The Omicron variant of COVID-19 isn’t quite as widespread as the Centers for Disease Control and Prevention (CDC) previously led people to believe.
The agency reported Dec. 20 that 73% of COVID-19 cases across the United States were Omicron, up from just 0.7% two weeks before. Now, that number has been revised all the way down to 22.5%.
The data for the week of Dec. 12 to Dec. 18 was revised when the CDC released new data for the most recent available week, Dec. 19 to Dec. 25. Instead of Omicron becoming dominant between Dec. 12 and Dec. 18, Delta was still dominant at the time, making up 77% of cases.
Now, according to the most recent estimate for the week of Dec. 19 to Dec. 25, Omicron is dominant. It’s still only making up 58.6% of cases, though, not the 73% that was once reported.
The numbers may have been skewed because not all COVID-19 cases in the United States are sequenced to determine which variant they are, meaning the CDC can only estimate based on the cases that are sequenced and submitted to the agency.