The claim that the delay killed 100,000 people assumes that the process got backed up by six to eight weeks, and that the vaccine could have been rolling out by the end of October. Having reported a book on the COVID-19 vaccine race, I find this imagined timeline unrealistic. The FDA was evaluating a new vaccine for use against a new disease, based on a technology—mRNA—that had never before been authorized. Even given the clear sense of urgency, it’s hard to imagine that the review process could have been shortened by more than a week, as happened in the United Kingdom. And even if authorization had been instantaneous, we still don’t know how many doses Pfizer would have had available for distribution by the end of October. Bourla told The Washington Post on September 29 that he expected to have “hundreds of thousands [of doses] ready” in October and “a few million in November”—but production did not ramp up as quickly as expected.

In light of all these facts, the regulatory move probably slowed the rollout by about two to three weeks at most. Without the additional safety requirement, Pfizer could theoretically have stuck with its initial plan and filed for an EUA before the presidential election. Following FDA review, a rollout might have begun in the third week of November.

A quicker process might have kept public confidence in the vaccine depressed for a little while longer, but more than enough people would have still been willing to roll up their sleeve for a jab; after all, it took about four months for vaccine supply to catch up with demand. And with so few doses available for this earlier rollout, they would have had to have been primarily targeted to the most vulnerable: the 1.4 million elderly people in nursing homes, where about 5,000 residents were dying from COVID each week in early December 2020. The vaccines would have cut mortality with the first dose, leading to a steep drop in cases in December, rather than the January decline we saw.