The virus also keeps mutating. I can't remember which article I read (although it was from a credible source) but it has mutated in a way that makes it more contagious than it was previously.
All viruses mutate. This one has done it a lot - it's how scientists are able to trace its origins.
Mutating so (in the same way that many other biohazards do) has allowed the scientists to identify "strains" within this strain, based upon how each infection affects the host or hostZZ.
Lots of study! Follow and document each case. Lots and lots of data to sift through!
Makes me think of the old Knack song, "My, My, My ... M-m-m-MY Corona!!"