Unvaccinated people in medical facilities, homeless shelters, jails and prisons must continue to wear masks inside, health officials said Saturday as they extended Colorado’s only statewide mask mandate.

“The prevalence of the Delta variant, coupled with the fact that many eligible Coloradans are not fully vaccinated, is threatening our progress here in Colorado,” Scott Bookman, COVID-19 incident commander at the Colorado Department of Public Health and Environment, said in a news release.

The mask mandate, which had been expected to expire in June, will now expire Sept. 1, unless it is extended for a third time. The rule exempts children under the age of 11, people with medical conditions who cannot tolerate wearing masks and “individuals who are actively engaged in a public safety role,” like firefighters, police officers and paramedics, among others.

The Centers for Disease Control last week recommended that even vaccinated people wear masks in indoor public places in counties with “high” or “substantial” spread of COVID-19 — which includes the majority of counties in Colorado. But local and state authorities have so far declined to require masks in Denver or Colorado as a whole.

The state’s health department has recommended school districts consider requiring masks for staff members and students as school resumes this fall.