(AP) — President Joe Biden will require essential, nonresident travelers crossing U.S. land borders, such as truck drivers, government and emergency response officials, to be fully vaccinated beginning on Jan. 22, the administration planned to announce Tuesday.

A senior administration official said the requirement, which the White House previewed in October, brings the rules for essential travelers in line with those that took effect earlier this month for leisure travelers, when the U.S. reopened its borders to fully vaccinated individuals.

Essential travelers entering by ferry will also be required to be fully vaccinated by the same date, the official said. The official spoke to The Associated Press on the condition of anonymity to preview the announcement.

The rules pertain to non-U.S. nationals. American citizens and permanent residents may still enter the U.S. regardless of their vaccination status, but face additional testing hurdles because officials believe they more easily contract and spread COVID-19 and in order to encourage them to get a shot.

The Biden administration pushed the requirement for essential travelers by more than two months from when it went into effect on Nov. 8 for non-essential visitors to prevent disruptions, particularly among truck drivers who are vital to North American trade. While most cross-border traffic was shut down in the earliest days of the pandemic, essential travelers have been able to transit unimpeded.

The later deadline is beyond the point by which the Biden administration hopes to have large businesses require their employees to be vaccinated or tested weekly under an emergency regulation issued by the Occupational Health and Safety Administration. That rule is now delayed by litigation, but the White House has encouraged businesses to implement their own mandates regardless of the federal requirement with the aim of boosting vaccination.

About 47 million adults in the U.S. remain unvaccinated, according to figures from the Centers for Disease Control and Prevention.