Scientists are making progress on developing a vaccine for respiratory syncytial virus (RSV), the leading cause of hospitalization among infants.
On Tuesday, Pfizer announced that their RSV shot given to pregnant people was 70% effective at preventing severe RSV in infants from birth to the first six months of life.
The company plans to apply for approval from the Food and Drug Administration later this year.
The news comes at a time when RSV is surging across the country, particularly among young children.
Though RSV commonly causes respiratory systems, like a runny nose and a hacking cough, it can become severe and lead to pneumonia or a type of lung inflammation called bronchiolitis in at-risk populations like infants and older adults.
New research into RSV vaccines for children and adults
There is a growing body of research on potential RSV vaccines.
A recent clinical trial funded by AstraZeneca found that one of the vaccine candidates was 75% effective at preventing infections requiring hospitalization among infants.
Clinical trials have also found RSV shots to be highly effective in older adults and pregnant people (who can pass the antibodies to their fetus via the placenta).
Because the evidence has been so promising, health experts say it won’t be long until we have an RSV shot ready for use.
“It is likely that within a year high-risk adults will have several approved RSV vaccines,” Dr. Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security and an infectious disease expert, told Healthline.
Why don’t we have an RSV shot yet?
There are currently no vaccines for RSV. High-risk infants and premature babies are given a monoclonal antibody therapy called Synagis once a month during RSV season.
Scientists have been trying to develop an RSV vaccine for decades, however, several of the vaccine candidates have failed in testing.
“RSV vaccines are traditionally thought of as the graveyard of pharmaceutical companies as several candidates have failed,” says Adalja.
According to Bernadette Boden-Albala, DrPH, director & founding dean of University of California, Irvine’s Program in Public Health, the vast majority of people diagnosed with RSV have, typically, recovered smoothly so there hasn’t been an urgent need to develop a shot for it.
In recent years, however, RSV’s burden has worsened. In serious cases, patients may require additional oxygen or intubation with mechanical ventilation.
“The severity of RSV over the last year including significant hospitalizations around difficulty breathing in babies and young children have reinstated investigations around vaccine development,” Boden-Albala said.
A recent studyTrusted Source also sparked concerns that RSV could combine with influenza in our cells and form a new type of pathogen, however, that study was conducted in a laboratory and cannot be applied to how viruses behave in the real-world, says Adalja.
When will see an RSV vaccine?
Adalja says that the vaccine developers who were instrumental in the development of the COVID vaccines recently uncovered a new vaccination method that will improve how the immune system deals with viruses like RSV.
The vaccines will freeze a part of the virus before it fuses with our cells to give the immune system the opportunity to produce antibodies that can neutralize the virus before it does any damage.
“Several pharmaceutical companies are now racing to develop a vaccine for adults (a pediatric vaccine may be a little further away) and phase 3 vaccine trials which were just presented at several meetings are very promising in terms of efficacy and safety,” Adalja said.
While RSV shots will likely be available for high-risk adults by next fall, we will likely have to wait a bit longer until an RSV shot for children is approved and available, Adalja added.
The bottom line on RSV:
Public health experts expect that we’ll have a vaccine for RSV within the year. Recent evidence from clinical trials have found that some of the RSV shots being tested are highly effective at preventing severe disease. The news comes as RSV cases exploded across the country, triggering one of the worst nationwide outbreaks in years.