'A good day': FDA approves world's first RSV vaccine

The pharmaceutical company GSK beat competitors when it had its respiratory syncytial virus (RSV) vaccine approved first.Credit: iStock/Getty

The US Food and Drug Administration (FDA) has approved GSK’s vaccine against respiratory syncytial virus (RSV) for use in people aged 60 years and older. This is the first RSV vaccine to gain approval anywhere in the world, and researchers are celebrating.

“It’s a very big deal to have options available to prevent RSV disease,” says Barney Graham, senior adviser for global-health-equity trials at Morehouse School of Medicine in Atlanta, Georgia.

Will a new wave of RSV vaccines stop the dangerous virus?

RSV usually causes mild symptoms similar to those that arise during a common cold. But for older people, it can be deadly. According to the US Centers for Disease Control and Prevention (CDC), each year RSV kills approximately 6,000 to 10,000 adults in the United States who are 65 years or older, and sends 60,000 to 160,000 to hospital. People in this age group with comorbidities such as chronic obstructive pulmonary disease, asthma or congestive heart failure are especially at risk.

The FDA approved GSK’s RSV vaccine, to be sold as Arexvy, on the basis of phase III clinical-trial data submitted by the pharmaceutical company, which is based in London. Those data showed that the shot reduced the risk of people aged 60 and older developing lower respiratory tract disease from RSV by 82.6% and that of developing severe disease by 94.1%. The results were published in February in The New England Journal of Medicine1.

The approval is “a tremendous opportunity to help address a really important public-health need”, says Leonard Friedland, vice-president and director of scientific affairs and public health for GSK’s US vaccines division.

The FDA expedited the approval of GSK’s vaccine last November, during a period when the United States was grappling with a ‘tripledemic’ of people with RSV, influenza or COVID-19 flooding hospitals.

The race to make vaccines for a dangerous respiratory virus

The technology underlying the RSV vaccine has been almost 60 years in the making. In the 1960s, during a clinical trial of an RSV vaccine, two of the participating children died and 80% ended up in hospital2. Understanding what had happened and finding a solution became Graham’s life’s work. “The first 20 years were spent primarily working out how to make a vaccine that could be safe,” he says.

The original vaccine contained an inactivated RSV virus. Eventually, the vaccine-research community pivoted its strategy.

In 2008, Graham teamed up with Jason McLellan and Peter Kwong at the US National Institutes of Health in Bethesda, Maryland, and others to investigate the structural biology of RSV. Over time, they learnt that the virus used protein F, a molecule on its surface, to infect human cells. With this knowledge, protein-based RSV vaccines could be developed that would introduce the molecule into cells to produce an immune response.

But the team eventually found that early jabs of this type had been designed around the wrong form of protein F, a ‘postfusion’ version that arises after the virus and cell have already joined. The researchers discovered a way to instead target the correct form of protein F, which hasn’t yet fully fused with any cell and was found to elicit neutralizing antibodies. They published their findings in 20133.

Their work paved the way for companies such as GSK, Pfizer and Moderna to develop the RSV vaccines in the pipeline today. “This is my lifetime’s work. It’s very gratifying to see this finally happening,” Graham says. “It’s a good day for RSV.”

After the approval of GSK’s vaccine, scientists hope others will follow. “There are many patients all around the world who can benefit from vaccination,” Friedland says.

RSV wave hammers hospitals — but vaccines and treatments are coming

The pharmaceutical firm Pfizer, based in New York City, has also developed a protein-based RSV vaccine for people aged 60 and older that the FDA is expected to approve later this month. Biotechnology company Moderna in Cambridge, Massachusetts, has an mRNA-based vaccine for preventing RSV in adults in the same age group under expedited review at the agency.

Moreover, an FDA advisory panel will convene on 18 May to consider the safety and effectiveness of Pfizer’s RSV vaccine for pregnant people. During a phase III clinical trial, pregnant people who received the jab gave birth to newborn babies who were then monitored for illness. The vaccine reduced the risk of infants up to 90 days old having a severe lower respiratory tract illness from RSV by 81.8%4. The FDA will decide whether to approve the vaccine by August.

Like older adults, babies are at high risk from RSV. “RSV seems like a harmless thing,” but it’s not, says Mina Suh, a scientist at the company EpidStrategies who is based in Irvine, California, that evaluates epidemiological studies. Each year, 58,000 to 80,000 children in the United States who are aged 5 years and under are hospitalized because of RSV and 100 to 300 die, according to the CDC.

Newborn babies’ immune systems don’t respond robustly to many vaccines, so it is challenging to give them shots directly. To protect infants, Pfizer opted to immunize pregnant people a few months before they gave birth. Their bodies make the antibodies that are transferred to their newborn.

But before this next tranche of vaccines is approved, GSK’s jab will move ahead. It is expected to be approved in Europe soon. And the next step in the US process is for the CDC’s Advisory Committee on Immunization Practices to weigh in. The panel will recommend who can receive the GSK jab, how it is given and when it will it be available to the public. The committee’s next meeting is in June. This is an important step, Friedland says. “Vaccines don’t save lives. It’s vaccination that does.”

Correction 04 May 2023: An earlier version of this story spelled researcher Jason McLellan’s name incorrectly.