Anna Edney and Robert Langreth, Bloomberg Business: October 22, 2020
About two dozen outside advisers to the FDA with expertise in infectious diseases met Thursday to weigh in on agency standards that require a vaccine to work in at least 50% of people and for drugmakers to collect two months of safety data on at least half of clinical trial volunteers.
“They haven’t gone far enough” in terms of safety, said Hayley Altman-Gans, a panel member and pediatrics professor at Stanford University Medical Center.
Many panel members and outside researchers who commented during the hearing worried that if a vaccine is rushed out that later turns out to have safety problems or to be less effective than promised, it could backfire in a big way, undermining public confidence in Covid-19 vaccines for years to come.
Archana Chatterjee, advisory panel member and dean of Chicago Medical School, said the public has a lot of concern about safety. Meanwhile, she added, “What we’re being asked to do is to build this plane as we fly it.”
Several panel members expressed concern that the two-month safety follow-up the FDA is calling for before a vaccine gets an emergency authorization is simply not enough. In addition to safety, it means that doctors won’t know whether a vaccine’s efficacy could fade after just a few months.
Panel member Amanda Cohn, who is chief medical officer at the National Center for Immunization and Respiratory Diseases, worried that the efficacy of vaccines that just meet the 50% threshold after two months may see reduced effectiveness a few months later if the shot doesn’t offer a long period of protection.
“Very rarely do we look at [vaccine efficacy] so shortly after completing a series,” according to Cohn, whose organization is part of the Centers for Disease Control and Prevention.
The advisers weren’t alone in questioning the standards. Diana Zuckerman of the National Center for Health Research told the committee the vaccine trials “have serious design flaws.”
The two-month follow up the FDA has asked for is too short to establish how long a vaccine will work, and the trials are too geared to preventing mild infections, and may not show whether they prevent severe infections and hospitalizations, she said.
Longer follow-up may be especially important because some of the first vaccines, including messenger RNA vaccines from Pfizer Inc. and Moderna Inc., are based on new technologies that have never been used in an approved product.
The debate over the rigor of the FDA guidelines was one of two main issues debated before the committee, which heard comments from regulators, drugmakers and the public. The second questioned whether trial participants on a placebo should be advised when a vaccine is deemed to be safe and effective.
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