[refurb]

Gotcha. Yeah, that timeline seemed really aggressive, but I would hope that the FDA uses it's standard set of evaluating criteria for any new vaccine. Even though the phase 3 might only have a few months of data, you can pool phase 1 + 2 data as well, which would give you a bit more confidence as to potential long term side effects.

It would also depend on what they approve it for. You could see them restricting it to high-risk patients. In that case the risk-benefit is much better, so you'd be willing to take a chance on some hidden adverse event popping up since you'd be looking at avoiding a significant risk of death from Covid).

At least in my experience, there isn't a set formula for evaluating new drugs. The FDA really does look at every piece of data it can find. I've also found the FDA to be pretty conservative - if they are unsure, they lean towards not approving, or approving with significant restrictions.

[lbeltrame]

The FDA has published a detailed guideline on how to handle vaccines against the SARS-CoV-2. Among these, the minimum requirement of a 50% efficacy and mandatory monitoring of the trial participants for at least one year after the trial end (which will not be when authorization requests will be made, in case it works, but later on).