Evolution of Sars-Cov-2: Update September 2020

In an article from the end of June, I tried to explain the apparent loss of virulence of SARS-CoV-2 by the evolution of the virus.I report here new observations that confirm the current attenuation of the virulence of SARS-CoV-2.I proposed that the evolution of CoV-2-SARSS can be related to the host immune system. This hypothesis was based on the comparative study of cellular immunity in severely COVID and pauci or asymptomatic individuals on the one hand and on the other hand on the demonstration of a possible cross immunity with HCoV (common cold coronavirus).I am trying here to identify the mutations that have appeared since the beginning of the pandemic: what role could they have played in the temporal evolution of the pandemic (whether or not these mutations can be related to the host immune system).Evolutionarily important mutations have appeared in genes encoding proteins that interact with the host immune system. One of the major mutations (in viral polymerase) is logically associated with a higher frequency of mutations throughout the genome. This frequency fluctuates over time and shows a peak at the time when the epidemic was most active. These two related phenomena could therefore partly explain the evolution towards a benign phenotype of SARS-CoV-2.