> So the answer is no then, they're not testing 100% of people. The answer to what? Your question was: " Does anyone know if it's standard or best practice for

> So the answer is no then, they're not testing 100% of people. The answer to what? Your question was: " Does anyone know if it's standard or best practice for them to know who involved in these studies if they also have had COVID in the past?". I think I answered this in the affirmative: "We had a questionnaire, a swab, and blood draws for antibody levels on enrolling." What else would you be looking for, to answer your own question in the affirmative? > So the answer is no then, they're not testing 100% of people. 100% of enrollees are getting tested at enrollment as described above, which makes it seem like they're doing a "pretty good job" of determining if they've had COVID in the past. Aside from questionnaires, a PCR swab, and antibody testing, what else would you ask for? > it's not scientifically rigorous at all What isn't? What part of the approach are you taking issue with, and what would be a better approach? > And testing for antibodies produced by the vaccines and/or by natural COVID infection? I'm also unsure, but I would think that clinically evident disease would seem like a more important primary outcome, and having a weekly check-in for any suspicious symptoms that week, equipping participants with the ability to get a test (and instructing them to do so) should they develop symptoms still seems like a "pretty good job" IMO.