These islands are welcoming travelers with 10-day-old COVID tests — but is that really effective?

Both Jamaica and the Bahamas have reopened to international visitors, though the latter will now ban travelers from the U.S. As with many destinations, the Caribbean countries established a negative COVID-19 test requirement for incoming travelers.

While a negative test result returned within 72 hours is common (and some destinations are even demanding testing upon arrival), Jamaica and the Bahamas are asking for coronavirus tests taken within 10 days.

Sure, destinations requiring a test taken within three days have made it extremely difficult for many travelers to visit: Getting a rapid test taken and having the results returned prior to departure is next to impossible for people all over the country. But a 10-day-old test seems almost irrelevant, considering how quickly cases are surging around the country.

Of course, a negative COVID-19 test isn't the only barrier to entry for travelers heading to these island nations. But is a test taken almost two weeks ago really a sufficient indicator that a traveler is healthy?

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"Given that the quality of COVID-19 testing is still uncertain and so many things could happen in the time between when the test performed and when the person arrives ... an old test can’t guarantee that a traveler is negative for COVID-19," said Dr. Hanh Le, senior director of medical affairs at Healthline (owned by TPG’s parent company, Red Ventures).

There are other steps travelers must take before flying to either the Bahamas or Jamaica, though neither has a mandatory quarantine period.

Travelers bound for the Bahamas must complete an electronic Health Visa, which can take up to 72 hours to process. The form asks for contact information, travel history from the past six weeks and health information — including uploaded documentation of a negative RT PCR COVID-19 test. They will not accept rapid antigen or antibody (IgG/IgM) test types, among others.

The test must be taken no more than 10 days prior to the date of travel.

[pullquote source="Dr. Elaine Hanh Le, Healthline Media Chief Medical Officer"]"...a 10-day window is large enough that it increases the likelihood of missing many travelers who may be asymptomatic carriers."[/pullquote]

But Le says that "10 days is a fairly large window, during which time a person may become exposed to COVID-19 and still not exhibit symptoms."

Also, children under 10 are not required to present a negative COVID-19 test, despite the fact that children can still contract and spread the virus. Just last week, a top health official in Victoria, Australia, said that child-to-child transmission is "more apparent" than originally understood.

Jamaica's entry requirements are even more relaxed. Visitors must complete a Travel Authorization form before boarding the flight, but only travelers 12 and older from Arizona, Florida, New York and Texas must upload negative COVID-19 PCR test results.

"These results, provided by a CAP-accredited lab, are required for travelers from high-risk locations to receive the Travel Authorization certification, and must also be presented upon arrival in Jamaica," said Jamaica's tourism authority.

But even a more recent test — say, one taken within 72 hours — doesn't really guarantee travelers haven't been exposed.

"Travel is a time when folks can face a lot of exposures," Kumi Smith, Ph.D., assistant professor of epidemiology and community health at the University of Minnesota in Minneapolis, told TPG. "Someone who is known to be negative upon departure could potentially acquire infection in transit and still play a role importing transmission into their destination country."

Related: When will international travel return? A country-by-country guide to coronavirus recovery.

Regardless of the efficacy, it can still be incredibly difficult to get a coronavirus test in the U.S. — to say nothing of how long you'll have to wait for the results. Due to the backlog, cities such as San Antonio and Austin, for example, are still only testing people displaying symptoms. So, even if you could travel to the Bahamas right now, you might not get a test in time for your island escape.

"It is frustrating that, several months into this worldwide pandemic, people still do not have a greater sense of confidence in our ability to access reliable testing," Le said. "There are a number of complicated factors at play, key of which is the lack of coordination between the teams and companies performing the research into SARS-CoV-2."