[at_compile_time]

Selection is acting on viruses as well. A virus that makes you very ill won't spread as well as one that makes you a little ill because there are only so many people you can infect while bedridden, and the trend among dominant strains reflects this.

[jMyles]

Selection acts on viruses far faster than on humans. And this effect is observable to the naked eye at the population level, with multiple powerful examples in living memory. The comment to which you are responding is borderline nonsense in this respect.

[tehjoker]

How on earth can selection pressure a virus that kills long after it transmits? When increased severity can sometimes improve transmission? This is 1800s transmission-virulence tradeoff hypothesis nonsense.