- An FDA advisory panel voted today to recommend that the Pfizer RSV vaccine be approved for pregnant individuals.
- A recent study finds that an experimental RSV vaccine appears to be effective in protecting newborns against severe disease.
- The vaccine was effective against severe RSV-associated lower respiratory tract illness such as pneumonia and bronchiolitis in infants from birth through six months, results showed.
- Bronchiolitis is inflammation of the small airway passages entering the lungs.
A key FDA panel of independent advisors
The decision comes just over a month after company trials found that the RSV vaccine protected infants and older adults from illness caused by this virus.
The vote was not unanimous and some of the experts expressed concern that the vaccine could increase the risk of premature births.
The FDA does not have to follow the recommendations of the Vaccines and Related Biological Products Advisory Committee, but they traditionally do.
In one trial, whose results were published April 5 in the The New England Journal of Medicine, the vaccine was given during late-stage pregnancy.
The vaccine was effective against severe RSV-associated lower respiratory tract illness such as pneumonia and bronchiolitis in infants from birth through six months, results showed.
Bronchiolitis is inflammation of the small airway passages entering the lungs.
“By immunizing pregnant women with this vaccine, the women generate antibodies and those antibodies cross the placenta and provide protection to the infant in the early months of life,” Dr. Coleen Cunningham, professor and chair of pediatrics at University of California, Irvine, who was not involved in the trials, told Healthline.
The vaccine was 82% effective during the first 90 days of life and 69% effective over the first 6 months of life.
This decline in effectiveness is expected, said Cunningham, because antibody levels in the infant diminish over time.
However, “this strategy [of vaccinating a pregnant mother] is expected to be very helpful during the first several months of life,” she said, “which is a time that the children are most vulnerable.”
Researchers did not identify any safety concerns in infants or women who received the vaccine.
Pfizer has asked the Food and Drug Administration to approve its RSV vaccine for pregnant people to protect infants. The company said it expects a decision by August 2023.
The FDA is also reviewing an application from AstraZeneca for its monoclonal antibody treatment designed to protect children up to 2 years old from RSV.
In another company-funded trial, the Pfizer RSV vaccine was 67% to 86% effective in adults 60 and older against RSV-associated lower respiratory tract illness, such as acute bronchitis and pneumonia
It was also 62% effective against RSV-associated acute respiratory illness.
The results were published April 5 in the The New England Journal of Medicine.
Researchers did not identify any safety concerns in this age group, and the rates of adverse events were similar in vaccine recipients and the inactive placebo group.
Three serious adverse events identified in vaccine recipients were thought to be related to the vaccine, results show.
The first was a delayed allergic reaction. The other two were consistent with
If these vaccines are approved by the FDA, the agency and the Centers for Disease Control and Prevention will continue to monitor their safety.
Pfizer is seeking FDA approval of its RSV vaccine for adults 60 years and older.
Earlier this month the FDA approved the first ever RSV vaccine. But that vaccine made by GlaxoSmithKline (GSK) is only approved for people over age 60
If the agency signs off on these vaccines, they could become the world’s first approved RSV vaccines.
Johnson & Johnson’s vaccine division, Janssen, announced in March that it was ending work on its RSV vaccine candidate.
Denmark-based Bavarian Nordic expects results from a clinical trial of its RSV vaccine for older adults in the middle of this year.
RSV is widespread and highly contagious. Most children will get RSV infection by age two,
But people can get infected at any age and multiple times during their lifetime, the agency says.
RSV usually causes a mild infection for most people, with cold-like symptoms such as runny nose, coughing, sneezing, fever and decreased appetite.
For infants under 6 months and older adults, though, RSV can be serious enough to cause hospitalization or death.
In the United States, RSV is responsible for up to 80,000 hospitalizations and up to 300 deaths each year among children younger than age five, according to the National Foundation for Infectious Diseases.
In addition, RSV causes up to 160,000 hospitalizations and up to 10,000 deaths in adults age 65 years and older, the foundation reports.
There is currently no specific treatment for RSV infection. Treatment involves managing symptoms and providing supportive care.
Dr. David Diemert, a professor of medicine and microbiology, immunology and tropical medicine at George Washington University School of Medicine & Health Sciences, in Washington, D.C., said Pfizer’s RSV vaccine is a very important development, in particular for protecting young children.
“Newborns and infants bear the brunt of this respiratory infectious disease in terms of severity, particularly babies born prematurely,” Diemert, who was not involved in the trials, told Healthline.
“Vaccinating pregnant women is a proven and safe way of getting high levels of antibodies to babies that will protect them against invading viruses and other disease-causing organisms,” he said.
Diemert said the George Washington University Vaccine Research Unit is about to start recruiting 18- to 60-year-olds for a phase 3 clinical trial of Pfizer’s RSV vaccine.
This trial will focus on adults in this age group who are at higher risk of developing severe disease due to the RSV virus because of coexisting medical conditions such as asthma, diabetes or chronic kidney disease.
Researchers will also be enrolling adults of any age who are immunocompromised.
“This study will be looking at the safety of the vaccine in these populations,” said Diemert, “and [will] also verify that the immune response produced by the vaccine is similar to what’s been seen in the other successful studies done to date.”