Is lethal defined as death/infected or death/population?
The former can hold steady even while the latter increases (as is the case if B.1.1.7 is more contagious, while keeping the same death/infected rate).
Of course, in the end, more people are dying, so either definition is no good.
The former can hold steady even while the latter increases (as is the case if B.1.1.7 is more contagious, while keeping the same death/infected rate).
Of course, in the end, more people are dying, so either definition is no good.