More than eight months ago, large studies found that both the Pfizer-BioNTech and Moderna COVID-19 vaccines reduced the risk of illness by more than 90%. Yet the U.S. Food and Drug Administration has not yet granted them full approval, to the dismay of public-health officials eager to boost vaccination rates as the delta variant sends infections skyward.
So what's the holdup?
Part of the reason, according to experts in drug regulation, may be simply that the agency can afford to take the time.
In December, the FDA authorized the first two vaccines for emergency use, and did so for a third in February. Those authorizations, though based on extensive, rigorous research, are temporary in nature. Before granting permanent approval ("licensure"), the agency can spend months to make triply sure that all regulatory requirements are met, given that the vaccines are available for all who want them in the meantime.
"Any decision to grant such an approval is a potential precedent in the future, so you don't want to rush something through," said Adam Muchmore, a law professor at Pennsylvania State University.
Still, with the emergence of the highly transmissible delta variant of the coronavirus, public-health officials are eager for the agency to move forward, contending that full approval may pave the way for more people to be vaccinated.
That could happen in two ways. Physicians hope that if the agency licenses the drugs, some who are hesitant about vaccination may become more receptive. Even if not, more businesses and institutions may decide they have a legal basis for requiring the shots, said Greer Donley, an assistant professor at the University of Pittsburgh Law School.
Hundreds of universities already have instituted vaccine mandates for students enrolling this fall, in one case surviving a challenge in federal court. And on Monday, the U.S. Department of Veterans Affairs announced it would require the shots for 115,000 frontline medical workers. But with full approval, Donley said, employers seeking to require the vaccines may feel they are on even firmer legal ground.
Either way, FDA's career civil servants, accustomed to carrying out their careful reviews in relative obscurity, are under public pressure like never before.
"If it were to move too fast, that would be evidence that skeptics would use, that the FDA is acting politically, not acting based on science," Donley said. "The FDA is walking on this tightrope to make sure it is acting as quickly as possible but also following all its protocols."