As coronavirus cases surge across the U.S. and present another headwind for return-to-office plans, one major employer is doubling down on its vaccination policy.

Google this week told employees they could lose their job if they don’t comply with vaccination policies, according to documents received by CNBC.

An internal memo said employees must upload documentation proving vaccination status or apply for an exemption by Jan. 18; employees that fail to comply will be put on “paid administrative leave” for 30 days. That would turn into “unpaid personal leave” for up to six months, followed by termination, CNBC reports.

“Our vaccination requirements are one of the most important ways we can keep our workforce safe and keep our services running,” a Google spokesperson told CNBC.

Employees were first told of the vaccine mandate on Dec. 3.

Google has shifted its return-to-office policy several times since the onset of the pandemic; earlier this month, the firm said employees would largely return to the office on a hybrid basis starting in January. A Google spokesperson told The Verge official plans have yet to be set in stone and would ultimately be left up to local offices.

The U.S. is averaging 118,717 new Covid-19 cases each day — up 40% from last month — according to CNN, citing data from Johns Hopkins University.

The omicron variant has also thrown another wrench in return-to-office plans, potentially prompting employers to kick the can down the road yet again.

"It's causing a general groan," Global Workplace Analytics President Kate Lister told Bisnow last month. "The feeling is, 'not again.' Most workers still haven't come back, and companies are trying to get them to come back, but people don't want to, and omicron will add fuel to that fire."