Ask the Experts: RSV (Respiratory Syncytial Virus): Vaccine Products

Results (7)

In May 2023, FDA licensed two RSV vaccines: RSVPreF3 (Arexvy, GSK) and RSVpreF (Abrysvo, Pfizer). A third RSV vaccine, mRNA RSV (mResvia, Moderna), was licensed by FDA in May 2024. All three vaccines are licensed for the prevention of RSV-associated lower respiratory tract disease (LRTD) in adults 60 age years and older in the United States. Arexvy is also licensed for use in adults age 50 through 59 years who are increased risk of RSV LRTD; however, ACIP has not yet made recommendations for its use in this age group. Only Abrysvo is licensed for use during pregnancy (during 32 through 36 weeks and 6 days’ gestation) for the prevention of RSV disease in infants.

Arexvy and Abrysvo are recombinant protein vaccines that contain the prefusion form of the spike protein found on the surface of the RSV virus. The mResvia mRNA vaccine contains mRNA that encodes the prefusion form of the RSV F glycoprotein. The mRNA vaccine temporarily enables some of the vaccine recipient’s own cells to produce the prefusion form of the spike protein, causing the immune system to respond by generating antibodies to it. Because none of these vaccines contain live virus, they cannot cause RSV illness.

The GSK vaccine, Arexvy, includes an AS01adjuvant, a chemical designed to enhance the immune response to vaccination. AS01 is the same adjuvant used in GSK’s recombinant zoster vaccine (Shingrix), but Arexvy contains half the amount of adjuvant as a dose of Shingrix. Abrysvo and mResvia vaccines do not contain an adjuvant.

For further information about the vaccines, see the FDA package inserts: Arexvy (www.fda.gov/media/167805/download); Abrysvo (www.fda.gov/media/168889/download); and mResvia (www.fda.gov/media/179005/download).

Last reviewed: August 25, 2024

All three RSV vaccines were effective in preventing RSV-associated lower respiratory tract disease (LRTD) in clinical trial participants, over the course of two RSV seasons.

The global clinical trials for RSVPreF3 (Arexvy, GSK) vaccine involved nearly 25,000 participants and some participants were followed for 2 RSV seasons. One dose reduced the risk of laboratory-confirmed RSV-associated LRTD with two or more symptoms by 82.6% during the first RSV season and 56.1% during the second season.

The RSVpreF (Abrysvo, Pfizer) vaccine global clinical trials involved nearly 37,000 participants, and some participants were followed for 2 RSV seasons. One dose reduced the risk of symptomatic, laboratory-confirmed RSV-associated LRTD with 3 or more symptoms by 88.9% during the first RSV season and 78.6% during a partial second season.

The mRNA RSV (mResvia, Moderna) vaccine global clinical trials involved nearly 37,000 participants. One dose reduced the risk of symptomatic laboratory-confirmed RSV LRTD with three or more symptoms by 80.9% in the first season. After a median follow up time of 18.8 months, its efficacy declined to 48.4%.

Few people enrolled in the clinical trials were either frail or of advanced age (80 or older), and none lived in long-term care facilities. People with immunocompromising conditions were excluded from clinical trials. For this reason, the clinical trials did not measure how well the vaccines would work in the people at highest risk of serious RSV disease.

Last reviewed: August 25, 2024

Yes. Several studies have measured the effect of vaccination on preventing RSV-associated hospitalizations among people vaccinated in the first RSV season after the recommendation for use of the vaccine. Estimates were similar for both the GSK and Pfizer products and showed that they reduced the risk of hospitalization among recipients overall by between 75% and 82%. For additional details, see the CDC MMWR published in August 2024: www.cdc.gov/mmwr/volumes/73/wr/pdfs/mm7332e1-H.pdf.

Last reviewed: August 25, 2024

Currently, protection from serious lower respiratory tract disease (LRTD) after RSV vaccination is expected to last for about two RSV seasons, but exactly how well it protects over a longer period of time is not yet known. In clinical trials, the ability of the vaccine to reduce the risk of serious lower respiratory tract disease was tested in some people over 2 RSV seasons, and all RSV vaccines provided meaningful protection in the second season.

RSV vaccination is currently recommended as a single dose: revaccination is not yet recommended. ACIP will update its recommendations concerning whether to revaccinate, and when, as more data become available over time concerning how long protection from a single dose lasts and how effective revaccination is in boosting protection. A small study by GSK did not show a meaningful benefit of revaccination with Arexvy just one year after dose 1; however, revaccinating after two or three years, or longer, might be helpful. Studies are underway to evaluate the benefit of revaccination at different intervals.

Last reviewed: August 25, 2024

All three RSV vaccines are currently licensed and recommended as a one-time dose for any person. Data are not available at this time to make recommendations for revaccination. At this time, a pregnant person who receives Abrysvo (Pfizer) during one pregnancy is not recommended to receive Abrysvo during a subsequent pregnancy: in subsequent pregnancies, the baby should receive nirsevimab (Beyfortus, Sanofi) after delivery for RSV protection. ACIP will make decisions concerning RSV revaccination as more data become available over time.

Last reviewed: August 25, 2024

Only the RSVpreF vaccine, Abrysvo by Pfizer, is licensed and recommended for one-time use between 32 weeks and 36 weeks 6 days of gestation to prevent RSV-associated lower respiratory tract disease in infants younger than 6 months old. Do not use Arexvy (GSK) or mResvia (Moderna) during pregnancy. If a pregnant person received an RSV vaccine before the current pregnancy, do not use Abrysvo during this pregnancy. Instead, counsel them that a dose of nirsevimab (Beyfortus, Sanofi) will be needed to protect the infant from RSV after birth.

Last reviewed: August 25, 2024

Both protein-based RSV vaccines (Abrysvo, Pfizer; Arexvy, GSK) are stored in the refrigerator. RSVpreF (Abrysvo) is supplied in a kit that includes a vial of lyophilized antigen component (a white powder), a prefilled syringe with a sterile water diluent, and a vial adapter. Store at refrigerated temperatures between 2°C and 8°C (36°F and 46°F) in the original carton. Do not freeze. Discard if frozen. Follow reconstitution guidelines at www.fda.gov/media/168889/download.

After reconstitution, administer immediately or store at room temperature (defined for this vaccine as 15ºC to 30ºC [59°F to 86°F]) for up to 4 hours. Do not store reconstituted Abrysvo vaccine in the refrigerator or freezer. Discard reconstituted vaccine if not used within 4 hours.

Last reviewed: August 25, 2024

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