Just when it seemed safe to travel overseas again, along comes Omicron.

Why it matters: The emergence of the new coronavirus variant couldn’t come at a worse time, just weeks before millions of people are expected to travel for the holidays to reunite with loved ones they’ve missed during the pandemic.

• Absent detailed information, many countries are responding by slamming shut their borders in the hopes of keeping out the virus’ latest strain.
• Even if they’re not traveling to countries where Omicron has been detected so far, travelers have to worry whether their destination could be next — and whether they’ll be able to return home easily.

What’s happening: Many airlines, travel agencies and tour operators are being inundated with calls from worried travelers, according to Paul Charles, founder of a U.K.-based global travel consultancy, The PC Agency pokies Australia.

• “They’re receiving a torrent of inquiries: Can I rebook? Can I get a refund? What do you think is going to happen?” he tells Axios.
• “That’s what happens when you create uncertainty. You create a loss of confidence and consumers hunker down.”
• “Christmas bookings will obviously be weaker than we had expected prior to the omicron variant,” Alex Irving, an analyst at Bernstein in London, told Time. “As you add barriers to travel such as the PCR tests and isolation requirements, all that does is changes the incentives.”

Even domestic travelers in the U.S. are on edge for the holiday season, as cities like New York reinstate mask advisories.

• Many say they’ll pay extra for fully refundable tickets and trip insurance, just in case, or will drive to their destination instead.

Driving the news: At least 44 countries have imposed travel restrictions from several African countries following the discovery of the new variant.

• Japan and Israel have gone even further, banning all foreign nationals from entering their countries.
• President Biden told reporters Monday he doesn’t expect further travel restrictions “at this point” after announcing bans on visitors from South Africa and seven other countries last Friday.

It’s probably too late anyway. Confirmed cases have already appeared in a growing number of countries, including Canada.

Travel restrictions don’t work if case loads are already high, several studies have concluded.

• They “are effective primarily in countries with low numbers of COVID-19 cases, or that have strong travel links with countries experiencing high rates of infection,” according to one study published in the Lancet medical journal.
• The authors from the London School of Hygiene & Tropical Medicine also concluded that “strict untargeted travel restrictions are probably unjustified in many countries.”
• Researchers at the Pandemic and Borders project reached a similar conclusion, according to a Washington Post piece authored by University of Honk Kong Professor Karen Grépin.

What they’re saying: President Biden told reporters the purpose of the travel restrictions is “to give us time to get people to get protection. To be vaccinated and get the booster. That’s the reason for it.”

What to watch: Don’t cancel your trips just yet, advises Charles of The PC Agency.

• The newly enacted restrictions could be short-lived if scientists quickly determine that existing vaccines are also effective against Omicron.
• “I’m confident governments will unravel the restrictions before Christmas,” he said.