The US will open its borders to vaccinated foreign travelers on Nov. 8, a White House official said, a move that will expand travel options for those who’ve gotten their shots and clamp down on those who haven’t.

The measures are the biggest changes to US travel policy since the early days of the Covid-19 pandemic, and replace a system that flatly barred most foreign nationals coming directly from certain places, including Europe, India, Brazil and China.

Instead, under the new system, vaccinated people who have had a negative test in the prior 72 hours will be able to board a flight to the US as long as they share contact tracing information. Unvaccinated foreigners will be generally barred from entry, while unvaccinated Americans will need a negative Covid-19 test.

The move was first announced Sept. 20, but the Biden administration didn’t immediately say when the measures would kick in. Airlines, battered by the coronavirus crisis, have applauded the move. Transatlantic flights between the US and Europe — filled with premium travelers — had been the single most profitable part of the global aviation market. 

The Nov. 8 date applies to a change in air travel rules, as well as an opening along land borders with Canada and Mexico announced earlier this week.

The US will consider people arriving by plane vaccinated if they received shots that are either authorized by the Food and Drug Administration or have an Emergency Use Listing from the World Health Organization. The same will likely apply to those arriving by land, the official said.

The decision to accept WHO-cleared shots not used in the US means millions of travelers who have received doses developed by AstraZeneca Plc, as well as China’s Sinopharm Group and Sinovac Biotech Ltd., will be allowed to enter.

It’s not yet clear how the US will treat people who have mixed shots — one dose of one vaccine followed by a dose of another.