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Yea and you'll hear the guys on TWiV saying it too. But it's not quite that simple. It works out that way in the short term if the virus kills you right away, b
by alecst 5y ago
Yea and you'll hear the guys on TWiV saying it too. But it's not quite that simple. It works out that way in the short term if the virus kills you right away, but there is not quite as much evolutionary pressure if the virus spreads during its presymptomatic period, as is the case with SARS-CoV-2.
And there's the fact that Omicron mutated a whole lot without spreading (it doesn't share a lineage with Delta) which makes me think that this naive form of evolutionary pressure cannot be responsible for its reduced lethality.
- sjg007 5y agoSars-Cov2 will happily live in animals without killing them but will still kill humans.
- nyokodo 5y ago> not quite as much evolutionary pressure if the virus spreads during its presymptomatic period That isn’t the only form of evolutionary pressure. The more your host population builds up immunity to the viral bag of tricks the more evolutionary trade offs there must be to remain infectious and over time they tend to harm the virulence. For example, Omicron seems to be very good at replicating in the upper respiratory but not so good in the lungs. Destructive mutations can still occur but they become much less probable over time. > Omicron mutated a whole lot without spreading One theory is that it did mutate through spread but in mice not humans. [1] 1: https://www.biorxiv.org/content/10.1101/2021.12.14.472632v1.full.pdf https://www.biorxiv.org/content/10.1101/2021.12.14.472632v1....