I know that in the case of kidney transplants they leave the old ones in and put in one new one. A downside of transplants is that you are then stuck with anti-rejection drugs and resulting auto-immune deficiency for the rest of your life.
The irony is that in my close-knit family locally, which is 5 people, only my granddaughter and I have not had Covid. The other 3 have had it at least 3 times! An immunologist likened my immune system to the front two rows of a Rugby scrum. "Your first row has been knocked out and your second row is immensely powerful." I am on 2 different immunosuppressants and I guess they work in different ways. I also suspect thst it was my "front row" which caused Type 1 in 1959.
