Lauren Howell, PharmD
Since May 2023, FDA has approved two respiratory syncytial virus (RSV) vaccines; the first time a vaccine for RSV has been approved for use in the United States. According to CDC, RSV leads to approximately 60,000 to 120,000 hospitalizations and 6,000 to 10,000 deaths among adults 65 years and older each year in the United States.
Both Arexvy (GSK) and Abrysvo (Pfizer) were approved for the prevention of lower respiratory tract disease caused by RSV in individuals 60 years and older. They are both injected intramuscularly as a single 0.5 mL dose. The most commonly reported adverse reactions for both vaccines.were injection site pain, fatigue, myalgia, headache, and arthralgia
Clinical trials for Arexvy
The efficacy of Arexvy against RSV-associated lower respiratory tract disease in adults 60 years and older was evaluated in an ongoing, Phase 3, randomized, placebo-controlled, observer-blind clinical study conducted in 17 countries. While immunocompromised participants were excluded from the study, participants with pre-existing, chronic, stable disease were allowed to participate in the study if deemed medically stable at the time of vaccination. The 24,960 participants were randomized equally to either receive one dose of Arexvy or placebo. Study authors plan to follow participants for up to 36 months but at the time of primary efficacy analysis, they had been followed for up to 10 months.
Compared with placebo, Arexvy significantly reduced the risk of developing RSV-associated lower respiratory tract disease by 82.6% in participants 60 years and older. In participants 70 years and older, the risk was reduced by 84.4%. Additionally, Arexvy reduced the risk of developing severe RSV-associated lower respiratory tract infections by 94.1%. The median duration of efficacy follow-up was 6.7 months.
Clinical trials for Abrysvo
The efficacy of Abrysvo in individuals 60 years and older was evaluated in an ongoing, Phase 3, multicenter, randomized, double-blind, placebo-controlled study. Study authors plan to follow patients for up to two RSV seasons, approximately 25 months. Randomization was stratified by age: 60 to 69 years, 70 to 79 years, and those 80 years and older. Healthy adults and adults with stable chronic diseases were included. Out of the enrolled participants, 15% had stable chronic cardiopulmonary conditions. Beginning 14 days after vaccination, participants were monitored for onset of acute respiratory illness symptoms. The median duration of follow-up for efficacy was 7 months.
The study split episodes of RSV-associated lower respiratory tract disease into two groups, those with two or more symptoms and those with three or more symptoms. Researchers observed 11 cases of RSV-associated lower respiratory tract disease with two or more symptoms in patients given Abrysvo and 33 in patients given a placebo, a vaccine efficacy of 66.7%. Only 2 cases of RSV-associated lower respiratory tract disease with three or more symptoms occurred in patients given Abrysvo and 14 cases in patients given a placebo, resulting in a vaccine efficacy of 85.7%.
Role of the pharmacist
With the new vaccines expected to be available this fall, pharmacists can play a large role in helping patients to understand the potential benefits and risks of vaccination with Abrysvo or Arexvy.
Pharmacists should inform patients over the age of 60 years about the dangers of RSV-associated lower respiratory tract disease. They can also remind patients of the dangers of spreading RSV to other loved ones, particularly babies who are especially vulnerable to RSV.
Additionally, while these trials are ongoing and information is still being collected, it is important that pharmacists remember to encourage patients to report any adverse events to their health care provider or to the Vaccine Adverse Event Reporting System. ■