"The FDA recognizes that vaccines are key to ending the COVID-19 pandemic and is working as quickly as possible to review applications for full approval," FDA spokesperson Alison Hunt said in a statement.
But critics maintain that full approval of the Pfizer and Moderna vaccines, beyond the temporary approval that they currently have, needs to happen quicker. The argument is that the vaccine has proven to be safe and effective, and full FDA approval could increase Americans' confidence in the vaccines at a time when the country is teetering dangerously at just 50% full vaccination while up against the fast-spreading delta variant.
"I think a lot of us are baffled why the FDA is taking so long," Dr. Ashish Jha, dean of the Brown University School of Public Health, said on ABC's "Good Morning America" on Monday.
The FDA will surely approve of the vaccines, Jha said, but needed to "move a bit faster now."
So what do we know about the timeline?
Full approval of a vaccine under priority review, as both Pfizer and Moderna are, usually takes six months. The FDA has said it intends to complete it much quicker than that, and Dr. Anthony Fauci, chief medical adviser to the White House, recently said he expected full approval for Pfizer in a month or so, by August, and Moderna to follow thereafter.
Pfizer submitted for full approval on May 7, almost three months ago, and Moderna on June 1, almost two months ago. So, the decision should not be too far off.
And what does FDA say about the criticism that it's moving too slowly?
Asked by ABC News on Monday if the review is moving slower than anticipated, the FDA stood by the process.
FDA spokesperson Alison Hunt said that reviewing the vaccines is "among the highest priorities of the agency, and the agency intends to complete the review far in advance of the PDUFA Goal Date." The goal date is January 2022, though that's a regulatory deadline and not when it's expected.
"The FDA recognizes that vaccines are key to ending the COVID-19 pandemic and is working as quickly as possible to review applications for full approval," Hunt said.
The FDA also emphasized that the current authorization -- an Emergency Use Authorization -- was conducted thoroughly, signaling that it stands on solid ground and should be fully approved.
"Although an authorization is not an FDA approval, the FDA conducted a thorough scientific evaluation of each of the authorized vaccines and can assure the public and medical community that the vaccines meet FDA's rigorous standards for safety, effectiveness and manufacturing quality," Hunt said.
Some have also argued that the FDA has to take its time so that any vaccine mandates that follow the full approval go as smoothly as possible. Any cracks in the approval process or accusations of rushing, could lead to even more pushback. That's already played out over the last few months, as hesitant Americans have refused to take the vaccine because they fear it was given emergency authorization too hastily.
That was White House press secretary Jen Psaki's defense on Monday.
"The FDA is the gold standard in our view, and they move at the speed of science," Psaki said to ABC News Chief White House Correspondent Cecilia Vega, who asked why the FDA hadn't yet given full approval of the vaccines.
"It wouldn't be responsible to expedite that process at a faster speed than the science and data allows."
ABC News' Shannon Crawford contributed to this report.