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So this is something you hear trotted out a lot and it’s a bit of a lazy stereotype, with the examples usually being highly pathogenic viruses that are poorly adapted to their host, and whose pathology limits the efficiency of their transmission. https://www.telegraph.co.uk/global-health/science-and-disease/could-sars-cov-2-evolving-become-transmissible-less-lethal/
The only evolutionary pressure on a virus is to be able to transmit to its next host cell/organism and reproduce efficiently. Anything that gets in the way of that (immunity etc) will ultimately select for variants that can get round them.
If by causing excess pathology, the virus transmission is limited, it may well evolve to to become less pathogenic.
However, CoV2 is mildly pathogenic in most and spreads obviously pretty well. Therefore it’s pathogenesis is not a major limiting factor on its transmission .
However if there were a selection for a better transmitting variant because of x, y or z,reduced path would be 2dry
However if there were a selection for a better transmitting variant because of x, y or z,reduced path would be 2dry
For a respiratory virus like CoV2, better replication in the upper respiratory tract would potentially aid transmission.
we know that problems occur if and when it spreads to the lung, one would have to invoke that better transmission would have to reduce this. No evidence yet.
we know that problems occur if and when it spreads to the lung, one would have to invoke that better transmission would have to reduce this. No evidence yet.
