, muscle pain, and nausea were the most common side effects in pregnant people.

Reactions to RSV vaccine 

Some people have soreness, redness, or swelling at the spot on your arm where the needle goes in.

Serious side effects 

Serious adverse effects, including Guillain-Barré syndrome (GBS) and other inflammatory neurologic events, were reported after some people got RSV shots during clinical trials. Some people reported atrial fibrillation (irregular heartbeat that can lead to blood clots in the heart).

Atrial fibrillation within 30 days of vaccination was reported in 10 people who received Arexvy and four people who received a placebo.

Most of the people in the clinical trials were in their 60s, so there wasn’t a lot of data on other high-risk groups like those over the age of 80. 

In initial clinical trials, GSK, the company that makes Arexvy, reported that it was 82.6% effective against lower respiratory tract disease during the first season, 77.3% effective during the middle of the season, and 67.2% effective over two seasons. The shot was 94.1% effective against severe RSV during the first season, 84.6% effective at the middle of the season, and 78.8% effective over two seasons.

Pfizer’s Abrysvo vaccine was nearly 89% effective against LRTD in cases with at least three symptoms during the first year after vaccination. Midway through the second season, it was 78.6% effective.

How long does the RSV vaccine last?

One shot could offer some protection for at least two RSV seasons, but there’s been no official word on how often people should get shots. 

If you’re an older adult or you’re pregnant, you can get an RSV vaccine to protect yourself or your unborn child from RSV. Older adults can get either Arexvy or Abrysvo, but pregnant people can only get Abrysvo. There’s an RSV antibody treatment for babies and toddlers called Beyfortus, but technically it's not a vaccine.

Does the CDC recommend the RSV vaccine?

The CDC recommends that older adults have the option to get Arexvy or Abrysvo. The CDC recommends pregnant people get Abrysvo between 32 weeks and 36 weeks.

What vaccines are candidates for RSV?

At the time of this writing, Moderna’s RSV vaccine was waiting for FDA approval. If approved, it would be the first mRNA vaccine approved for RSV. This differs from traditional vaccines because mRNA tells the cells to make the viral protein, which drives the body to make antibodies against it. Both manufacturers of the existing two RSV vaccines are trying to get their products approved for younger people.

What’s the RSV season?

In the U.S., RSV season is a period of time each year from fall through spring when RSV activity is higher. 

What are the downsides of the RSV vaccine?

All vaccines can come with side effects, though some people don’t experience side effects at all. The RSV vaccines were released in 2023, and scientists will be studying the effects of its rollout as time goes on.

Should I get the RSV vaccine now?

If you’re pregnant or over the age of 60 and RSV season is coming up, talk to your doctor or health care professional to see if you should get the shot.

Who shouldn’t get the RSV vaccine?

The RSV vaccine is only approved for people who are pregnant or over the age of 60. If you’re in another age group, you likely don’t need the vaccine because you’ve probably had RSV and are immune to it.