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KANSAS CITY, Mo. — Mayor Quinton Lucas says he will bring an indoor mask mandate back to Kansas City after new guidance from the Centers for Disease Control and Prevention.

Lucas did not details on when the indoor mask mandate will begin, but simply said he will be provide more information Wednesday morning.

“I have stuck with CDC guidance throughout the pandemic and today is no different,” Lucas said in a tweet Tuesday night.

Lucas cited national and regional health guidance and discussions with other Kansas City leaders as the basis for the decision.

The CDC said Tuesday that fully vaccinated Americans who live in areas with “substantial and high” transmission should wear masks in indoor public spaces in the wake of rising COVID-19 cases.

CDC Director Rochelle Walensky said they had reviewed new data in recent days that showed fully vaccinated individuals could spread the delta variant more easily than previous versions of COVID-19.

“This new science is worrisome and unfortunately warrants an update to our recommendations,” she said Tuesday.

The CDC’s website has a map that shows counties with substantial and high transmission. That includes a combined 63.11% of counties in the U.S. Every county in the immediate Kansas City metro, including Jackson County, has a high transmission rate, according to the CDC.

“The vast majority of infection is happening with unvaccinated individuals,” Walensky said. She added the concern was vaccinated people may unknowingly introduce the disease to at-risk family or friends.

She said a vaccinated person’s risk of developing symptoms when exposed to the delta variant is reduced 7-fold, and the risk for hospitalization is reduced 20-fold.

The CDC also recommended that all people in schools should also wear masks, regardless of vaccination.