Respiratory syncytial virus (RSV) is a frequent cause of respiratory illness. Every year RSV causes significant rates of morbidity and mortality in older adults, including lower respiratory tract disease (LRTD), hospitalization, and death – causing an estimated 60,000–160,000 hospitalizations and 6,000–10,000 deaths annually among adults aged ≥65 years.
In May 2023, the Food and Drug Administration (FDA) approved the first RSV vaccines for adults aged ≥60 years.
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For the prevention of RSV-associated LRTD there is:
- Arexvy, by GSK, a 1-dose adjuvanted recombinant stabilized prefusion F protein (preF) vaccine
- Abrysvo, by Pfizer, a 1-dose recombinant stabilized preF vaccine
What's the evidence?
There is one randomized controlled trial for each vaccine.
GSK Vaccine
There is one ongoing randomized, double-blind, placebo-controlled phase 3 clinical trial conducted in 17 countries and including 24,973 immunocompetent participants aged ≥60 years randomized 1:1 to receive 1 dose of vaccine or saline placebo.
Data was collected during May 2021–March 2023, which included two complete RSV seasons for Northern Hemisphere participants and one complete RSV season for Southern Hemisphere participants.
The follow up period from time of vaccination to end of follow-up was approximately 15 months per participant.
The efficacy of one dose of the GSK vaccine in preventing symptomatic, laboratory-confirmed RSV-associated LRTD was 82.6% (96.95% CI = 57.9%–94.1%) during the first RSV season and 56.1% (95% CI = 28.2%–74.4%) during the second season.
Efficacy of 1 dose over two seasons was 74.5% (97.5% CI = 60.0%–84.5%) in preventing RSV-associated LRTD and 77.5% (95% CI = 57.9%–89.0%) in preventing medically attended RSV-associated LRTD.
The study was not powered to estimate efficacy against hospitalization (intervention group = one event; control group = five events), severe RSV illness requiring respiratory support (intervention group = one event; control group = five events), or death (no events).
Pfizer Vaccine
There is one ongoing, randomized, double-blind, placebo-controlled phase 3 clinical trial conducted in seven countries and including 36,862 immunocompetent participants aged ≥60 years randomized 1:1 to receive 1 dose of vaccine or placebo containing the same buffer ingredients as the vaccine but without active components.
Data was collected during August 2021–January 2023, which included one complete RSV season for Northern and Southern Hemisphere participants and a partial second season for Northern Hemisphere participants only.
The average follow-up time from vaccination to end of efficacy follow-up was approximately 12 months per participant.
Efficacy of 1 dose of the Pfizer vaccine in preventing symptomatic, laboratory-confirmed RSV-associated LRTD was 88.9% (95% CI = 53.6%–98.7%) during the first RSV season and 78.6% (95% CI = 23.2%–96.1%) during the partial second season.
Efficacy of a single dose over two seasons was 84.4% (95% CI = 59.6%–95.2%) in preventing RSV-associated LRTD and 81.0% (95% CI = 43.5%–95.2%) in preventing medically attended RSV-associated LRTD.
The study was not powered to estimate efficacy against hospitalization (intervention group = one event; control group = three events), severe RSV illness requiring respiratory support (intervention group = one event; control group = one event), or death (no events).
CDC/ ACIP Recommendation
For RSV vaccination, the decision to vaccinate a patient should be based on a shared decision making and discussion.
Adults ≥60 years who are at the highest risk for severe RSV disease and who might be most likely to benefit from vaccination include those with chronic medical conditions such as chronic obstructive pulmonary disease, asthma, congestive heart failure, coronary artery disease, cerebrovascular disease, diabetes mellitus, and chronic kidney disease, hematopoietic stem cell transplantation and patients taking immunosuppressive medications (e.g., for solid organ transplantation, cancer treatment, or other conditions).
Others who may be at higher risk of RSV infection include residents of long-term care facilities, and persons who are frail, or above age 75 years.
RSV Vaccine Timing
There is not enough evidence to determine optimal timing or the need for revaccination.
It is acceptable to have the RSV vaccine administered at the same time as with other adult vaccines during the same visit.