President Biden is said to be giving "strong consideration" to new requirements for federal employees to help arrest the spread of the delta variant of the coronavirus.

One option under consideration: verifying that federal employees are vaccinated for COVID-19 using an "attestation of vaccination," a source familiar with the deliberations tells NPR's Tamara Keith.

Under the policy, federal employees who are not confirmed as vaccinated would be required to wear masks at all times while at work and be tested regularly for the virus, the source said, speaking on the condition of anonymity.

Completion of the review of the policy is expected later this week.

Biden was asked himself by reporters Tuesday whether he's considering a vaccine mandate for the federal workforce. "It's under consideration right now," he replied.

In a statement, Biden said he would lay out his next steps on how to get more Americans vaccinated on Thursday, noting that vaccinations are the best way to protect against the delta variant.

"More vaccinations and mask wearing in the areas most impacted by the Delta variant will enable us to avoid the kind of lockdowns, shutdowns, school closures, and disruptions we faced in 2020," he said.

New CDC guidance

The president's statement followed revised guidance from the Centers for Disease Control and Prevention on Tuesday. The CDC reversed a position, recommending that fully vaccinated people should wear masks indoors if they're in places with "substantial" or "high" spread of the virus.

Most United States counties currently fall under those two categories.

Added Biden in his statement: "I hope all Americans who live in the areas covered by the CDC guidance will follow it; I certainly will when I travel to these areas."

The delta variant is at least two times as contagious as the strain that first circulated in the U.S. and is the driving force behind a new surge in cases nationwide.

"This was not a decision that was taken lightly," CDC Director Dr. Rochelle Walensky said Tuesday, of the updated guidance.

But Walensky said the agency had to take into account the surge in cases, and data that shows that while rare, vaccinated people can still contract and spread the virus.

"The delta variant is showing every day its willingness to outsmart us," she said.

Vaccine mandates are on the rise

On Monday, the federal Department of Veterans Affairs announced it will require all front-line health care workers to get vaccinated in the next two months.

In New York City, Mayor Bill de Blasio announced all city workers would have to either get vaccinated or tested weekly for the virus. In California, Gov. Gavin Newsom declared a similar policy for state employees and health care workers.

The CDC is also now recommending universal indoor masking for all teachers, staff, students and visitors to K-12 schools, regardless of vaccination status.

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