Beginning Jan. 15, staffers of the New York–based bank who are not fully vaccinated and have not received a medical, religious, or otherwise legally binding exemption will be put on unpaid leave before ultimately being fired at the end of the month, according to a person familiar with the matter.

The impending firings, which were first reported by Bloomberg, should come as no surprise to Citigroup employees, who first got word of the vaccine mandate more than two months ago. At the time, Citigroup head of human resources Sara Wechter wrote on LinkedIn that the bank’s leadership team had made the decision to require employees to be fully vaccinated “as it has become crystal clear that COVID-19 will not be going away anytime soon.”

“Understanding that there are a range of views about vaccine mandates, this decision was made with careful consideration and analysis,” Wechter wrote in October.

So far, more than 90% of Citigroup employees based in the U.S. are in compliance with the requirement—meaning they have received at least two shots of an approved vaccine—and the number is quickly rising, a spokesperson told Fortune.

With the Omicron variant still pushing case counts in the U.S. higher, companies of all kinds have been ratcheting up their efforts to get employees vaccinated. On Monday, for instance, Starbucks said employees in the U.S. must be vaccinated against COVID-19 by Feb. 9, or they will need to be tested for the virus on a weekly basis. And the Mayo Clinic recently fired about 700 of its workers for not agreeing to comply with its vaccine mandate.

However, those tend to be just a few of the outliers—for now. A November survey by Willis Towers Watson found that, at the time, only 18% of employers surveyed required vaccinations against COVID-19 from their employees. Another 32% said they would do so if and when the federal government’s vaccine mandate for private employers of a certain size takes effect, a requirement whose fate now lies in the hands of the Supreme Court.

On Wall Street, the latest effort to keep employees from getting sick has meant a return to working from home.

For much of the pandemic, investment banking and trading executives have fought to find ways to get their employees back into the office, with the likes of Goldman Sachs CEO David Solomon calling the work-from-home era an “aberration.” But thanks to the virus’s latest mutation, many of the country’s biggest banks—Bank of America, JPMorgan, and Citigroup among them—have asked their staffs to work remotely at the start of 2022.