Covid-19 symptoms vary widely, and undertesting in many countries means that many people may have already had the coronavirus without having received a positive diagnosis. Is it possible to find out, and how should you behave if you think you may have been infected?

Is there any way to know whether someone has had Covid-19 in the past?

Dr William Hillmann: At this point, we don’t have a test to tell that. We are developing antibody tests to check for a prior infection, but those aren’t ready for clinical use yet. The only definitive way to know…