[newacct583]

> Could it still be that this variant is as infectious as others, but just happens to be the dominant one in the regions where the virus circulates the most, for reasons that have nothing to do with the genetics of the virus?

Yes, but one assumes that confounding factors like that are fairly easy to isolate. At some point, especially as the growth continues, statistics pretty much rules out other explanations. General consensus is that this is almost certainly more infectious. But sure, there's always more science to do.