DENVER — Denver and two other Colorado counties raised their COVID-19 community level risk to "medium" Friday, underscoring the need to remain vigilant as the BA.2 sublineage of the omicron variant continues to drive up cases across the state.

Denver Department of Public Health and Environment (DDPHE) officials said in a news release Friday residents should consider taking more precautions as the number of COVID-19 cases per 100,000 people have now exceeded 200, shifting the COVID-19 community level from low to medium, per the latest guidelines from the U.S. Centers for Disease Control and Prevention (CDC).

The new guidelines — based on lagging indicators such as the number hospital beds being used and the number hospital admissions, instead of leading indicators (such as the total number of new COVID-19 cases in an area) — recommend that people living in a county with "medium" COVID-19 community risk talk to their doctor about whether they need to wear a mask and take other precautions. They also suggest people stay up-to-date with their COVID-19 vaccinations and get tested if you experience cold-like symptoms.

"Since early April, rates of COVID-19 cases have been slowly, but steadily, increasing," DDPHE officials said Friday. "While the current surge is not expected to be nearly as large as the Omicron surge earlier this year, it's a good opportunity to remind our community how to stay safe, protected and prepared for COVID-19."

Denver's one-week incidence rate of cases per 100,000 people as of Friday was 209, according to city data. The county's 7-day average positivity rate stood at 7.95%, nearly 3 percentage points above what is recommended by officials to curb transmission of the virus.

Earlier Friday, Boulder Conty Public Health officials said in a news release the shift in their county's COVID-19 community level to "medium" indicates the risk of getting infected with the novel virus is increasing in the community, and additional measures to curb transmission are recommended to keep other safe and limit the strain on healthcare systems in Boulder County.

"The increase of cases was not unexpected as the more contagious BA.2 variant spreads locally and nationally," said Carol Helwig, communicable disease program manager for Boulder County Public Health (BCPH). "It is important for all of us to stay mindful of applying measures to protect each other, especially to protect people who are older or who have underlying medical conditions. Therapeutics can prevent the most severe outcomes of disease. It's a good time to talk to your medical provider and ensure that you have a plan to access treatment promptly if you become ill."

Among the recommendations to keep yourself and others safe as cases continue to increase:

Mineral County in southwestern Colorado is the third county under COVID-19 Level Medium, per the CDC's COVID-19 county map. The previous CDC guidelines, which focused solely on the level of community transmission, shows a large chunk of the state is under a level of risk where the use of a face mask is recommended.

On Thursday, San Juan Basin Public Health, which serves La Plata and Archuleta counties, warned its constituents to consider taking additional precautions to curb transmission of the coronavirus as concentrations of the virus in Durango’s wastewater have more than doubled in the past 16 days, to levels last seen in early February, according to a news released obtained by our partners at The Denver Post.

Data from the state shows the BA.2 sublineage of the omicron variant accounts for nearly three quarters of all infections in Colorado, while its cousin, BA.2.12.1 — which is believed to be 25% more transmissible than BA.2 — makes up nearly 20% of all infections.

BA.2.12.1 is set to become the dominant variant in the U.S. by the end of this week.