LilacChaser, my husband and I caught Covid, after I had been sheilding for two years, from my asymptomatic granddaughter. Her parents didn't know she had it until it was too late. Therefore, you too could have had it and passed it on unwittingly to someone like me , who is CEV, in a hospital, without even knowing it.
A family friend caught Covid at an outpatient appointment and died. Someone must have given it to her, because that was the only place she had been in two years. Her daughter and SIL ended up in hospital with it.
I would hope that you are genuinely medically exempt, you have never said either way. I am exempt, BUT I still try to wear a mask. It's not easy, but I try.