According to instructions released by the White House Office of Management and Budget (OMB) on Wednesday, July 28, several U.S. federal agencies imposed masks at federal buildings in COVID-19 hot spots.

The action came after the Centers for Disease Control and Prevention (CDC) released guidance on Tuesday urging vaccinated people to wear masks indoors in regions where COVID-19 community transmission is substantial or high.

Masks are required indoors in government facilities for all employees and visitors, whether or not they have been vaccinated, according to the White House, Reuters reported.

On Tuesday, the transmission rate had increased to 63.4 percent. COVID-19 community transmission rates are high in 49.9% of U.S. counties, and substantial in 16.7%, according to the CDC. On the same day, CDC revised its stance on mask guidance for vaccinated Americans.

As of Wednesday, nearly 67 percent of U.S. counties had substantial or high transmission rates, up from 63.4% on Tuesday.

Significant transmission is defined as more than 50 new cases per 100,000 people in the previous week, while high transmission is defined as more than 100 cases per 100,000 people in the last week.

The CDC also suggested that all students, teachers, and staff in kindergarten through 12th grade wear masks, regardless of whether they had been vaccinated, in a toughening of guidelines provided earlier this month.

The highly contagious Delta variant of the coronavirus has been on the rise in the United States after being first detected in India. It has quickly spread to account for more than 80% of US coronavirus infections.

On Thursday, President Joe Biden is expected to announce stricter mandates for federal agencies.

Jason Miller, OMB’s deputy director for management, stated in an email issued late Tuesday to all federal departments, “in areas of substantial or high community transmission, agencies must require all federal employees, onsite contractors, and visitors, regardless of vaccination status, to wear a mask inside of federal buildings. As of today, that includes the Washington, D.C., area.”

It added that people “not fully vaccinated also need to continue to physically distance consistent with CDC guidance.”

Indoor masking is now required at all Defense Department properties in areas with significant or high transmission rates, the Pentagon said.

The Energy and Interior Departments also confirmed that the policy had been enacted.

On Monday, Biden’s administration mandated that all Veterans Affairs staff get the jab, and on Wednesday, the Department of Homeland Security announced that all of its 240,000 employees, regardless of vaccination status, will be required to wear a mask indoors and practice safe distancing.

According to the White House and the United States House of Representatives, vaccinated people must wear masks indoors in federal facilities.