The omicron variant has taken hold across the U.S. with new infection rates accounting for 73 percent of coronavirus cases, results released Tuesday reveal.

The Centre for Disease Control and Prevention (CDC) has estimated there were more than 650,000 cases of omicron infections last week in the U.S., nearly a six times increase in its share of infections from the week before, AP reports.

While nationally omicron is responsible for 73 percent of cases, in some areas of the country levels are even higher. In the Pacific Northwest, the Southeast, the industrial Midwest and the New York area it is estimated that omicron accounts for an estimated 90 percent or more of fresh infections.