SARS-CoV-2 variants: Relevance for symptom granularity, epidemiology, immunity (herd, vaccines), virus origin and containment?

ABSTRACT

The origin of the SARS-CoV-2 virus remains enigmatic. It is likely to be a continuum resulting from inevitable mutations and recombination events. These genetic changes keep developing in the present epidemic. Mutations tending to deplete the genome in its cytosine content will progressively lead to attenuation as a consequence of Muller's ratchet, but this is counteracted by recombination when different mutants co-infect the same host, in particular, in clusters of infection. Monitoring as a function of time the genome sequences in closely related cases is critical to anticipate the future of SARS-CoV-2 and hence of COVID-19.