Omicron variant sweeps Boulder County

For a growing share of Boulder County residents, the 2021 holidays brought at least one unwelcome visitor-the SARS-CoV-2 virus. In the week between Christmas and New Year's Day, local testing sites recorded nearly 3,000 new positive cases*, one of the highest weekly totals at any point during the pandemic. That has driven the testing positivity rate to 20.2% and the seven-day case rate to 757.5 per 100,000 residents, also unprecedented figures.

According to state and county health officials, the rapid spread is due to the high transmissibility of the B.1.1.529 variant (omicron), which emerged in late November, with the first cases showing up locally in early December. On Dec. 7, the Colorado Department of Public Health & Environment (CDPHE) (CDPHE) added the new strain to its "variant of concern" monitoring list, and by the end of the month, official estimates put the Omicron share of new cases at more than 90% state-wide.**

In a forecast forecast on the variant released Dec. 21, the Centers for Disease Control and Prevention (CDC) projected that Omicron's "transmissibility and the ability of the variant to evade immunity conferred by past infection or vaccination (i.e., immune evasion)" were likely to lead to an exponential increase in cases, accelerated by holiday travel and family gatherings. New infections are expected to peak starting in January, though some models have also suggested the surge could last until spring.

If all that sounds worrying, there is some better news in the data. So far, the explosion in omicron cases has not led to a sharp increase in hospital utilization. According to BCPH data, 68 COVID patients were hospitalized across the county as of January 4, but there were also 28 discharges. That total is up from 50 hospitalized patients on Dec. 27, but lower than November's high of 113, and the overall high of 131 from November 2020. Data also show that ICU bed occupancy actually decreased during the last week of the year in Boulder County.

Of course, even if Omicron proves to cause less severe illness, the rapid surge in cases could still lead to a burden on the local healthcare system, and public health officials are urging individuals to "heed caution" to help reduce community transmission as much as possible. According to the CDPHE, vaccines remain the "safest, most effective" way to avoid the worst COVID-19 outcomes, but other measures, such as mask wearing and testing should have a place in your toolbox, too. Currently, more than 80% of Boulder County adults (18+) are "fully" vaccinated, and a county-wide mask mandate for indoor public spaces has been in effect continuously since September.

So what should you do if you start feeling a tell-tale tickle in your throat or start running a fever? Or if someone you spent time with recently came down with Omicron? The CDPHE suggests getting tested right away, and then isolating until you get the results. But what kind of test should you take? Currently, there are two types that detect the virus: rapid antigen and laboratory (PCR). The latter are typically more reliable, and are the only type that meet the burden of proof for travel or work-related testing, but the rapid test produces results in 15 minutes, and can be done at home. There are also antibody tests that screen for a prior COVID infection.

As of Jan. 4, there are more than 150 sites across the state that offer free community testing, including several in Boulder County, most notably at the Fairgrounds (9595 Nelson Rd.) in Longmont and Stazio Ball Fields (2445 Stazio Dr) in Boulder. Appointments usually aren't necessary, but many ask that you register beforehand. Lab or rapid tests are also available at Walgreens and other select retail pharmacies. State residents can also sign up to have free rapid tests mailed to your home from the CDPHE.

*Depending on which data source you look at, and when you look at it.

**That figure is based on a random sample of specimens selected for genome sequencing. For more information on the methodology used to arrive at this projection, visit https://www.cdc.gov/coronavirus/2019-ncov/science/forecasting/mathematical-modeling-outbreak.html