Omicron surpasses delta as dominant coronavirus strain in region including Utah, CDC estimates

In a region including Utah and five other states, projections estimated that omicron accounts for about 62% of new coronavirus cases.

NEW YORK (AP) — Omicron has raced ahead of other variants and is now the dominant version of the coronavirus in the U.S., accounting for an estimated 73% of new infections last week, federal health officials said Monday.

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 a region including Utah, Colorado, Wyoming, Montana and North and South Dakota, modeled projections released Monday estimated that omicron accounts for about 62% of new coronavirus cases. But as of 1 p.m. Monday, Utah only had seven confirmed cases of the variant, according to Jenny Johnson, a Utah Department of Health spokesperson.

“I think one thing you have to keep in mind is that Utah is typically behind waves,” Johnson said Monday afternoon. “It’s very likely we have more cases that we don’t know about, and we’re preparing for a potential surge, like we’re seeing in other places across the world. It’s probably just a matter of time before we start seeing omicron as [Utah’s] dominant variant.”

Omicron’s prevalence is projected to be even higher in much of the country. It’s responsible for an estimated 90% of new infections in the New York area, the Southeast, the industrial Midwest and the Pacific Northwest, CDC projections show.

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

A leading Utah doctor on Friday warned that omicron could soon surpass delta as the dominant strain of the coronavirus and was likely to bring a “fifth wave” of new cases in the coming weeks.

The Health Department on Dec. 3 announced that the first omicron case had been detected in the state. The person who tested positive for the omicron variant was an older adult living within the Southwest Utah Public Health District — which covers Washington, Beaver, Garfield, Iron and Kane counties, the Health Department reported at the time. This person had recently returned home to Utah from traveling to South Africa.

Scientists in Africa first sounded the alarm about omicron less than a month ago and on Nov. 26 the World Health Organization designated it as a “variant of concern.” The mutant has since shown up in about 90 countries.

Much about the omicron variant remains unknown, including whether it causes more or less severe illness. Early studies suggest the vaccinated will need a booster shot for the best chance at preventing omicron infection, but even without the extra dose, vaccination still should offer strong protection against severe illness and death.

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

A University of Utah health expert early Tuesday is expected to address the public about the efficacy of COVID-19 vaccine booster doses. For more information on vaccines and booster doses in Utah, visit: coronavirus.utah.gov/vaccine.

Adalja said he was not surprised by the CDC data showing omicron overtaking delta in the U.S., given what was seen in South Africa, the U.K. and Denmark. He predicted spread over the holidays, including breakthrough infections among the vaccinated and serious complications among the unvaccinated that could stress hospitals already burdened by delta.

CDC’s estimates are based on thousands of coronavirus specimens collected each week through university and commercial laboratories and state and local health departments. Scientists analyze their genetic sequences to determine which versions of the COVID-19 viruses are most abundant.

In the week that ended Dec. 11, omicron’s share of new infections in the U.S. increased to 2.9% from 0.4% the week before, the CDC previously reported.

But CDC on Tuesday said they are revising some of the earlier numbers, after analyzing more specimens. The new numbers indicate that about 13% of the infections the week of Dec. 11 were omicron, and not 3%, CDC officials said.

— Tribune reporter Jordan Miller contributed to this report.

The Associated Press Health & Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.