On May 3, the Food and Drug Administration (FDA) approved the first vaccine — Arexvy — for respiratory syncytial virus (RSV) to lower respiratory tract disease in people older than 60 years. This is the first RSV vaccine to be approved anywhere in the world.
The vaccine is manufactured by the company, GSK, and the FDA approval was based on a phase-3 trial carried out on nearly 25,000 participants. About 12,500 participants received one dose of the vaccine, while the remaining participants received a placebo. The trail showed that a single dose of the vaccine reduced the risk of people, older than 60 years, developing lower respiratory tract disease caused by the RSV virus by 82.6% and reduced the risk of developing severe disease by 94.1%.
The results were published in February in The New England Journal of Medicine.
Comorbidities
According to the U.S. Centres for Disease Control and Prevention, lower respiratory tract disease caused by the RSV virus leads to approximately 60,000-1,20,000 hospitalisations and 6,000-10,000 deaths among adults who are 65 years of age and older. The RSV virus significantly affects older adults with comorbidities. Like the common cold, the RSV usually causes mild symptoms but can turn deadly if it infects older people.
Besides older adults, infants too are at high risk from RSV. According to the Atlanta-based CDC, every year, 58,000 to 80,000 children in the U.S. who are younger than five years are hospitalised because of the RSV and the mortality is 100 to 300.
As per a GSK press release, the vaccine will be available for older adults in the U.S. before the 2023-2024 RSV season, which typically starts ahead of the winter months.
Two more vaccines for RSV by Pfizer and Moderna have already completed clinical trials on adults older than 60 years and may soon be approved by the FDA. While the vaccine developed by Pfizer is protein-based, Moderna has used mRNA technology, like in the case of the SARS-CoV-2 vaccine, to develop the RSV vaccine.
GSK is also testing the vaccine in adults aged 50-59 years, including participants with underlying comorbidities. The results are expected by the end of this year.
As per a January 2023 press release by Moderna, its vaccine has 83.7% efficacy in preventing RSV-associated lower respiratory tract disease. It was tested on nearly 37,000 adults, 60 years or older in 22 countries.
In 2013, Barney Graham at the Morehouse School of Medicine in Atlanta, Georgia and other scientists identified the key protein — protein F which is yet to fully fuse with a human cell — responsible for the RSV virus to infect human cells. They found that this protein, introduced in humans, elicited neutralising antibodies against the virus.
