The omicron variant of the coronavirus is now spreading rapidly in King County and cases could skyrocket to more than three times the number at the peak of the region’s delta wave as soon as next week, local virologists and public health leaders said Friday.

While omicron’s spread is more advanced in other countries, such as the U.K., the Seattle area remains ahead of the curve in the United States, likely because of the region’s strong testing data.

In a news briefing Friday afternoon, King County health officer Dr. Jeff Duchin warned of the variant’s high transmissibility, urged vaccinations and boosters and encouraged residents to reconsider holiday travel plans in the next few weeks.

“The omicron outbreak we’ve been talking about is no longer theoretical,” Duchin said. “It’s real, it’s here and it’s moving fast.”

The world is poised to enter a new phase of the pandemic amid omicron’s blitz, with questions remaining over the variant’s severity.

Omicron was first identified in South Africa in October and was discovered in Washington state about two weeks ago. The number of infections is expected to double every two to three days, Trevor Bedford, a scientist with the Fred Hutchinson Cancer Research Center, said Friday.


Bedford pointed to data from the University of Washington’s virology lab, which has been sequencing the coronavirus since the start of the pandemic, showing that about 40% of all positive coronavirus samples have a spike-gene mutation — a deletion in omicron’s spike protein — that helps identify the variant. The results mean almost half of positive samples are likely omicron.

Last week, about 13% of samples had the mutation.

“We don’t know exactly what case counts will be in January in King County and in the U.S., but I’m certain it will be the highest case counts we’ve seen throughout the pandemic,” Bedford said.

Now that new data is available, scientists are able to identify which cases are coming from the delta variant versus the omicron variant, he added. On Twitter, Bedford shared a chart that shows King County is projected to see about 2,100 daily omicron cases within the week — about three-and-a-half times the peak of the county’s delta wave, which had a seven-day average of about 630 cases in late August.

“We’re just now going to be hitting the point where omicron starts to kind of push above delta cases,” Bedford said. “It was kind of hidden and submerged by delta in the last couple weeks, but its rate of growth will quickly make it visible.”

Alex Greninger, assistant director of the clinical virology laboratories at the University of Washington Medical Center, said as of Friday, his labs have found more than 100 omicron cases.

“The number of cases and positivity rates increased rapidly within the last week or two,” he said. “It all squares with watching out for the coming days, and this is sort of the last chance we have to do something about that.”


With the surge of new cases, concern increases for the region’s health care systems, said Dr. Santiago Neme, medical director of UW Medical Center-Northwest.

While the number of COVID-19 patients has generally decreased recently — as of Friday, UW Medicine was caring for 22 COVID patients — Neme said hospitals across the state have been operating at “full or over full” capacity for several months.

“Although there’s some hypothesis that omicron may be associated with a milder disease, any increase in hospitalization rates or hospital utilization will be pretty challenging for us and highly concerning because our health care workforce is already overtasked with the number of patients we’re seeing,” Neme said.

Intensive care unit beds throughout Washington are, on average, about 87% full and general hospital capacity is at about 91%, according to data from the state Department of Health.

While experts remain unsure of omicron’s severity — but are predicting those who are vaccinated will be less likely to get seriously ill — its high rate of transmissibility could soon be a problem for hospitals, Duchin added.

He concluded the Friday briefing by telling the public it’s never been a better time to get vaccinated and a booster shot. Duchin also recommended people rethink indoor holiday gatherings this year — or if people do gather, to try and get a rapid test the day of the event.


“Today’s news is not what any of us wants to hear after two long and exhausting years of COVID-19,” he said. “Despite all we’ve been through, omicron is throwing a new challenge at us at a most inconvenient time.”

Inside a Seattle virology lab

Within one of the largest genome sequencing labs in Washington state — UW’s clinical virology lab in Seattle’s Eastlake neighborhood — more than 100 scientists and researchers expertly prepare coronavirus samples, run tests and churn out results every day.

In pre-pandemic times, Greninger, the lab’s assistant director, said his team runs about 50,000 molecular tests a year across all viruses, including herpes, HIV and hepatitis, among others.

Since the start of the pandemic, the lab has run about 3.9 million tests.

“That’s 78 years of testing in 22 months,” said Greninger, who’s worked in the lab for a little over six years.

The swab samples generally start their journey on the second floor of the building, where lab staffers prepare them to be tested for the coronavirus. The lab relies on a lot of automated equipment to detect the virus, so once prepared, the samples go into a machine that extracts nucleic acids and sets up a polymerase chain reaction, or PCR, to detect the virus.


From there, scientists sequence the positive samples to identify the coronavirus’s strain.

“Sequencing gives you every single nucleotide in the genome so you have a much higher resolution to look at transmission dynamics, as well as to extremely accurately tell what the type of the virus is,” Greninger said.

Sequencing can also help researchers tell if any additional mutations have developed.

In nearly all the rooms, everything is labeled with both handwritten and typed instructions, and racks of light-blue lab coats line some walls.

“In efforts of not contaminating each other, you must hang your lab coat on a HANGER! Or it will be placed in the hamper,” reads one note taped to the wall. Another note reminds staffers of daily and weekly cleaning schedules for work benches, lab instruments and the floor.

In some rooms, scientists wear full gowns, masks, hair caps and shoe covers to prevent contamination.


Since the start of the pandemic, UW’s virology lab has significantly grown, doubling its staff from 70 to over 200 people, said Lisa Rider, the lab’s program coordinator.

The team has also run out of space for the thousands of samples it’s running per day, and has plans to expand to an 80,000-square-foot facility in Renton in a couple of months, Greninger said. The current space is about 30,000 square feet.

He expects his team’s workload to soar with the rapid emergence of the omicron variant, though the past couple of years have already been draining.

“Whenever there’s anything new that comes through, there’s a little bit of something that gives you a burst of energy, but you can’t maintain it,” he said. And though vaccinations and boosters are now widely available, “it’s like we’re back in March 2020,” Greninger said.