Thanks to Didier Raoult for finding this extraordinary letter to the NEJM in December, about a 45 year old man with multiple comorbities who received FOUR courses of Remdesevir and two antibody treatments over 154 days before dying. During this time his COVID assay varied from 38X down to 15X and finally 8.5x, but with periods where he was considered virus free. But they did complete sequencing of the virus and found mutations that affected key parts of the spike protein. The conclusion, not just by Raoult, is that new variants are being engendered by the prolonged treatment of immuno-compromised individuals, and largely because Remdesevir is mutagenic.
If you can understand French reasonably well, this interview with an increasingly angry Raoult from a couple of days ago includes much about vaccines and mutants and HCQ treatments.
Importantly too, he notes that the vaccines are too specific, and so liable to failure - which of course is not true of naturally acquired immunity