‘I booked a flight to Europe, now what?’ How the EU’s border ruling affects you

The European Union voted on Monday to tighten its border controls for U.S. residents for nonessential travel amid the ongoing spread of the Delta variant in the United States.

It’s important to note that this does not affect critical business trips, and has no bearing on U.S. flights bound for the United Kingdom, which left the EU in 2020 and at the start of this year was no longer obligated to apply the bloc’s rules as part of its exit.

Instead, the ruling applies to the EU’s 27 countries. The plan, as of now, is to kick the United States and Israel off the bloc’s “safe” list. The safe list is relatively permissive. It means tourists or nonessential travelers can enter the EU without proof of vaccination.

The EU’s new ruling potentially changes that, a decision that’s hitting shares for European airlines hard on Tuesday.

Here’s what the new rules mean:

Can I still travel on holiday to Europe?

While designed to avoid confusing travelers with a patchwork of rules and regulations that differ from one country to the next, the list is only a recommendation, and therefore, is not binding. Member states are still free to determine their own policy, even though the potential for contagion is greater given most EU states have done away with controlling internal EU borders as part of Schengen.

This means every traveler should check with the respective embassy or consulate to familiarize themselves with any potential changes following the decision, as some countries are bound to update their entry requirements. It’s possible that one EU state may be satisfied with proof of a negative PCR test that is no older than 48 hours, while another may require a period of self-quarantine upon arrival.

What if I am vaccinated?

That’s the safest bet, but here, too, each country ultimately has the authority to deviate from the accepted recommendation. Be aware though that an individual is only considered fully vaccinated once a period of 14 days has elapsed from the time of the second and final inoculation—assuming they did not receive the one-dose Johnson & Johnson shot.

What if my European trip is scheduled for later in the year?

If you want to visit friends and family in Europe, or visit one of the region’s famous Christmas markets, do not despair. It may yet be possible. The “white list” of safe third countries is reviewed and, if needed, updated every two weeks by EU member states. A good indicator as to whether the U.S. might be reinstated on the list is to watch the 14-day incidence rate (the number of new cases per 100,000 people over a two-week period) published weekly by the European Center for Disease Prevention and Control

More must-read business news and analysis from Fortune:

Subscribe to Fortune Daily to get essential business stories straight to your inbox each morning.