Colorado gubernatorial candidate Heidi Ganahl has tested positive for the coronavirus and will be sidelined from campaign events this week, a campaign spokeswoman told Colorado Politics Monday morning.

The University of Colorado regent and the leading Republican challenger to Democratic Gov. Jared Polis, is vaccinated and experiencing mild symptoms, Lexi Swearingen said.

Ganahl won’t be attending the candidate forum scheduled Thursday in Fort Lupton, which would have been the first time all the major GOP candidates for governor were to have appeared on stage together. The forum is sponsored by the Republican Women of Weld.

Ganahl and members of her family learned they had the virus over the weekend, her campaign said.

The diagnosis comes as the omicron variant sweeps through the country, hitting Colorado particularly hard, according to data released by the Colorado Department of Public Health and Environment.

On Friday, the state reported 9,287 new cases, reflecting a sharp upswing in cases over the previous week, according to data compiled by the New York Times.

Thursday’s sold-out Republican gubernatorial forum will proceed with seven of the 14 declared GOP candidates in attendance, a spokeswoman for the sponsoring group told Colorado Politics on Monday. Candidates who have confirmed they will attend include Greg Lopez, Danielle Neuschwanger, Jack Dillender, Darryl Gibbs, Jeff Fry, Jason Lopez and Jon Gray-Ginsberg.

Polis and his partner, Marlon Reis, tested positive for the virus in late November 2020, before vaccines had become available.

Denver Mayor Michael Hancock announced on Saturday that he had tested positive for the coronavirus and was quarantining with mild symptoms.

Last week, Denver extended its indoor mask order through Feb. 3, and metro area counties Boulder, Broomfield, Adams, Jefferson and Arapahoe are continuing with their mask requirements, which vary somewhat in the specifics.

In mid-December, U.S. Rep. Jason Crow became the fourth member of Colorado’s congressional delegation to report testing positive for COVID-19, following an official trip to Ukraine. Fully vaccinated, he said he was experiencing mild symptoms and has since emerged from isolation, a spokeswoman told Colorado Politics.

U.S. Sen. John Hickenlooper, who was also fully vaccinated, tested positive in August, and U.S. Reps. Ed Perlmutter and Doug Lamborn both came down with the virus in late 2020. All experienced mild symptoms.

Colorado’s toll from COVID-19 stands at 10,485 as the global pandemic approaches the beginning of its third year and the highly contagious new variant surges.  Public health officials say the vast majority of hospitalizations and deaths due to the virus are among the unvaccinated.

This developing story has been updated.