Facebook will require all US employees wear masks on its office campuses, even if they're fully vaccinated

• Facebook's US employees will have to wear masks in offices from Wednesday onwards.
• The mask policy applied to all employees, including fully vaccinated people, Facebook told Insider.
• Facebook on Thursday told staff that they must be fully vaccinated before they return to the office.

Facebook on Monday announced it would require all US employees to wear masks on the company's office campuses, even if they're fully vaccinated against COVID-19, CNBC first reported.

The new policy will start on Wednesday and remain until further notice. "The health and safety of our employees and neighbors in the community remains our top priority," a spokesperson for the company told Insider in a statement.

"Given the rising numbers of COVID cases, the newest data on COVID variants, and an increasing number of local requirements, we are reinstating our mask requirement in all of Facebook's U.S. offices, regardless of an employee's vaccination status," the spokesperson said.

The mask policy comes the week after the social-media giant announced that staff coming into US offices must be fully vaccinated.

Read more: Media companies including Bloomberg, The Washington Post, and ViacomCBS detail their return-to-office plans as workers push for flexibility after the pandemic

It was prompted by The Centers for Disease Control and Prevention's (CDC) updated guidelines, which recommended vaccinated people wear masks indoors because they still transmit the virus. It comes as COVID-19 cases are spiking in the US, fueled by the more infectious Delta variant.

Alphabet, Google's parent company, followed suit, has also said all employees should wear masks in its office, regardless of their vaccination status, as they return to work.

Insider asked Facebook for comment, but did not immediately receive a response.