The Food and Drug Administration issued the world’s first approval for a respiratory syncytial virus (RSV) vaccine, an achievement researchers worked on for decades after a disastrous clinical trial in the 1960s.
The vaccine, called Arexvy from pharmaceutical giant GSK, is approved for adults 60 and older. The Centers for Disease Control and Prevention will need to recommend the vaccine before it is available for use. The agency’s advisory committee for vaccinations is then due to meet June 21-22 and could then discuss the vaccine.
RSV is a common and highly contagious seasonal respiratory infection. It is often associated with infants, who are at particularly high risk of developing serious disease. In fact, bronchitis due to RSV infections is the leading cause of hospitalization in infants under 1 year of age in the United States. But the virus is also dangerous for the elderly, causing an estimated 60,000 to 160,000 hospitalizations and 6,000 to 10,000 deaths among the elderly each year in the country.
In an ongoing, randomized, placebo-controlled clinical study in adults aged 60 and over – in which approximately 12,500 participants received Arexvy and 12,500 participants received a placebo – the vaccine reduced the risk of developing RSV lower respiratory tract infection. , and reduced the risk of developing a serious RSV infection by 94.1%, the FDA noted.
“Older people, especially those with underlying health conditions, such as heart or lung disease or a weakened immune system, are at high risk of serious illness from RSV,” said Peter Marks, director of the FDA Center for Biologics Evaluation and Research. The approval of this first RSV vaccine on Wednesday is “an important public health achievement in preventing a disease that can be life-threatening”, he added.
Triumph after tragedy
GSK also celebrated the historic approval, with GSK Chief Scientific Officer Tony Wood saying the approval “marks a milestone in our efforts to reduce the significant burden of RSV”.
GSK’s vaccine is just the first of several RSV vaccines in the works. Pfizer offers an RSV vaccine for adults 60 and older that was nearly 86% effective against serious disease in a phase III trial. It is currently being reviewed by the FDA and is expected to be approved this month. In January, Moderna said its RSV vaccine for the elderly was 82% effective against serious illnesses.
Pfizer also has a vaccine to protect infants that is nearing a regulatory decision. When given to pregnant participants in a phase III trial, the vaccine was 82% effective in preventing severe RSV in the infant’s first three months and 69% effective in the first six months.
The vaccines are a triumph after researchers spent decades working to find a safe and effective design for immunizations. Small trials of early candidate vaccines in the 1960s led to children developing more severe RSV than unvaccinated children. Two vaccinated children died from their infections.
Later research showed that these early doomed vaccines presented a key protein – protein F – in the wrong conformation, prompting the immune system to generate helpless antibodies and exaggerated inflammatory responses that worsened the disease. It wasn’t until decades later that National Institutes of Health researchers discovered how to lock the F protein into a conformation that would induce an effective immune response, paving the way for current vaccine designs.