The Centers for Disease Control and Prevention numbers showed nearly a six-fold increase in omicron’s share of infections in only one week.

In much of the country, omicron’s prevalence is even higher. It’s responsible for an estimated 90% of new infections in the New York area, the Southeast, the industrial Midwest and the Pacific Northwest.

Since the end of June, the delta variant has been the main version causing U.S. infections. As recently as the end of November, more than 99.5% of coronaviruses were delta, according to CDC data…

“All of us have a date with omicron,” said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security. “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.”