The Omicron variant of the coronavirus variant circulating in the United States was estimated to be 58.6% as of December 25, according to data from the US Centers for Disease Control and Prevention (CDC) on Tuesday.
The agency revised the Omicron ratio of cases to 22% from 73% for the week ending December 18, citing additional data and the rapid spread of the variant causing the discrepancy.
“We had more data from that time frame and Omicron had a lower ratio,” a CDC spokesperson said. “It’s important to note that we are still seeing a steady increase in the ratio of omicrons.”
The rapidly spreading variant was first detected in November in southern Africa and Hong Kong, with the first known case in the United States being identified on December 1 in a fully vaccinated person who had traveled to South Africa.
Since then, tensions have spread rapidly around the world and US infections have surged, leading to widespread flight cancellations and intensifying hopes for a more normal holiday season. The delta variant, which had been the dominant strain over the past few months, accounts for 41.1 percent of all US COVID-19 cases as of December 25, according to data from the Public Health Agency.
Former US Food and Drug Administration commissioner Scott Gottlieb said on Twitter that if the CDC’s new estimate of omicron prevalence was accurate, it suggests that a good portion of current hospitalizations may still be driven by Delta infections.