The Biden administration is set to require all foreign nationals entering the U.S. in January to be fully vaccinated.

According to an unnamed White House official who spoke to the Associated Press on Tuesday, the rule will apply to any essential, foreign traveler to the U.S. This includes cross-border visitors like truck drivers all the way up to foreign diplomats visiting or stationed in the country.

The requirement is due to come into effect on Jan. 22.

Citizens and permanent residents of the U.S. will still be allowed to enter the country, regardless of their vaccination status. However, they will still have to take a COVID-19 test beforehand to enter.

This move follows the Biden administration’s lifting of entry restrictions for international visitors on Nov. 4. Nearly 20 months ago, former President Donald Trump initiated the restrictions for entry during the early days of the pandemic. Initially, flights from China were halted in February 2020 before the prohibition was expanded to other countries a month later as infection numbers mounted.

Unlike tourists or other visitors, essential travelers were permitted to enter the U.S. regardless of their vaccination status. The vaccination rule was delayed to allow more time for other countries to vaccinate their nationals and to avoid more disruptions to international trade.

The rule has not yet been announced so details are currently unavailable. According to the AP's source, vaccine requirements will apply to essential foreign workers entering by land or ferry and they will resemble those applied to non-essential foreign travelers.

"While further operational details will be released in the coming weeks, we anticipate that the operational details will be generally consistent with the approach that is already being applied to non-essential travelers," an official told The Hill.