The Food and Drug Administration (FDA) recently approved the world’s first vaccine against respiratory syncytial virus (RSV), a highly contagious seasonal respiratory infection that affects people of all ages. The vaccine, called Arexvy, was developed by pharmaceutical giant GSK and is approved for adults aged 60 and over. However, the Centers for Disease Control and Prevention (CDC) will need to recommend the vaccine before it can be used widely. The agency’s advisory committee for immunizations is scheduled to meet in late June and may discuss the vaccine at that time.
RSV is a significant public health concern that can cause severe disease and is especially dangerous for infants and older adults. In the United States, bronchitis from RSV infections is the leading cause of hospitalization among infants under the age of 1. Older adults, particularly those with underlying health conditions, such as heart or lung disease or weakened immune systems, are at high risk for severe disease caused by RSV. Each year, RSV is estimated to cause between 60,000 to 160,000 hospitalizations and 6,000 to 10,000 deaths in older adults in the US.
Arexvy was shown to be highly effective in a randomized, placebo-controlled clinical study of adults aged 60 and over. In the study, the vaccine reduced the risk of developing lower-respiratory tract infection from RSV by 82.6 percent and the risk of developing severe RSV infection by 94.1 percent, according to the FDA. The approval of this first RSV vaccine is an important public health achievement to prevent a disease that can be life-threatening, said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research.
GSK hailed the approval of Arexvy as a turning point in the effort to reduce the significant burden of RSV. Pfizer and Moderna also have RSV vaccines in development. Pfizer has an RSV vaccine for adults aged 60 and up that was almost 86 percent effective against severe disease in a phase III trial. It is currently under review by the FDA and is expected to gain approval this month. In January, Moderna announced that its RSV vaccine for older adults was 82 percent effective against severe disease.
Pfizer is also working on a vaccine to protect infants, which is nearing a regulatory decision. In a phase III trial, the vaccine was 82 percent effective at preventing severe RSV in infants’ first three months and 69 percent effective over the first six months when given to pregnant participants.
The approval of the RSV vaccines marks a significant milestone for researchers who have spent decades working to find a safe and effective design for the immunizations. In the 1960s, small trials of early vaccine candidates led to children developing more severe RSV than unvaccinated children, and two vaccinated children died following their infections. Subsequent research showed that those early, ill-fated vaccines presented a key protein—the F protein—in the wrong conformation, prompting the immune system to generate impotent antibodies and exaggerated inflammatory responses that made the disease worse. It wasn’t until decades later that researchers at the National Institutes of Health figured out how to lock the F protein into a conformation that would induce an effective immune response, paving the way for the current vaccine designs.
The FDA’s approval of the first RSV vaccine is a significant milestone for researchers and a crucial step forward in the fight against this deadly respiratory illness. The approval of additional vaccines from Pfizer and Moderna is expected to further expand the availability of effective RSV vaccines, offering hope for reducing the burden of this disease on individuals and the healthcare system. The CDC’s advisory committee for immunizations will meet later this month to discuss the vaccine’s use, and we look forward to seeing their recommendations for the widespread use of the Arexvy vaccine. It is crucial to prioritize the vaccination of those who are at the highest risk of severe disease caused by RSV, such as infants and older adults with underlying health conditions. With continued research and development, it is possible that we will see even more effective RSV vaccines in the future.