Should You Get an RSV Vaccine?

[Originally published: July 24, 2023. Updated: Aug. 29, 2025]

As fall and winter approach, and the coughing, sneezing, and fevers start up, it may be time to think about protection from an illness that makes many people very sick. Respiratory syncytial virus (RSV) is a highly contagious condition that causes mild cold symptoms in most people but can lead to hospitalization and death in older people and babies.

The good news is that there are effective immunizations to protect against RSV, and the Centers for Disease Control and Prevention (CDC) recommends them to certain groups. They include a choice of three RSV vaccines for all adults ages 74 and older, and those ages 50 to 74 who are at increased risk for severe RSV.

Two immunizations are available for babies, starting with a maternal RSV vaccine given to mothers during pregnancy that protects them after they’re born. If they don’t get that one, a newborn in their first eight months can have one of two monoclonal antibodies—laboratory-made proteins that provide protection.

“A lot has changed for RSV,” says Scott Roberts, MD, a Yale Medicine infectious diseases specialist. “There have been attempts to make a vaccine for decades, and they have failed for a variety of reasons.” A turning point came with a 2013 breakthrough that followed decades of research into a protein called “RSV fusion (F)” that provided potent stimulation to the immune system—research that paved the way to clinical trials showing positive results.

A decade later, in 2023, the Food and Drug Administration (FDA) approved the first two RSV vaccines for adults, the vaccine given in pregnancy, and the first monoclonal antibody. In 2025, the FDA approved two more options: a third vaccine choice for adults and another monoclonal antibody for infants.

RSV is a common respiratory virus that causes inflammation of the respiratory tract, usually leading to mild, cold-like symptoms, including nasal congestion and runny nose, sometimes with a low-grade fever. It’s a seasonal illness, typically starting in the fall and peaking in the winter. Once a person is infected, the treatment is supportive care, such as over-the-counter medications and maintaining hydration. Most people get better in a week or two.

The vaccines for older people are important, partly because immunity wanes with age, making it more difficult to fight off infections such as RSV as easily as they did when they were younger, explains Dr. Roberts.

But when RSV makes its way down into the lungs, causing lower respiratory tract disease (LRTD), it can cause vulnerable people to develop life-threatening complications, such as pneumonia, and worsen existing conditions, such as asthma, congestive heart failure, and chronic obstructive pulmonary disease (COPD). You are at higher risk for severe illness from RSV if you are 65 or older or have a weakened immune system or a chronic medical condition such as heart or lung disease.

Infants are susceptible to RSV because their immune systems are not fully formed, adds Thomas Murray, MD, PhD, a Yale Medicine pediatric infectious diseases specialist. “Their lungs aren't fully developed. So, if the virus gets into the lungs of really young babies, they can develop respiratory problems and need support, such as supplemental oxygen, to help them breathe.” In fact, two out of three babies will get RSV by the time they are a year old.

Each year, this leads to up to 80,000 hospitalizations in children younger than 5 years and up to 180,000 in adults ages 50 years and older. RSV has caused up to 300 deaths in a year in children, and up to 10,000 in adults 65 years and older.

• Adults ages 60 and older: The three RSV vaccines include Abrysvo® from Pfizer; Arexvy® from GSK; and mResvia®, from Moderna. Each is given in a single injection in the upper arm, much like the flu shot. Eligible adults may choose to get any one of them. While these vaccines are available anytime, the best time to get them is late summer and early fall.
• Pregnant women who want to protect newborn babies: Abrysvo may be given ahead of the RSV season to provide antibodies that could be passed along to the fetus to protect newborns from birth to 6 months of age from severe RSV. It’s recommended during weeks 32 to 36 of pregnancy. The shot is available from September through January to provide protection to newborns when infection rates are expected to be at their highest, between October and March.
• Infants: Two monoclonal antibody immunizations are recommended for newborns up to 8 months old whose mothers did not get the Abrysvo vaccine. Nirsevimab (Beyfortus®) and clesrovimab (Elflonsia™) protect infants for at least five months after birth, when they are most at risk—nirsevimab is also available to a small group of children ages 8 to 19 months who are also at high risk of severe disease. Both are given by injection, usually in the thigh, and are available October through March.

All of the RSV shots are highly effective. Abrysvo and Arexvy have been shown to be around 80% effective in studies conducted in real-world settings (beyond the initial clinical trials) at preventing RSV-related hospital emergency department encounters. Moderna’s mResvia is more recent and a comparable real-world estimate isn’t available yet, but clinical trials showed it to have approximately 80% efficacy after the first four months after vaccination.

Both the Arexvy and Abrysvo vaccines for older adults use traditional platforms—also like the traditional flu shot. They work by introducing an inactivated RSV fusion (F) protein into the body, where it fuses to host cells and stimulates the immune system to recognize the actual RSV virus if and when it encounters it, helping to prevent severe disease.

The mResvia shot uses an mRNA platform like the COVID vaccines made by the Moderna and Pfizer-BioNTech companies. The relatively new mRNA technology is a way of sending instructions to host cells in the body for making copies of a specific RSV protein. That protein will then trigger the immune system to produce neutralizing antibodies that will be able to recognize and attack the actual virus.

The Abrysvo vaccine given during pregnancy is also highly effective for newborns. In clinical trials, it reduced the risk of hospitalization in the first three months by 68% and in the first six months by 57%.

The two monoclonal antibodies for very young children work differently than the vaccines. “When you're injected with a vaccine, it causes your body to produce antibodies to protect you against whatever the vaccine is for,” Dr. Murray says. “The monoclonal antibody bypasses that step. Your body gets—in this case—a single kind of antibody directly injected into the bloodstream so that if you're infected with that organism, the antibodies will bind to it and help you clear the infection.”

The monoclonal antibodies reduce hospitalization significantly, Dr. Murray says. "Even if they don’t completely prevent disease, they can significantly reduce disease severity,” he says. Real world studies of nirsevimab have confirmed that it can reduce RSV disease by 87% in healthy term infants and lower hospitalizations by 98%. A Yale School of Medicine study showed that timing the shot to coincide with seasonal outbreaks is crucial to its effectiveness.

While it’s too early to know how well clesrovimab is working in the real world, it showed an 84.3% reduction in RSV-associated hospitalizations through five months.

If you don’t fall into one of those categories and are otherwise healthy, you probably don’t need a preventive therapy, Dr. Murray explains. “Virtually every child has experienced RSV by the age of 2 and has immunity,” he says.

Likewise, older children, teenagers, and most adults have strong immunity from multiple exposures to the virus and rarely experience LRTD from RSV.

There may be mild side effects, such as pain, redness, and swelling where a shot was given. Fatigue, fever, headache, nausea, diarrhea, and muscle or joint pain may occur. People who have experienced these symptoms when getting other vaccines might be more likely to experience them after getting an RSV vaccine.

The FDA requires warning labels on the Abrysvo and Arexvy vaccines to inform people about a slightly increased risk for Guillain-Barré Syndrome (GBS) in the 42 days after vaccination. GBS is a rare disorder that affects an estimated 3,000 to 6,000 people a year in the U.S., causing muscle weakness and sometimes paralysis. While the agency noted that available evidence is insufficient to show a causal relationship between the RSV vaccines and the disorder, it made the warning in early 2025 based on its evaluation of data from clinical trials, reports to the government’s Vaccine Adverse Event Reporting System (VAERS), and a post-marketing study.

There is no warning about GBS on Moderna's mResvia vaccine. mResvia’s most common side effects included injection site pain, fatigue, headache, and muscle pain.

In addition, atrial fibrillation (an arrhythmia that can lead to blood clots in the heart) within 30 days of vaccination was reported in 10 clinical trial participants who received AREXVY and four participants who received a placebo.

“One could argue that the benefits of these vaccines far outweigh the risks,” says Dr. Roberts. “For instance, the protection afforded against severe RSV disease is greater than the small risk of Guillain-Barré in this situation.”

The CDC recommends that all adults ages 75 and older and those ages 60 to 74 who have risk factors for severe RSV disease, such as chronic heart or lung disease, a weakened immune system, other medical conditions such as diabetes, and/or live in a nursing home, get one of the three RSV vaccines. The CDC provides a list of conditions that increase the risk of severe disease from RSV.

The CDC recommends August to October as the best time in most of the continental U.S. to get the shot before the RSV season.

The RSV vaccine is not given annually at this time, since protection from the RSV vaccine lasts more than a year, according to the CDC. The agency says it may update its recommendation as more information about the three vaccines for older adults becomes available.

Both Drs. Roberts and Murray also suggest that people who are vulnerable or could infect others who are at high risk take additional precautions in the fall and winter, when RSV is likely to circulate. RSV is spread through direct contact with the virus, whether that's from droplets from another person's cough of sneeze, or from touching a contaminated surface.

In addition, the CDC recommends covering coughs and sneezes with a tissue or shirt sleeve (not your hands), washing hands often, keeping hands away from your face, avoiding kissing and other close contact with people who have cold-like symptoms, cleaning frequently touched surfaces, such as doorknobs and mobile devices, and staying home when you are sick. Some experts advise wearing a mask depending on your risk for serious disease.

“All of these things will protect against RSV,” Dr. Roberts says.