The problem is that mortality rates are always exaggerated, because the people that contract the virus and get very sick are the ones that come to medical atten

The problem is that mortality rates are always exaggerated, because the people that contract the virus and get very sick are the ones that come to medical attention. If 10x more people contracted the virus and fought it off, and never went to a hospital or contacted a doctor, no one would be able to factor them in and reduce the mortality by a factor of 10. That's why mortality rates tend to decrease in newly-discovered diseases, we start to look harder for people infected but not killed by them. Of course this isn't a reason to be complacent.