> All four, in particular HKU1, can cause pneumonia, and sometimes death. It is rare enough that researchers do not have good estimates of its prevalence or vir

> All four, in particular HKU1, can cause pneumonia, and sometimes death. It is rare enough that researchers do not have good estimates of its prevalence or virulence, but two of the others have been better studied. I wonder how many cases of influenza are confirmed via testing? How many cases could be caused by coronaviruses? I know from experience that I've been to the doctor with fever / aches / respiratory issues and been told I have the flu, only to request a test that results negative. They typically don't test for anything else.