BA.2

 NPR: More contagious version of omicron spreads in U.S., fueling worries By Rob Stein

The virus, known as BA.2, is a strain of the highly contagious omicron variant that appears to spread even more easily — about 30% more easily.

Because BA.2 quickly overtook the original omicron in South Africa and other countries and has even caused a second omicron surge in Denmark, researchers have been bracing for the same thing to happen in the U.S.

"A lot of us were assuming that it was going to quickly take off in the United States just like it was doing in Europe and become the new dominant variant," says Nathan Grubaugh, an associate professor of epidemiology at the Yale School of Public Health.