By Christina Jewett
The Food and Drug Administrationlast week approved Pfizer’s vaccine against the respiratory syncytial virus, or RSV, for adults 60 and older, the second approval granted for shots offering protection from the virus in May.
GSK was the first drugmaker to get the FDA’s permission to market an RSV vaccine, on May 3. The vaccines are expected to be available in the fall before the winter RSV season.
Why it matters: Older adults are at a higher risk.
Each year, about 60,000 adults 65 and older are hospitalized with RSV and about 6,000 to 10,000 die from the virus, the FDA estimated. The Centers for Disease Control and Prevention estimated that in one year, more than 21,000 people in that age group would need to take the GSK vaccine to prevent one RSV death; the number was nearly 25,000 for the Pfizer shot.
The virus was a key driver in the winter’s “tripledemic” of COVID-19, flu and RSV that was particularly hard on young children, resulting in overwhelmed hospitals.
Infants and toddlers are also at elevated risk; RSV is considered a leading killer of infants globally. Several treatments, including a maternal vaccine and a monoclonal antibody for infants against RSV, are under agency review.
Background: Advisers aired safety concerns.
During an advisory meeting March 1 about both vaccines, doctors reviewed detailed data provided by the drugmakers.
Pfizer’s product, called Abrysvo, proved nearly 67% effective against cases of the virus with two symptoms and 86% effective against cases with three or more symptoms, according to data submitted to the FDA. The GSK vaccine, called Arexvy, was nearly 83% effective against severe RSV.
But the advisory panel also raised concerns about a few cases in which vaccine recipients developed autoimmune syndromes shortly after receiving the shots.
In a Pfizer study of about 34,000 patients who received the RSV vaccine, a week after the shot, one patient developed a life-threatening case of Guillain-Barré syndrome, a condition in which the immune system attacks the nervous system. A second patient developed a subtype of that condition called Miller Fisher syndrome eight days after receiving the shot.
Those cases put the incidence rate of the condition at about 1 in 9,000 — although they are typically seen at a rate of about 1 in 100,000 in the general population. Some advisers, also noting the low incidence of severe RSV in the patient pool, found those numbers troubling. The final vote of the FDA’s advisory panel in favor of the Pfizer vaccine’s safety and efficacy was 7-4. The panel voted 10-2 in favor of the GSK vaccine, which was also linked to one Guillain-Barré case and two others of a possibly related disorder.
What’s next: When will the shots be available?
CDC advisers are expected to discuss recommendations to health care providers about the shots in a meeting in June. So far, they have signaled that the data from the GSK and Pfizer trials support use of the vaccines in people ages 65 and older.
A Pfizer spokesperson, Jerica Pitts, said the company was ready to ship the vaccine. She did not know the price of the vaccine but said there would be no copay for vaccines deemed medically necessary under Medicaid and Medicare. GSK said earlier that its vaccine would be available in the fall.
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