Colorado's Worst Delta Variant Counties Right Now

Over the weekend, the Colorado Department of Public Health and Environment issued new COVID-19 safety guidelines regarding renewed mask use and social distancing at indoor public places and schools during the upcoming academic year — whether individuals are vaccinated or not.

The prompt for these policies was the rapid spread of the Delta variant, a more transmissible and dangerous version of the disease. The latest data from the CDPHE shows that the variant has now been confirmed in 48 Colorado counties — three-quarters of the state's 64 counties, and all of the most populous.

In "COVID-19 Delta Variant: Places It's Spreading in Colorado," published at the end of June, we reported on the rise of the strain, which is technically known as B.1.617.2. It accounted for 55.74 percent of new COVID-19 cases in Colorado for the week ending June 6, with the figure jumping to 75 percent for the week ending June 13.

As of June 23, Delta variant cases had been confirmed in 23 counties, with Mesa County leading the pack. By our July 2 update on the Delta variant, 36 counties had confirmed Delta variant cases, though only two had 100 or more cases: Mesa and El Paso.

In the four weeks between July 2 and July 30, the most recent date for which CDPHE statistics are available, the Delta variant spread farther — and faster. Over 95 percent of new virus infections in this state are now tied to the Delta variant. The latest survey shows thirteen counties with fifty or more cases and seven with at least 100: Pueblo County went from no Delta variant cases on June 23 to fifty, while Larimer County jumped from 2 to 58, Adams County from 10 to 86, and Jefferson County from 2 to 109. El Paso went from 103 on June 23 to 543 on July 30; Mesa rocketed from 218 on June 23 to 890 on July 30.

Sixteen Colorado counties have no confirmed Delta variant cases: Baca, Cheyenne, Costilla, Crowley, Dolores, Hinsdale, Huerfano, Jackson, Kiowa, Lake, Logan, Mineral, Phillips, Prowers, San Juan and Yuma. But that doesn't mean the strain isn't spreading there: The CDPHE didn't have complete stats related to breakthrough cases and hospitalizations among vaccinated residents in any of these sixteen counties for the two months between April 1 and June 1, most likely because of a shortage of resources in the rural areas.

The state health department hopes to improve that situation. In a July 31 release, the CDPHE stressed that it has amended its public-health orders related to laboratory data reporting and vaccine access and data reporting for COVID-19 "to better track variants and double down on removing any barriers to accessing the vaccine."

Here are the thirteen Colorado counties with at least fifty confirmed Delta variant cases as of July 30, listed from least to most, and including case counts from both June 23 and July 2:

Pueblo
0 Delta variant cases on June 23
10 Delta variant cases on July 2
50 Delta variant cases on July 30

Larimer
2 Delta variant cases on June 23
9 Delta variant cases on July 2
58 Delta variant cases on July 30

Denver
6 Delta variant cases on June 23
10 Delta variant cases on July 2
66 Delta variant cases on July 30

Weld
6 Delta variant cases on June 23
13 Delta variant cases on July 2
74 Delta variant cases on July 30

Adams
10 Delta variant cases on June 23
19 Delta variant cases on July 2
86 Delta variant cases on July 30

Douglas
20 Delta variant cases on June 23
28 Delta variant cases on July 2
87 Delta variant cases on July 30

Boulder
12 Delta variant cases on June 23
16 Delta variant cases on July 2
105 Delta variant cases on July 30

Moffat
18 Delta variant cases on June 23
40 Delta variant cases on July 2
107 Delta variant cases on July 30

Garfield
27 Delta variant cases on June 23
44 Delta variant cases on July 2
108 Delta variant cases on July 30

Jefferson
2 Delta variant cases on June 23
17 Delta variant cases on July 2
109 Delta variant cases on July 30

Arapahoe
12 Delta variant cases on June 23
30 Delta variant cases on July 2
165 Delta variant cases on July 30

El Paso
103 Delta variant cases on June 23
237 Delta variant cases on July 2
543 Delta variant cases on July 30

Mesa
218 Delta variant cases on June 23
418 Delta variant cases on July 2
890 Delta variant cases on July 30

Click to read the CDPHE's updated "Practical Guide for Operationalizing CDC’s School Guidance" and Colorado's fifth amended public-health order related to COVID-19, which will expire on September 1 unless it's "extended, rescinded, superseded or amended in writing."