DENVER (KDVR) — According to the U.S. Centers for Disease Control and Prevention, two-thirds of Colorado’s counties should be under indoor mask mandates, including some counties in the Denver metro area.

The CDC today revised its earlier guidance on whether vaccinated persons should wear masks. In a press conference, the federal health authority introduced a new set of recommendations on masks.

The new guidance recommends all vaccinated and unvaccinated persons wear masks indoors in areas of high or substantial degrees of community infection.

According to state health department data, most of Colorado’s counties have COVID rates that qualify for either high or substantial rates of community infection.

This includes some of the Denver metro region.

The CDC categorizes “high” community transmission as any location with a 7-day cumulative incidence rate of more than 100 cases per 100,000 as well as a test positivity percentage of 10%.

“Substantial” areas of community transmission applies to areas with between 50 and 99.99 cases per 100,000 and test positivity percentage of 8-9.99%.

Gov. Jared Polis did not say if he would issue a mask mandate based on the CDC’s recommendation, instead using the opportunity to push for more vaccinations.

“We had mask mandates before we had an effective vaccine,” said Polis. “So now that we have a vaccine that’s far more effective than a mask that’s the best step that anybody can take to protect themselves and their family.”

How are county health departments responding?

So far, none of the health departments from any of these counties have said they plan to implement the CDC’s new mask guidance.

“At this point there are no public health orders in effect in Jefferson County that require masking any setting,” said Dr. Dawn Comstock, executive director for the Jefferson County Board of Health. “This is a very strong recommendation only, and at this point it does not look like the state will be requiring masking in schools.”

“If our county wide incidence rates continue to rise rapidly, then I will be forced to put another public health order in place,” Comstock said. “If an as-yet identified variant comes along which makes children become much more ill, effects them more seriously when they are infected, then I will be forced to put in a public health order.”

Denver health officials gave a similar response.

“While cases in Denver and the Front Range are increasing, Denver’s vaccination rate is high and hospitalization rate is low,” read a statement. “At this time, we are not recommending indoor masking for those who are vaccinated.”

Tri-County Health Department said officials are working with state health department and their school districts to find the most appropriate solutions for the communities they cover.

“We will see what their guidance is,” Douglas County commissioner Lora Thomas said. 

Thomas says Douglas County is keeping an eye on their individual county metrics while also waiting for updates from TCHD.

“We do have the ability to opt out of any public health order that Tri-County makes that we believe is not beneficial for our citizens,” Thomas said. 

Boulder County Public Health has taken a stronger stance on masking indoors, but has so far not made any formal health order.

“BCPH is aware of the expected CDC mask guidance changes reported in the news this morning, and we are awaiting official publication of updated mask guidance from CDC and subsequently CDPHE. When that official guidance is available, we will review our current guidelines. However, as you know BCPH has consistently recommended mask-wearing indoors as a safe, easy, effective and evidence-based COVID-19 prevention strategy. Given that the more transmissible, Delta variant is widely circulating in our state, we support and strongly recommend mask-wearing as a precaution for anyone in indoor public spaces regardless of vaccination status,” a spokesperson for the department said in response to a request from FOX31 News.

Which counties are driving COVID rates?

Much of the public conversation this summer has revolved around counties with disproportionately high case rates, typically these are counties with lower-than-average vaccination rates such as Moffat, Mesa or Weld counties.

Overall, Colorado has added 17,000 COVID cases since June 21, when the average case rate bottomed out. Since then, statewide cases have risen back up to around the rates they were in the last week of May.

The state’s western counties may have higher case rates, but it is the most populous counties driving the surge.

Only ten counties account for 75% of Colorado’s COVID cases since June 21 – El Paso, Arapahoe, Denver, Adams, Mesa, Jefferson, Larimer, Weld, Douglas and Boulder.

Together, these Front Range counties have added 13,515 cases since June 21.

El Paso alone has produced 2,851 cases since summer officially began. Arapahoe and Denver have produced the second- and third-most with 1,592 and 1,520, respectively.

This reflects the larger national picture, where the U.S.’s upward swing in recent case rates comes largely from a handful of states.