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After a 60-year scientific search, the world has its first vaccine to protect against respiratory syncytial virus, or RSV, and more are on the way.
On Wednesday, the US Food and Drug Administration Arexvy approved, made by GSKIt is designed to be given as a single injection to adults 60 years of age and older.
It could be available to seniors as soon as this fall, pending a recommendation for use from the US Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices, which will meet in June. .
“Older adults, particularly those with underlying health conditions such as heart or lung disease or weakened immune systems, are at high risk of serious illness caused by RSV,” said Dr. Peter Marks, director of the Center for FDA Evaluation and Analysis of Biological Products. Investigation, in a statement. “Today’s approval of the first RSV vaccine is an important public health achievement in preventing a potentially life-threatening disease and reflects the FDA’s continued commitment to facilitating the development of safe and effective vaccines for use in the USA”.
Although RSV is a disease often associated with infants and young children, it can also be dangerous for older people. In the US, approximately 159,000 adults 65 years and older are hospitalized each year with RSV, and approximately 10,000 to 13,000 die as a result of their infection.
“RSV is certainly an important disease in the elderly. Within a few years, the burden of RSV disease approaches the burden of influenza in the elderly. And this is really a wonderful development,” said Dr. Ruth Karron, a professor of international health at the Johns Hopkins Bloomberg School of Public Health, who was not involved in the development of the vaccine.
In a clinical trial of nearly 25,000 older adults, the results of which were published in the New England Journal of Medicine, the GSK vaccine was 83% effective in preventing lower respiratory tract disease caused by the virus.
Lower respiratory tract disease was defined in the study as a positive test and two other symptoms for at least one day, including new or worsening cough, wheezing, shortness of breath, increased respiratory rate, low blood oxygen, or crackles in the the lungs, which a doctor would collect with a stethoscope.
The vaccine was 94% effective in preventing serious illness in older people. People were considered to have severe illness if they needed supplemental oxygen or needed mechanical help to breathe, such as a ventilator.
GSK’s RSV vaccine works by using a small part of the virus: a protein that sticks out on its surface called the fusion protein, or F, which helps the virus attach to and infect cells in the body’s upper respiratory tract. The protein pieces of the vaccine are made in a laboratory, using cells specially programmed to make them.
The vaccine builds on a seminal discovery made a decade ago by researchers at the National Institutes of Health, including some of the same scientists who helped make the Covid-19 vaccines.
Normally, the F protein is wavy, moving from side to side, changing shape after fusing with a cell.
The NIH researchers figured out how to freeze the protein in the form it takes before fusing into a cell. In this way, the body can develop strong antibodies against it.
The GSK vaccine uses this potent prefusion form of the protein, along with an ingredient called an adjuvant, which increases immune activity.
When the researchers looked specifically at how well the vaccine worked in the most vulnerable older people — those with underlying health conditions like COPD, heart failure or heart disease — they found it was 94% effective in preventing lower respiratory tract infections.
“That is really exceptional information, because that is the type of disease that we want to prevent. We want to prevent people from ending up in hospital with RSV,” said Dr. Len Friedland, GSK’s director of scientific affairs and public health.
The most common side effects reported by people in the clinical trial included pain at the injection site and fatigue. Those usually resolve within a day or two.
There were a small number of serious adverse events in the study. Friedland said they were balanced between the group that received the vaccine and the group that received the placebo. He says that researchers will continue to monitor safety signals as the vaccine rolls out to a broader population.
The FDA said it requires GSK to continue monitoring for signs of Guillain-Barré syndrome, a nerve disorder that can cause paralysis or weakness that rarely follows viral infections and vaccination. It also requires the company to study the risk of a condition called acute disseminated encephalomyelitis, a rare type of inflammation that affects the brain and spinal cord. The FDA says two people in the vaccine’s clinical trials developed the condition after receiving that shot along with a flu shot.
It’s not clear exactly how long the protection from the vaccine will be, Friedland said. The researchers are following the study participants for three years and will continue to evaluate the efficacy of the vaccine over time. So far the protection seems to hold up well for about a year.
Three other RSV vaccines for older adults are also in the final stages of testing.
The FDA is expected to make a decision on Pfizer’s RSV vaccine for older adults in late May. The agency is also reviewing Pfizer’s maternal vaccine to protect babies and is expected to make a call on it in late August.
Moderna is completing its Phase 3 trial of an RSV mRNA vaccine in older adults and expects to submit the results to the FDA for approval in the coming months.
Bavarian Nordic, maker of the Jynneos mpox vaccine, says it will report results from a Phase 3 trial of its RSV vaccine for older adults this year.
Paul Chaplin, the chairman and chief executive of Bavarian Nordic, says there’s a saying in Britain that you wait a long time for a bus and then four show up at once. The race to the finish line for an RSV vaccine is a bit like that, he says.
“We have been waiting for decades for an effective and safe RSV vaccine, and there have been numerous attempts that have failed,” Chaplin said.
“And I know that GSK is likely to get the first approval, but there are others on the way, including us. And I think that’s fantastic, because RSV is a huge unmet medical need that many people underestimate, and hopefully now we’ll have a series of effective vaccines that will help protect people.”
The search for an effective RSV vaccine is a story of scientific triumph over tragedy.
In the 1960s, two children died and many others were hospitalized with severe RSV when the experimental vaccines they had been given turned out to ameliorate the infection rather than defend against it.
That study tested a vaccine made with an RSV virus that had been chemically treated to render it inert and mixed with an ingredient called alum, to wake up the immune system and help it respond.
It was tested at clinical trial sites in the US between 1966 and 1968.
At first, everything looked good. The vaccine was tested in animals, which tolerated it well, and then given to children, who also seemed to respond well.
Unfortunately, when RSV season began that fall, many of the children who were vaccinated required hospitalization and contracted more severe RSV illness than would normally occur.
One study on the trial found that 80% of vaccinated children who contracted RSV later required hospitalization, compared to only 5% of children who received a placebo. Two of the young trial participants died.
The results were a seismic shock to vaccine science. Efforts to develop RSV vaccines and treatments came to a halt as researchers tried to untangle what went so wrong.
Many of the protective measures currently in place around vaccine clinical trials arose from the failures of the RSV vaccine.
The scientific breakthrough that allowed scientists to freeze the virus’s F protein in place also allowed NIH scientists Drs. Jason McLellan and Barney Graham to stabilize the coronavirus spike protein, accelerating the development of a covid-19 vaccine.
“RSV has been one that has taken us a while to unlock its mysteries and secrets,” said Dr. Steven Varga, dean of the Graduate School of Biomedical Sciences at St. Jude Children’s Research Hospital, who has spent his career studying the virus. and has designed a nanoparticle vaccine against it.
“It’s a really exciting time. It has been a long time coming,” she said.
Graham, now a professor at Morehouse Medical School, agreed that the news is exciting, but says there is more work to be done.
“You can imagine that after a lifetime of work at RSV, it is exciting and rewarding to reach this milestone. However, there is still much more to do. The success with vaccinations for the elderly and maternal immunization and monoclonal antibody treatment for infants still leaves children 6 months to 5 years in need of protection,” he wrote in an email.
Tania Richter, a Minnesota resident, wishes the vaccine had been available for her grandfather Adam Kaseman, a retired school bus driver who died after a severe bout of RSV last summer. He was 95 years old but otherwise in good health and living in an assisted living facility in Jamestown, North Dakota, when RSV traversed the facility.
He was hospitalized and later recovered enough to be released to a nursing home, but Richter said it was the beginning of the end for him. He died a few weeks later.
“He was a great-grandfather. I didn’t get to see it too much in the last few years, just with Covid, trying to keep everyone safe, I prevented that from happening,” he said.
“I really wish it had been around before this happened because vaccines give us a fighting chance,” he said. “Hopefully, it will save someone else’s grandfather.”
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