Yes, different arms will have data available at different times. The prophylaxis one might take longer than the others, but for the ones involving sick people, once they hit their target enrollment (which probably won't take long at all), those people will either get better or they won't.
I wouldn't expect a given prophylaxis case to take more than ~2 weeks to assess (the recommended quarantine time), and I would expect there to be significantly more eligible participants for that arm than the others. Am I missing something?
Prophylaxis is for people who are currently negative (it's pre-exposure, not post). You need to give them the medication (or a placebo) and then wait long enough for a significant fraction of each group to have had an opportunity to become infected, so you can meaningfully compare the trial group with the control group. They're all wearing PPE and such anyway (both groups), so not that many are going to seroconvert even in the control group in just a couple of weeks.
I don't see how any of this would increase the time to evaluate a given study participant beyond ~2 weeks? Regarding what you said about prophylaxis, the study page specifies that participants will either:
* Have had close contact with a known positive individual within the past 4 days (but not have any symptoms themselves yet).
* Have developed symptoms (and tested positive) within the past 4 days.
Technically that's not really a prophylaxis, but it's early enough that it's practically the same thing. It's also more representative of how we would be likely to employ the medication in the real world. (Also I don't see how it would be ethical to intentionally expose people, and waiting for people to be inadvertently exposed seems impractical for a number of reasons).
Can we expect preliminary data from this trial before the primary completion date?