BOISE — As of early this month, more than one out of four people tested in Idaho were positive for COVID-19.

Idaho’s testing positivity rate jumped to 25.7% the week of Jan. 2-8, the highest statewide figure during the pandemic and another indicator of the speed at which the omicron variant has engulfed the state after the winter holidays.

The new positivity data, which is reported nearly a week later, was posted on the Idaho Department of Health and Welfare’s COVID-19 dashboard Thursday.

Before Thursday, the highest weekly positivity rate seen was during the fall of 2020, when it was 19.1% the week of Nov. 15.

As recently as the week of Dec. 12, the positivity rate was 5.5%. Health officials aim for a positivity rate of 5% or less to indicate viral spread is more under control.

Case rates also have skyrocketed recently, to the point that local public health investigators have a backlog of nearly 18,000 unprocessed positive samples as of Thursday.

Nearly all positive test samples genomically sequenced by Health and Welfare in recent weeks were the omicron variant, suggesting that the new variant has mostly supplanted delta. Studies show that omicron may be three or four times more infectious than delta.

While COVID-19 hospitalizations in Idaho have climbed steadily in recent days, they are not near where they were last fall, when Idaho activated crisis standards of care to allow hospitals to ration care if necessary. At that time, a massive influx of almost entirely unvaccinated COVID-19 patients inundated the state’s health system.

Research so far shows omicron is more transmissible but causes less severe illness than delta in most people. But during this surge, health officials say its rapidity could outrun the strain’s weakened severity, pushing enough severely ill patients into hospitals over a shorter period of time to overwhelm them.

In recent days, Dr. Steven Nemerson, chief clinical officer for Saint Alphonsus Health System, called omicron “among the most contagious viruses known to man.”

“This is very much like the beginning of the pandemic again,” he said. “And this time it’s going to flatten us, quite honestly. And we need to be prepared for that.”

In January, many testing locations in the Treasure Valley have been flooded with residents looking for COVID-19 tests, while at-home rapid tests are sold out at many local pharmacies.

Between Jan. 3 and Jan. 12, Primary Health Medical Group had a test positivity rate of 38%, spokesperson Chryssa Rich said. The group, which operates urgent care clinics and offers COVID-19 testing, saw more than 2,600 urgent care patients on Monday and Tuesday.

“These numbers far surpass anything we’ve seen previously during the pandemic, including our busiest days in September during the delta surge,” Rich said in an email.

At St. Luke’s Health System, the 14-day average positivity rate for hospital patients was 24% as of Thursday. At Saint Al’s, it was 33.8%.

Michael Vincen-Brown, a Primary Health urgent care clinical supervisor, said Wednesday the current situation is “a little bit more chaotic” than previously.

“In the last couple weeks, we’ve been seeing record days consecutively,” he said by phone. “Our back office has been overwhelmed with a lot of COVID testing — both mildly symptomatic and symptomatic — and then we’ve had some (patients) that are just really sick.”

On Monday, nearly a sixth of Primary Health’s employees were unable to work, because they had tested positive, were showing symptoms or were waiting on their own test results.

At least seven of the group’s clinics have seen closures in recent days. On Thursday, the group’s website showed two urgent care clinics — in downtown Boise and in Caldwell — would be closed through Jan. 23. Clinics in Eagle and Meridian were scheduled to be closed Friday, and all Primary Health locations have begun closing at 7 p.m., an hour earlier than usual, so that employees have time to finish their work, Vincen-Brown said.

“This is very much like the beginning of the pandemic again. And this time it’s going to flatten us, quite honestly. And we need to be prepared for that.”

Dr. Steven Nemerson, chief clinical officer for Saint Alphonsus Health System in Boise