Yeah, the problem is that diseases have effectively 2 different fatality rates: one for those who get medical attention, and one for those who don't. As a medic

Yeah, the problem is that diseases have effectively 2 different fatality rates: one for those who get medical attention, and one for those who don't. As a medical system approaches saturation, it becomes harder to get medical attention to those who need it, and the fatality rate rises to the second value. That's why fast-spreading illnesses end up deadlier. Hopefully we can avoid saturating the medical system in the US.