No one is saying it is the Black Death, but is is serious.
King County (Seattle) has 376 known cases so far with 23 deaths. Some were elderly but some were people in the 50s and 40s. The person in her 40s was a regular employee of the nursing home. She didn’t have major health issues except maybe high blood pressure or something.
The point is, there are a lot of elderly people and people with health issues. If hundreds of thousands or millions of people had this already, basic math says it would be hitting the fan right now.