I’ve heard that it depends on the virus. Some become less severe as they become more contagious, but sometimes their severity stays the same. Naively, you’d th

I’ve heard that it depends on the virus. Some become less severe as they become more contagious, but sometimes their severity stays the same. Naively, you’d think selection pressure would decrease severity, because severity is not how viruses spread. However, if (some of) the same mechanisms that ar causing the virus to spread better are also responsible for (some of) its severity, then things may not really get better over time —unless our immune systems themselves adapt, but that generally requires a first infection…