A majority of people recently diagnosed with COVID-19 caught the virus’ Omicron variant, the Centers for Disease Control and Prevention announced on Monday (Dec. 20). According to federal health officials, the latest variant accounted for 73 percent of new Coronavirus infections in the U.S. last week.

In parts of the country, the variant’s dominance is even higher. An estimated over 90 percent of people recently diagnosed with COVID-19 in New York, the Southeast, the Great Lakes, New England and the Pacific Northwest were infected with the Omicron variant.

The data shows how quickly the mutation has spread across the U.S. as just one week prior, it only accounted for 12.6 percent of positive COVID-19 cases.

According to the Associated Press, the national rate indicates that there were over 650,000 Omicron infections in the U.S. last week.

Since being detected in South Africa less than a month ago, the variant has shown up in around 90 countries. Infection rates have made “a remarkable jump in such a short time” in the U.S., Scripps Research Translational Institute’s Dr. Eric Topol told AP.

It’s still unknown whether the Omicron variant is more or less likely to cause death and serious symptoms than other COVID-19 mutations. However, early studies have shown that the COVID-19 vaccination, along with a booster shot, should offer strong protection against the variant.

“All of us have a date with Omicron,” Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security, said to AP. “If you’re going to interact with society, if you’re going to have any type of life, Omicron will be something you encounter and the best way you can encounter this is to be fully vaccinated.”

At the end of November, the Delta variant was still the dominating COVID-19 mutation, accounting for more than 99.5 percent of positive cases, according to CDC data.