Blood sample for respiratory syncytial virus (RSV) test
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Independent advisors to the Food and Drug Administration on Tuesday recommended Pfizer’s RSV vaccine for adults 60 and older despite safety concerns after two people who received the shots developed a rare neurological disorder.
A majority of FDA committee members supported the vaccine, but they grappled with differing views on whether safety and efficacy data are sufficient to support approval by the agency. The FDA is expected to make a decision in May.
There is currently no vaccine to protect older adults from respiratory syncytial virus, which kills thousands of seniors each year. Pfizer’s shot could become the first to get FDA approval.
In an earlier vote on Tuesday, seven members of the FDA committee said the safety data was sufficient for approval, while four said it was not, and one member abstained.
The vote came after concerns between the FDA and advisory committee members about two cases of Guillain-Barre syndrome among about 20,000 vaccine recipients. Guillain-Barre is a rare neurological disorder in which the body’s immune system mistakenly attacks the nerves.
Symptoms can range from brief weakness to paralysis. Most patients, even those with severe cases, recover.
In a second vote, seven committee members said vaccine effectiveness data was sufficient, while four said it was not, and one member abstained.
The shot was about 86% protective against a lower respiratory tract illness with three or more symptoms, and 66.7% effective against the same condition with two or more symptoms, according to an FDA review of Pfizer’s data. Symptoms included wheezing, shortness of breath, rapid and shallow breathing as well as mucus production.
According to the Centers for Disease Control and Prevention, among adults age 65 and older, RSV causes 6,000 to 10,000 deaths and 60,000 to 160,000 hospitalizations per year. The risk of hospitalization increases with age, and adults 70 and older are more vulnerable.
According to data from the CDC for three seasons, among adults of all ages hospitalized with RSV, 19% required intensive care and 4% died. The death rate is highest among senior citizens.
Pfizer’s vaccine contains both strains of RSV, which circulate at the same time during the fall and winter. The shot is administered as a single 120 microgram dose.
The FDA considers two Guillain-Barre cases during the trial to be possibly linked to the vaccine, said Dr. Nadine Peart Akindele, an agency official. The FDA has asked Pfizer to develop a safety study that would monitor Guillain-Barré risks following an approval, which the company has agreed to do.
A 66-year-old man in the US developed Guillain-Barré, and a woman of the same age in Japan was diagnosed with Miller Fisher syndrome, a variant of Guillain-Barré. They developed symptoms seven and eight days after vaccination, respectively. According to the FDA, the woman has since recovered, and the man’s symptoms were resolving as of last update.
But Pfizer executive Alejandra Gertmann said the company did not identify any safety concerns during the trial and the vaccine was well-tolerated.
Gertman pointed to other possible causes for the Guillain-Barre cases, noting that the man had suffered a heart attack and the woman had an upper respiratory tract infection. But Dr. Mary Griffin, a member of the FDA’s advisory committee, said the cases raise serious safety concerns.
Griffin, professor of health policy at Vanderbilt University Medical Center, said, “I feel like case one is a red flag. The two cases are very related and it’s a concern to me that Pfizer doesn’t think there are any safety concerns.” “
FDA says safety monitoring is important
Dr. Hana El Sahli, who chairs the FDA advisory committee, also said that the Guillain-Barre cases pose a significant safety concern. Al Sahli said that the disease occurs in people aged 60 and over in one in 100,000, but the rate in testing appears to be one in 9,000.
“So it’s major if we take it to this stage,” Al Sahli said, noting that there is significant uncertainty about what the actual rate of disease will be among vaccine recipients. “But still, it is important in terms of incidence,” she said.
Dr. David Kaslow, a senior official in the FDA’s vaccine division, said safety monitoring would be “critically important” if Pfizer’s RSV vaccine is approved.
The FDA is currently reviewing Pfizer’s proposal to study the risk of Guillain-Barré syndrome among Medicare beneficiaries. FDA has the authority to require such studies after approval if the agency determines it is necessary.
incomplete efficacy data
According to the FDA, at the time of Tuesday’s meeting, there was not enough data to evaluate the effectiveness of Pfizer’s vaccine against severe disease requiring hospitalization, oxygen support or a mechanical ventilator. According to the agency, the data for how long the protection from the vaccine would last was also not available.
Pfizer also did not have data on how effective the vaccine is for elderly individuals with weakened immune systems or people in frail health, according to the FDA.
Griffin, a physician at Vanderbilt University Medical Center, said she was concerned that the vaccine was tested in a relatively healthy population, with fewer hospitalizations, and no data on nursing home residents and those in frail health.
Akindele, the FDA official, said real-world evidence after the vaccine rollout could provide answers as to how much protection it offers for those with fragile health. She said the data will be used to determine whether the FDA needs to make any adjustments to the way the shot is used.
Pfizer is conducting its clinical trial with over 34,000 people enrolled over two RSV seasons. Available efficacy and safety data are from the first season.
Asked what would happen if the data from the second season after approval is not as strong, Akindele said the FDA would re-evaluate the shot and meet with the committee again to determine how to proceed.
Pfizer estimates that if 50% of people age 60 and older get vaccinated, the vaccine could prevent more than 5,000 deaths, 68,000 hospitalizations, 51,000 emergency department visits, and more than 422,000 outpatient visits. Is.