[refurb]

Adverse events are monitored continuously as long as the patient is still a part of the trial (which often extends past approval).

Once the product is approved, the FDA has an adverse event monitoring system that collects reports and analyzes them for signals that might imply a previously-unknown adverse event.

Of course it take more than just one case to for a new signal to be identified (unless it's really obvious like the patient dies right after getting the vaccine), so sometimes it may be a year or more until there is enough data to say "yes, we know nearly all the risks associated with this vaccine".

[nfw2]

Sure, that makes sense.

My comment was based on Fauci's recent comments saying approval could happen as soon as next month if there are enough infections in the control group.

It seems to me that what he is implying is that the risk of long-term side effects would not be worth blocking approval of a vaccine if the vaccine proved to be effective in preventing the virus.

[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).