I n May 2023, the U.S. Food and Drug Administration (FDA), approved two vaccines for preventing respiratory syncytial virus (RSV) in older adults: Arexvy (made by GSK) and Abrysvo (made by Pfizer).

In June 2023, following robust deliberation, the Center for Disease Control and Prevention (CDC)’s Advisory Committee on Immunization Practices (ACIP) voted to recommend that adults ages 60 years and older may receive a single dose of either the GSK or Pfizer RSV vaccine, using shared clinical decision-making. This means these individuals should talk to their healthcare provider about whether RSV vaccination is right for them.

The CDC director then endorsed ACIP’s recommendations, meaning it is now the official CDC public health guidance for safe use of the vaccine in the U.S.

“These vaccines — which are the first ones licensed in the U.S. to protect against RSV — are expected to be available ahead of this fall, providing an opportunity to help protect older adults against severe RSV illness at a time when multiple respiratory infections are likely to circulate,” says Michael Melgar, MD, medical officer with the CDC’s National Center for Immunization and Respiratory Diseases, based in Atlanta.

Here’s what you should know about these newly approved RSV vaccines.

RSV is a common respiratory infection that causes mild, cold-like symptoms that typically get better within a week or two. But, for some people, especially older adults, infants, and those with compromised immune systems, RSV can be serious — even deadly. “Each year, between 60,000 and 160,000 older adults in the United States are hospitalized [for RSV infection], and between 6,000 and 10,000 of them die from it,” says Dr. Melgar.

RSV vaccines are a monumental public health concern for older adults. The infection “is secondary to flu in terms of the number of older adults who are infected and sick with it [or] require hospitalization, and the number of deaths that occur,” says Edward Walsh, MD, a professor of infectious diseases in the department of medicine at the University of Rochester Medical Center in New York. “One of the key features of RSV is that the older you get, the more severe it can be.”

In 2022, the United States saw a high circulation of RSV, along with other respiratory viruses, as well as an increase in RSV detections, emergency department visits, and hospitalizations, which put significant stress on healthcare systems, says Melgar. “That recent activity helps underscore the importance and potential benefits of [vaccines] aimed at the prevention of severe RSV illness, particularly among at-risk populations,” he notes.

7 Essential Facts About the RSV Vaccine

2. The vaccines are similar, with minor differences.

Both vaccines are recombinant subunit vaccines, which means they contain specific pieces of the virus which prompt the immune system to produce antibodies against RSV.

One difference is that GSK’s vaccine includes an adjuvant, which is a component that is intended to boost the immune response to vaccination, while Pfizer’s does not. But, this doesn’t make one more effective than the other, according to Melgar. “Both are currently approved as a single dose and were shown to protect against lower respiratory tract disease caused by RSV in adults ages 60 and older, with more than 80 percent efficacy in the first RSV season after vaccination,” he says.

2. The vaccines are similar, with minor differences.

3. The vaccines aren’t for everyone.

Both RSV vaccines are approved only for adults 60 and over.

Dr. Walsh notes that older adults with underlying health conditions, such as lung disease, heart disease, or a weak immune system, are at particularly high risk for complications from RSV, such as hospitalization and death.

In addition, the older you are, the more you may benefit from the vaccine. “The benefit to a 60-year-old — unless they have some underlying disorders — is probably not that great compared to an 80-year-old,” says Walsh.

4. You won’t be protected from RSV immediately after you get vaccinated.

In the Abrysvo clinical trial, Walsh, who is the lead study author, says the effects of the vaccine could be seen at around 2 weeks, which is similar to the time frame for the COVID and flu vaccines. Arexvy is estimated to take about the same amount of time to become effective. “This is biologically plausible, because it takes about two weeks for a vaccine to induce a big boost in your antibodies in your blood,” Walsh says.

5. Even if you develop RSV after receiving the vaccine, it still offers benefits.

According to the FDA, the safety and effectiveness of Arexvy is based on a clinical trial of participants 60 and over. Among the participants who received the vaccine, the risk of developing RSV-related lower respiratory tract disease or severe RSV was reduced by more than 82 percent and 94 percent, respectively.

The Abrysvo clinical trial reported that the vaccine reduced the risk of developing RSV-related lower respiratory tract illness in participants by 86 percent.

5. Even if you develop RSV after receiving the vaccine, it still offers benefits.

6. Side effects seem to be relatively minor.

The RSV vaccine does come with a few side effects, but most are mild and similar to those associated with the flu and COVID-19 vaccines.

In the clinical study of Arexvy, some participants who received the vaccine reported muscle pain, joint stiffness, fatigue, headache, or pain at the injection site. Similar side effects were reported for Abrysvo.

In the Arexvy study, 10 participants developed atrial fibrillation within 30 days of vaccination, but it’s unclear whether it was related to the vaccine. GSK, the manufacturer of Arexvy, is doing more research to determine if there’s a link between the vaccine and the reported heart issue.

6. Side effects seem to be relatively minor.

7. We’re still learning about the need for booster shots.

Researchers aren’t yet sure if booster shots will be needed, given the vaccine has only been tracked for one full RSV season (fall 2021 through spring 2022). Data from fall 2022 through spring 2023 will be available in midsummer 2023. Researchers are looking to determine whether it provides equal protection in the second year, which would mean the vaccine has a longer effective period than what might be expected with the flu vaccine, which needs to be administered every winter, says Walsh.

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The ACIP and CDC did not make preferential recommendations between the two vaccines. “Both vaccines provide protection and are safe and effective,” says Melgar.

If you’re over 60, talk to your primary care doctor about whether an RSV vaccine makes sense for you. “Working with your primary care doc is always advisable in figuring out the best way to get caught up on all vaccines for which you are eligible,” says Jack O’Horo, MD, MPH, an infectious diseases specialist at Mayo Clinic in Rochester, Minnesota.

It’s also good to talk to your doctor about other vaccines you may want to get as an older adult, such as the flu, pneumonia, and shingles vaccines. “Talk to your healthcare provider about which vaccines are appropriate for you,” advises Melgar, “as it can differ based on age, health conditions, and vaccines received as a child, as well as other factors, including job, lifestyle, and travel.”

RSV Vaccine Rollout: What to Expect This Fall

The RSV vaccine is now available through your healthcare provider or local pharmacy. The CDC is also working alongside FDA and other federal agency partners to prepare for a fall vaccination campaign featuring RSV vaccines, as well as COVID-19 vaccines and annual flu vaccines.

Additionally, the CDC is working to share clear recommendations with the public to prevent serious illness from a variety of respiratory viruses, including COVID-19, RSV, and flu. These common preventive measures include:

Getting vaccinated against some of these viruses (COVID-19, flu, and RSV for adults 60 and older who decide with their provider that it’s right for them).
Practicing social distancing, covering coughs and sneezes, and washing hands frequently to help protect you and reduce the spread of respiratory viruses.
Following your doctor’s treatment advice if you do develop a respiratory illness to help prevent others from getting sick.

The Consumer’s Guide to RSV Vaccines for Older Adults