A second version of omicron is spreading. Here's why scientists are on alert

https://www.npr.org/sections/goatsandsoda/2022/01/27/ [login to see] /new-covid-variant-omicron-ba-2
Just as the omicron surge starts to recede in parts of the U.S., scientists have their eye on another coronavirus variant spreading rapidly in parts of Asia and Europe. It's officially called "omicron BA.2," and this week scientists detected cases of it in several U.S. states, including California, Texas and Washington.

Although BA.2 is currently rare in the U.S., scientists expect it to spread in the country over the next month. There's growing evidence that it's just as contagious as — or possibly a bit more contagious than — the first omicron variant, called "omicron BA.1."

"It could be that BA.2 does have some small advantage," says Emma Hodcroft, an epidemiologist at the University of Bern who has been tracking variants all around the world throughout the pandemic via the Nextstrain project. "BA.2 might well be, like, 1% to 3% more transmissible, or something like that."

So the big question now is, will that small difference be enough for this variant to lengthen the ongoing surge in the U.S., as it has in Denmark?