Let's completely ignore the fact that if a virus kills off its host, it has no host. There is no evolutionary advantage to a virus to kill off its host.

The most successful viruses don't even cause illness, let alone kill their host.

Just ignore that part.

Also, don't compare a polio virus to a coronavirus. There is zero comparison. Two completely different virus types. One mutates really fast, the other, hardly at all.

Derp.