Why is the review of the data taking so long? The FDA takes the raw data that companies provide and reanalyzes them, often picking apart statistical calculations made by manufacturers. Among regulators the world over, there is no similar direct check on the data produced by pharmaceutical manufacturers.

This type of analysis, routine for new drug approvals at the FDA, is not legally necessary for emergency use authorizations during a pandemic. But given that Covid-19 vaccines could be given to hundreds of millions of people, the agency decided a thorough review was needed. In an interview with the Wall Street Journal, Hahn, the FDA commissioner, said staffers are working long hours in parallel seeking to prepare.

To insiders at the FDA, even the current timeline seems insanely compressed; one insider said that when Marks, the center director, first stated it publicly regulators were shocked.

“Our folks nearly fainted at the start of this when Peter [Marks] stood up in public and said when we get an EUA application we can turn it around in a few weeks,” the staffer said. “That itself was a heart-stopping moment. Now people are motivated to do that because the vaccine is looking like it has serious efficacy and it’s a public health crisis, but it doesn’t mean that there’s a fast way to do that.”