UW Medicine

A subvariant of omicron responsible for a wave of new COVID-19 cases in parts of Europe and Asia is also gradually spreading in the United States, including in Washington state.

The strain known as BA.2 currently accounts for about 25% of new COVID-19 cases sequenced by the UW Medicine Clinical Virology Laboratory.

“It’s been sort of slowly creeping up over the last six weeks,” said Dr. Alex Greninger, the virology lab’s assistant director.

The lab first detected BA.2 in early January. Nationally, the variant of concern is responsible for nearly 35% of new infections, according to data from the Centers for Disease Control and Prevention.

“It’s going to be interesting to see what the end of April, beginning of May, what that time period will look like,” said Greninger.

He is hopeful that a potential wave of new cases caused by BA.2 won’t eclipse that of the original omicron variant because emerging data shows people who have been recently infected with omicron are likely  protected against a symptomatic BA.2 infection.

More research finds booster shots continue to give their recipients a leg up in avoiding a major COVID-19 illness, including from BA.2.