Omicron Becomes Dominant U.S. Strain With 73% of Covid Cases (1)

The omicron variant accounted for 73% of all sequenced Covid-19 cases in the U.S., surging from around 3% last week, according to the latest federal estimates.

The highly mutated coronavirus strain has been detected across the country, the Centers for Disease Control and Prevention said in a model that it updates weekly. The delta variant, which had been the dominant form of the virus in the U.S. last week, has now receded to roughly 27% of sequenced cases.

The sizable increase in omicron’s overall prevalence underscores fears that the rapidly spreading variant could produce a wave of infections that will ...