Rochelle Walensky, director of the Centers for Disease Control and Prevention (CDC), pushed for “universal masking” at a Tuesday news conference. Given rising infections from the delta variant, she recommended all students, teachers and staff in K-12 schools wear masks even if they have received the COVID-19 vaccine.

Walensky also told vaccinated people to resume masking indoors in “high” and “substantial” community transmission regions. The CDC classifies every county in Florida and Arkansas as a high-risk area.

Why the return to masking? Walensky said vaccines are not as effective against the delta variant, which accounts for over 80 percent of U.S. cases.

She reported the possibility that vaccinated people could spread the delta variant but confirmed that most transmissions and nearly all hospitalizations occur in the unvaccinated population.

The United States has about 57,000 new COVID-19 cases per day and 24,000 hospitalizations. The country averages fewer than 250 deaths per day.

The new CDC guidance comes as the new school year prepares to get underway. The Alachua County School Board—which heard strong reaction from parents about masks at its last meeting—will decide on Tuesday whether to implement a mask mandate for returning students, teachers and staff.

—With reporting from J.C. Derrick

This story originally appeared in WORLD. © 2021, reprinted with permission. All rights reserved.