What Happens If You Test Positive While Traveling?

Millions of Americans are expected to travel over Christmas and New Year’s, with some booking sites, such as Hopper, predicting that even international travel will approach prepandemic levels. As travelers try to decide whether to commit to their plans, many are grappling with the question: What if I test positive even though I’m vaccinated, and get stuck somewhere far from home?

It’s not an outrageous question. In 2019, more than 5 million people flew into the United States over the holiday period, according to Customs and Border Protection data. Every person age 2 and up who is returning to the United States from abroad by air — including vaccinated American citizens — has to take a coronavirus test within a day of their flight home. Even if the numbers of those traveling hover far below 2019 levels, some people will have to cancel their flights to the United States because they tested positive.

Of course, for people who become severely sick with Covid, the immediate concerns go far beyond getting stuck. Over the past week, an average of 7,052 people around the world — including nearly 1,300 people in the United States — died each day from the coronavirus. For vaccinated people, the implications are generally less dire. Worrying about your inability to board a flight can feel self-indulgent when I.C.U.s in many places are overwhelmed. But from a planning perspective, the consequences are not insignificant.

What are the odds of testing positive if you’re vaccinated?

Alas, this was difficult to answer even before the Omicron variant popped up in November. While research once put the odds of the average vaccinated American contracting Covid at around one in 5,000 per day, that figure is likely to increase as Omicron spreads.

Though much is still unknown about the variant, early indications suggest that it infects vaccinated people at higher rates than previous variants. One small study found that the majority of the 43 people first identified with Omicron in the United States were fully vaccinated when they tested positive. There have been some early indications that the variant might cause milder disease than other variants and scientists expect that it’s less likely to become severe in vaccinated people.

Boosters should decrease a vaccinated person’s odds of becoming infected with multiple variants. Early data suggests that booster shots for the Moderna and the Pfizer-BioNTech vaccines offer substantial protection against Omicron, Dr. Anthony S. Fauci, President Biden’s top medical adviser, said Wednesday. Booster shots start having an effect in many people in just a few days, meaning that it’s not too late to reap the benefits even if you’re traveling soon, said Dr. Aaron Milstone, a professor of pediatric infectious disease at Johns Hopkins University School of Medicine,who is studying the immune response to booster doses. Even stronger protection is likely to kick in 10 to 14 days after the shot, he and other experts noted, so the sooner you get one, the better.

If I test positive while traveling within the United States, will I have to stay put?

When driving across a state border, no one is going to ask you to flash negative test results. Neither states, airlines, airports or most other forms of transportation require negative coronavirus tests from domestic travelers with a few exceptions: Hawaii and the U.S. Virgin Islands.

If you do end up testing positive — perhaps because a private gathering requires a test — the responsible course of action would be to isolate yourself from others because you are contagious, said Dr. Emily E. Volk, the president of the College of American Pathologists, an organization of physicians who perform biopsies and diagnose disease.

“It’s the morally and ethically correct thing to do,” she said.

But in most of America it’s up to the individual to decide how to proceed. The Centers for Disease Control and Prevention advises isolating for at least 10 days after testing positive, even if a person never develops symptoms. In a recent article for The Atlantic magazine, the writer Katharine J. Wu argues that this recommendation is outdated and that vaccinated people should be able to test out of isolation sooner. Dr. David Freedman,the president-elect of the American Society of Tropical Medicine and Hygiene, made a similar point in a recent interview: Once you’ve tested negative, you should feel OK about traveling again, he said.

Either way, for better or worse, these are just recommendations. Some employers, educational institutions, states and counties have additional isolation policies, but few locations actively enforce quarantine. Depending on where you tested positive, you might get a call from a contact tracer. Or you might not.

So what happens if you test positive while traveling internationally?

A crucial step while planning any trip is to familiarize yourself with the points at which you will have to take a test and what would happen if you or someone you were traveling with tested positive, including the length and type of quarantine. In some destinations, the only concrete consequence of a positive test is that you can’t board a flight. In other destinations, health officials might require you to stay in a government hospital for more than 10 days.

Pack as if you’re going to get stuck, advised Amy Eckhardt, the owner of World View Adventures, a travel agency based in Buffalo, N.Y. That might mean bringing two additional weeks of medication and your work laptop.

Ms. Eckhardt has yet to have a client test positive while abroad, but she’s learned from her own experience. To celebrate her 40th birthday, she spent about a month and a half in Mexico last winter before she had the opportunity to get vaccinated. For the final leg of her trip, she picked a resort in Costa Mujeres that offered free on-site testing and covered the costs of food and lodging during quarantine, if required.

When her results came back positive on Jan. 31, she said, hotel employees asked her to put on a “biohazard orange” wristband and to move from her oceanfront room to a basement room in “the quarantine section.” Because she was the hotel’s first guest to test positive, the staff was still figuring out how to handle such situations. Her resort stationed a guard outside her door, and initially she had to move to a new room across the hall every three days, while people in hazmat-like suits and goggles sanitized the room and placed new towels in the bathroom.

Fortunately, she never developed any serious symptoms and her primary obstacle was boredom, which she countered by posting detailed updates about the iguana on her patio and other humorous observations in a private Facebook group for travel agents. After completing her 10 days of quarantine, she tested negative and flew back to the United States.

How long does it take to test negative?

Someone infected with Covid will typically test positive for five to eight days, said Dr. Freedman of the American Society of Tropical Medicine and Hygiene.

In rare cases someone might test positive for as long as six weeks, even though the individual is no longer contagious, he said. There is a way to get around this in some cases. Many countries and airlines will accept a certificate of recovery from a doctor or health official in lieu of a test.Erika Richter, a spokeswoman for the American Society of Travel Advisors, a trade organization, urged people to review the C.D.C.’s highly specific requirements for that certificate.

Dr. Volk, the president of the College of American Pathologists, recommends that anyone who tests positive with an at-home or antigen test, follows up with a P.C.R. test, which is much more likely to give you a true positive.

Will travel insurance cover costs if I test positive?

It depends on the type of insurance. Some policies will cover additional airfare and lodging for up to seven days past your originally scheduled return date, effectively covering just a week of quarantine, my colleague Elaine Glusac explains in this article on travel insurance. Some policies will also cover medical costs abroad, which are often excluded from traditional health insurance policies.

How do I avoid testing positive while traveling?

Taking the sorts of precautions you embraced before you were vaccinated — avoiding crowded indoor events and wearing a mask — would be wise.

“Vaccines are doing an amazing job of keeping people alive, but masks will keep people from getting infected,” said Dr. Milstone of Johns Hopkins University School of Medicine.

It’s also worth remembering that you need to start being extra cautious before you travel — if you’re infected shortly before you depart you might not test positive until you’re on your trip.

Jenny Mikkelson, the vice president of Travel Beyond, a luxury safari company, has seen this happen. The day after Thanksgiving, 10 Americans flew to Cape Town from Minneapolis. All of them had tested negative in the United States. In order to fly to Botswana for their safari, they had to take another test. One traveler tested positive. A couple of days later a second American traveler who had stayed behind with that traveler also tested positive. Given the timing, it seemed likely that the first traveler had been infected back in Minneapolis, Ms. Mikkelson said. Neither developed symptoms during their quarantine in a luxury hotel, but they missed the safari. Once they both tested negative, they flew home.

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