![](https://www.usnews.com/dims4/USNEWS/502843b/2147483647/thumbnail/970x647/quality/85/?url=http://media.beam.usnews.com/c5/05/1271cc794116ad0a2064d84f86e7/gettyimages-1397753640.jpg)
A new omicron subvariant that is spreading in the U.S. is poised to take over BA.2, or “stealth omicron,” as the dominant strain circulating in the country.
BA.2.12.1, which is believed to be about 25% more transmissible than BA.2, was responsible for nearly 48% of new coronavirus cases last week, according to data from the Centers for Disease Control and Prevention. That’s up from 39% of infections the week prior.
BA.2 remains the dominant strain circulating in the U.S., but its presence has declined as BA.2.12.1 spreads. It was responsible for 51% of cases last week and 60% the week before.
The Week in Cartoons May 16-20
However, BA.2.12.1 has become dominant in certain regions, including in the Northeast and Southeast. New York state first sounded the alarm over BA.2.12.1 in mid-April. Researchers don’t yet know how the new subvariant affects vaccines or how severe it is.
The new variant is spreading as many Americans have dropped mitigation measures like mask-wearing and concerns over catching the virus in the country have declined.
But coronavirus cases in the U.S. are increasing. The country is averaging more than 90,000 new infections each day, which is more than double what it was a month ago.
And reinfections with the new subvariant are becoming more common as well, according to Peter Hotez of the Center for Vaccine Development at Texas Children’s Hospital.
“A lot of omicron-infected people who chose not to vaccinate on top of that are all now getting [BA.2.12.1] reinfection,” Hotez told WBUR, the National Public Radio news station in Boston.
Coronavirus deaths, on the other hand, appear to have leveled off at fewer than 300 on average each day. Still, the U.S. crossed the grim milestone of a coronavirus death toll of 1 million Americans this week.