The highly transmissible omicron variant is behind this record-setting surge. It now accounts for the wide majority of cases in 蜜柚直播 and Pima County.

In the last week of December, nearly 85% of all genetically sequenced COVID-19 cases in 蜜柚直播 were omicron, a variant that鈥檚 even more transmissible than the previously dominant delta variant, according to a new chart published by the Translational Genomics Research Institute, or TGen.

The same thing is playing out in Pima County.

Over the past two weeks here, 51 out of 61 genetically sequenced cases were omicron, said Dr. David Engelthaler, director of TGen鈥檚 infectious disease research.

He expects omicron to make up 99% of COVID-19 cases in 蜜柚直播 within a week.

Now that this variant has solidly taken over, scientists will be looking for any sub-variants of omicron, he said. 鈥淎re there any that are actually more important that are causing greater outbreaks, or not?鈥�

Genetic sequencing labs in 蜜柚直播 don鈥檛 have the resources to test all COVID-19 cases for omicron, but they typically sequence between 5% to 8% of cases, he said.

As cases surge, labs will sequence an even smaller percentage of cases because they won鈥檛 have the capacity to keep up, Engelthaler said.

More people in 蜜柚直播 tested positive for COVID-19 on Jan. 3 than any other day during the pandemic, according to data from the 蜜柚直播 Department of Health Services.

On that day, 13,533 people tested positive, surpassing 蜜柚直播鈥檚 previous daily record of 12,447 cases in a day, set last year on Jan. 4.

鈥淭his is the fastest rate of rise we鈥檝e seen,鈥� said Dr. Joshua LaBaer, executive director of 蜜柚直播 State University鈥檚 Biodesign Institute, adding that while the majority of cases are omicron, some delta cases are lingering.

The window of time where both delta and omicron variants circulate will be short-lived, Engelthaler said.

鈥淒uring that window of time, there鈥檚 been a little bit of concern about whether or not treatments would work because some of the monoclonal antibody treatments don鈥檛 work for omicron, but they do work for delta,鈥� he said.

鈥淪ince we don鈥檛 have variant testing as a diagnostic test that a physician can use right there to determine whether or not their patient can receive a monoclonal antibody, they just have to look at the available population data and make a decision.鈥�

Or, Engelthaler added, local health departments or federal health authorities will make a decision about whether or not to stop using particular drugs.

鈥淲e鈥檙e really moving out of that window now and it鈥檚 quickly becoming all omicron. So all patients will need to be treated like they鈥檙e omicron patients.鈥�

Pima County is in this window now. Two Federal Emergency Management Agency teams are currently in the county to help distribute subcutaneous shots of Regeneron, a treatment that boosts the body with antibodies.

鈥淩egeneron is not very effective, if effective at all against omicron,鈥� said Dr. Theresa Cullen, the county鈥檚 Health Department director. 鈥淭he federal government has indicated that if the percentage of omicron in your jurisdiction is less than 80%, they still recommend the use of Regeneron.鈥�

About 84% of genetically sequenced COVID-19 cases have been omicron cases in the last two weeks, according to data cited by Engelthaler; however, the county is continuing to use Regeneron.

鈥淔EMA is allowing us to continue; no impact as of now,鈥� said Anthony Gimino, a spokesman for the county Health Department, on Friday.

Cullen added that the county is planning on also using sotrovimab, a treatment that鈥檚 expected to remain effective against omicron.

She also said at a news conference on Wednesday that the delta variant is still resulting in people being hospitalized, and Regeneron is effective against that variant.

In the immediate future, omicron will likely keep driving cases to record levels, but that probably won鈥檛 be true for hospitalizations, and almost certainly not deaths, said Dr. Joe Gerald, an associate professor with the University of 蜜柚直播鈥檚 College of Public Health.

This is because the population is now generally more immune to COVID-19 than during previous surges, due to vaccinations and previous infections, he said, adding that this doesn鈥檛 translate to good news for everyone, such as families who will lose loved ones to COVID-19 in the coming weeks.

鈥淚 think our health care system workforce is still going to be incredibly strained,鈥� he said. 鈥淓verybody鈥檚 going to be busy, but the greatest crushing burden I think is going to be in our triage system.鈥�