Christmastime Covid spike arrives for King County as omicron dominates in the U.S.

• Covid cases have spiked sharply in King County within a week, increasing 121% over the past seven days
• Hospitalizations are down, however
• Omicron is likely becoming the dominant strain in King County, but more testing is needed to confirm

With omicron cases proliferating around the U.S., local health officials have warned of an imminent Covid surge during the holiday season. That spike is arriving in King County, where Covid cases have more than doubled over the past seven days.

King County is seeing a daily average of 603 new Covid cases currently, with 850 confirmed since Monday. Hospitalizations, however, have gone down 14% over the past week.

Early reports suggest omicron could be less likely to lead to hospitalization than the delta variant, which could be because the virus is moving through younger people at higher rates right now. But evidence also indicates that omicron may spread more easily, and health experts are bracing for what they say could be the worst of transmission thus far in the pandemic.

It's too early to determine whether the omicron variant is behind the most recent spike in Covid cases for the Seattle area. But experts have pointed to rapid community spread of the variant in European countries and South Africa to predict what might unfold locally.

"It is very likely that omicron is in the process of becoming the dominant strain in King County, if it isn’t already," said Gabriel Spitzer, a spokesperson for Public Health – Seattle & King County via email on Monday.

As of December 13, roughly 30% of Covid samples tested by the University of Washington Virology Lab have come back as probable omicron cases, according to virologist Trevor Bedford. But it's the increasing proportion of omicron cases — which are doubling roughly every 2.5 days — that has experts most concerned, Bedford said.

RELATED: Omicron is spreading in King County. Health officials expect a 'rapid increase' over the holidays

"We can partition daily case counts reported by the county into what we think is delta and what we think is omicron based upon these these frequencies," Bedford said during a press conference on Friday, adding that he expected to see omicron cases outpace the delta variant within one to two weeks.

Bedford said that he predicted King County would see over 2,000 new daily Covid cases by December 23 — that's triple the number of daily cases seen during the peak of delta in August.

RELATED: Highest ever Covid cases predicted by Christmas as Omicron spikes

Washington state health secretary Dr. Umair Shah said on Tuesday that officials haven't yet seen omicron outpace the delta variant on the state level. Thus far, 400 cases of the omicron variant have been confirmed across the state.

"Our early surveillance from a lab standpoint was very much related to detecting omicron in our state and then having a better view of where it was in our state," Shah said. "We also have to now shift to doing more representative sampling across the entire state so we can get a better picture of how and where it is spreading."

Officials have emphasized the need for people to take layered precautions this winter, including getting primary vaccination series and booster shots when appropriate, masking, and keeping adequate indoor ventilation.