WISCONSIN — Both the Centers for Disease Control and Prevention and the Wisconsin Department of Health Services recently issued new guidelines on mask usage.

Citing the delta variant, fully vaccinated people are encouraged to wear masks in some instances.

The CDC and DHS recommend that people who are vaccinated should wear masks indoors in parts of the U.S. where COVID-19 is surging, notably in areas classified as having "substantial" and "high" transmission of the coronavirus, as noted by county level on the CDC website.

Transmission rates are determined by the CDC using the following data:

In Wisconsin, a significant number of counties are classified as "high" and another handful of counties are considered to be "substantial" transmission areas. As of Aug. 30, there are 67 of 72 counties with "high" levels of transmission. This equates to approximately 93% of the state.

Below is a map denoting each county's most recent classification. 

"This weighs heavily on me. I know at 18 months through this pandemic, not only are people tired, they're frustrated," CDC Director Walensky said when announcing the change. "This was not a decision that was taken lightly."

The CDC and DHS are also encouraging all teachers, staff, students, and visitors of K-12 schools should wear masks indoors regardless of vaccination status. The health department noted at the time that while breakthrough cases are possible, 98% of all Wisconsin COVID-19 cases were found in unvaccinated people.

Unvaccinated people are still advised to wear a mask in all settings and maintain social distance.