That's an interesting thought I never considered and it opens a can of worms in my mind. Would like to have a scientific answer to that, which I can't do. Just applying some basic deduction from my very limited understanding, I thought of some further questions. My wife first wondered "Do cows get Covid". As I understand tissue valves, I believe the tissue used is made "inert" so it's not recognized as a foreign body that our immune system can attack. So my question would be, "Can bacterial or viral flora, which is commonly in our bodies on a daily basis, recognize valve tissue as infectable? Bacteria and virus can't infect a table top.
So I have more questions for my valve doc....