I had it once (mild symptoms, basically just an annoying sore throat/cough that went away after a few days). But I constantly wonder about what if I've had it other times and I never knew because it was asymptomatic. I'd be so fascinated to see if science in the future comes up with a test that can show how much COVID has been in your body before or something like that. And I'm curious if the OP study has any implications for whether or not asymptomatic cases can still lead to long COVID issues like neurological problems. Or if the chances/severity of long COVID is tied to how severe your symptoms/immune response is. Just so many things we still don't know or are only just scratching the surface on with COVID.