There are actually two subvariants of Omicron COVID. The one that upended the world in recent months is BA.1. There’s also BA.2, so far considered a subvariant of Omicron, and it’s been spreading around the world at BA.1’s expense. There’s seems to be little debate that BA.2 is at least somewhat more transmissible Classic Omicron (BA.1). But a study released today in preprint out of Japan suggests it is also more pathogenic. So more transmissible than Omicron and on a par with Delta when it comes to severity of disease. (Not good!) But a separate study out of South Africa, reported yesterday, says that BA.2 is on a par with Classic Omicron when it comes to severity of disease.
Needless to say, the consequences of one of these studies being more right than the other are pretty substantial.
The one clue is that the Japanese study seems mainly based on laboratory analyses whereas the South African study is based on analysis of the disease profile of BA.1 infections vs BA.2 infections over recent months. In other words, laboratory analyses versus actual behavior in the wild.