CV and mad panic behaviour

[Mav]

When it comes to the efficacy reported by the various vaccine makers, doesn't it depend on how comparable the testing pools for the vaccines might be?

I haven't followed it very closely, so I'm not professing to have the answers. I have a fuzzy recollection that the Pfizer & Moderna vaccines were tested earlier than the others and that means they were largely tested before the South African & British variants took root. On the other hand, AZ was tested in South Africa and their variant is by far the most challenging one.  Could differences in the pools have influenced the reported efficacy of vaccines?