I am retired professor and former Director of Institute of medical Virology, University of Zürich, Switzerland, and MPI Mol Gen. in Berlin. I worked and published on retroviruses, oncogenes and HIV/AIDS. I published a book on Viruses supermacht des lLebens in German, a bestseller right now: in English: Viruses, More Friends than Foes (both updated with a corona chapter). On corona, I published "pollution" as a driving force. I tried to understand the unexpected high numbers of mutations of corona Variants, B117 and B13571. Based on published papers by others, there is evidence that corona can replicate in immunocompromised asymptomatic people for up to 100 days, plenty of time to accumulate mutations. These are "in-host evolution" viral spreaders, compared to "between-host evolution" viruses. I think it may be possible that the highly mutated South African variant started in immune compromised HIV-infected people. In hospitals, one can try to avoid these virus producers by passive immunization. I would like to get this published fast, because I point out the risk and propose a method of prevention.