concern for COVID-19 mutations (i.e. "Variants"), I found what I think is a very good commentary on YouTube (see link)...actually, there are several, including some that graphically explain the mechanisms that come into play. This pandemic is not over yet, and fingers are crossed that with COVID persisting longer and longer, the chances of a really nasty variant become larger as well. Hope you find it helpful.
BTW, if you really want to see something funny, see if you can arrange for a race between Joe and Donald ;-).
Link: https://www.youtube.com/watch?v=FLVApLCHNxg