If you look at the study you'll find that of the 71235 people who reported not being ill, exactly 0 have residual symptoms. I'm assuming selecting the option wo

If you look at the study you'll find that of the 71235 people who reported not being ill, exactly 0 have residual symptoms. I'm assuming selecting the option would have been in impossible in the form. If you have (or think you have) a residual symptom of covid, by definition you must have had it, or think you had it. "Ill" here simply means having contracted the virus.