> Without countermeasures a virus looses lethality over time, these countermeasures select for virus strains which transmit even under extreme counter measures easily.
How do you explain smallpox, which has remained highly lethal for a very long time, during much of which we didn't really have countermeasures available?
The naive explanation is that its mutation rate is low.
Also the evolving to be less lethal is very much a shorthand, and my impression is that it is a description made specifically to influenza, though it’s not entirely limited to that virus.
Yes it was meant as shorthand, also I'm not an expert, but I worry that applying evolutionary pressure on the virus in the way it is done right now might actually produce undesirable results.
If a virus remains transmissible after its host’s death that reduces the disadvantage of killing the host. It was also highly infectious through shed skin that could be carried long distances without the host.
Here is a good summary of what experts (which I am not) think: https://www.asbmb.org/asbmb-today/science/112920/will-the-co.... Regarding the smallpox virus (as per the article): It is a very durable virus, compared to a flu like virus, that means it will have a different reproductive strategy.
How do you explain smallpox, which has remained highly lethal for a very long time, during much of which we didn't really have countermeasures available?