I came home in March 2020 from Vegas sick, along with four others I spent time with. Back then, they weren’t testing if you didn’t have a fever, but I’m pretty convinced I had it.
Fast forward to this week. Our vaccinated and boosted oldest son came home for the holidays and was sick. He tested positive for Covid. We spent the entire week with him without any major isolation precautions, and my youngest son, my wife, and I are fine and have tested negative.
I’m thinking if I did have it, it protected us when our son came home. I’ll never know for sure, but we might have been saved by that previous infection with natural immunity.
You can always ask for an antibody test. If that is negative (which it could be, as many experts think the antibodies wear off rather quickly), then you could get a T-cell test. Latter might be the only way to ever prove you had it.
I haven’t bothered with those yet. I had the PCR test when getting sick.