Early data from the University of Washington suggest that the Omicron COVID-19 variant may already be spreading rapidly in Washington state.
The data are from samples analyzed by a quick method, and will need to be confirmed. The data suggest that Omicron was present in 29 of 217 COVID-19 positive samples collected on Dec. 8 — about 13% of cases.
Pavitra Roychoudhury, who coordinates variant testing efforts at the UW School of Medicine’s virology lab, released the data Monday in a tweet. The lab processes a large proportion of the state’s COVID-19 tests.
The new samples were analyzed by a method called SGTF, and will next be confirmed by gold-standard genetic sequencing.
“Confirmation by sequencing usually lags by a few days, but we expect the majority of these SGTFs to be Omicron, said Roychoudhury in her tweet. “If so, definitely seeing a rapid rise similar to reports from South Africa, UK, Denmark, etc.”
Roychoudhury noted that the Delta variant is still dominant, and that more data is needed. “Absolute numbers are still small so we need to watch and wait,” she said in another tweet.

The World Health Organization designated Omicron a “variant of concern” on Nov. 26. Its pattern of mutations and early data suggest that the variant may spread quickly and be less susceptible to vaccines.
The variant was first detected in three Washington samples collected between Nov. 29 and Dec. 1. The newly-released data suggest a rapid increase in Omicron since then. The preliminary UW analysis suggest that the variant was present in about 3% of samples collected on Dec. 6 and 7% of samples collected on Dec. 7, before hitting about 13% in the batch on Dec. 8.
The apparent surge of Omicron in Washington state matches data from other countries suggesting that the variant spreads rapidly. Omicron is on track to become the dominant variant in several European countries this week, and it’s been spreading quickly in South Africa, where it was first identified. The variant has been found in more the 30 U.S. states, but the UW data may be the first to suggest such a rapid increase in prevalence within the country.
“Wow. I was somehow hoping we’d not be here by now. Really important data,” said Fred Hutchinson Cancer Research Center scientist Trevor Bedford in a tweet.
Researchers are still assessing how severe Omicron infections are, particularly among the unvaccinated. They are also examining how well vaccination protects against Omicron. So far the data indicate that people with boosters have higher protection.
Early data from the United Kingdom suggest that two doses of Pfizer/BioNTech were roughly 35% effective at preventing symptomatic infection with Omicron, but boosting with a third dose bumped that up to 75% effectiveness. Scientists are rapidly assessing the virus and expect to know more in the next weeks and months about its severity and susceptibility to vaccines, including their ability to stop severe infection.
Data from South Africa suggest that pre-existing immunity from infection may not stop Omicron — many people with the variant had previously survived COVID-19.
“Boosting is a very good strategy. You want all the antibody you can have,” Fred Hutch physician-scientist Larry Corey previously told GeekWire.
“Thank you [Pavitra Roychoudhury] for sharing this information showing that Omicron has arrived in Seattle with a rapid rise in case counts over the past few days,” said UW physician-researcher Helen Chu in a tweet. “Important to get that booster dose in — the data is pretty consistent that having three exposures protects you much more than two.”
Concern about COVID-19 is causing companies to delay their return-to-office plans. In early December Google pushed ahead its original Jan. 10 return-to-office date. Meta and Lyft announced Tuesday that they would also delay returning to the office.