Recent media reports suggest fully vaccinated people from the U.S. may soon be able to travel internationally for leisure—but experts say several international focuses, including global Covid-19 surges and local restrictions abroad, may complicate that timeline, the New York Times reports.

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CDC guidance

In its latest guidance easing masking and social distancing requirements for fully vaccinated people, CDC also eased its former recommendation against all non-essential travel. CDC considers people fully vaccinated once two weeks have elapsed since they received either their second dose of Pfizer/BioNTech's or Moderna's Covid-19 vaccine, or the single shot required for Johnson & Johnson vaccine.

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CDC said Covid-19 prevention measures "continue to apply to all travelers," vaccinated or not, including wearing a mask on "all planes, buses, trains, and other forms of public transportation traveling into, within, or out of the United States and in U.S. transportation hubs such as airports and stations."

That said, according to the agency, fully vaccinated people can travel domestically "at low risk to themselves." Specifically, according to CDC, those traveling domestically no longer need to get tested before or after traveling, unless required by local, state, or territorial authorities, nor do they need to self-quarantine following domestic travel.

For international travel, CDC recommends that fully vaccinated travelers continue to "pay close attention to the situation at their … destinations," given the spread of new variants and other factors. However, such individuals no longer need to get tested before departing the United States unless required to do so by their destination location, nor do they need to self-quarantine in the U.S. after returning. They are still required, however, to have a negative test result or documentation of recovery from Covid-19 before they board an international flight to the United States, and they are advised—once back in the United States—to a get a test within three to five days of their arrival.

4 obstacles to 'responsible' travel, according to experts

According to the New York Times, several factors suggest U.S. tourists may soon be able to resume international leisure travel, including the growing vaccination rate in the United States, the increasing number of countries opening their doors once again to U.S. tourists, airlines' resumption of international flights, and the European Union's plan to accept fully vaccinated tourists this summer. 

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But other, more serious factors could obstruct plans for "responsible tourism," the Times reports, including:

1. Covid-19 surges and variants

Even as the U.S. continues to vaccinate residents and ease Covid-19 restrictions domestically, many other countries are experiencing record-breaking surges of Covid-19 cases, hospitalizations, and deaths—surges that could undermine any plans of resuming international travel to certain locations in the near future, the Times reports.

In fact, according to the Times, more new coronavirus cases were reported globally in the past few weeks than at any other people since the pandemic began. And while those figures are largely driven by the ongoing Covid-19 crisis in India, several other nations are seeing "troubling trends," including those popular with U.S. tourists, such as France, Germany, Italy, and Spain.

These trends have direct and indirect implications for U.S. travelers, the Times reports. For instance, the U.S. State Department recently included some of the most popular destinations for U.S. tourists—such as Britain, the Bahamas, Canada, the Dominican Republic, and Mexico—on its "Level 4: Do Not Travel" category due to Covid-19 concerns. And more broadly, the particularly virulent variant in India suggests that emerging variants may threaten travel for some time to come.

2. Unequal, slow vaccine rollouts

According to the Times, vaccination rates remain comparatively low outside the United States. About 32% of the U.S. population is fully vaccinated. But in Italy that number is only 11%, in Mexico it’s 6%, and in Canada it’s just 3%. While the vaccination rate appears to be picking up in some countries, the Times reports, supply chain issues may slow that progress.

This may lead to ethical dilemmas for U.S. tourists, according to the Times. They may be vaccinated, but they’ll be interacting with the citizens of largely unvaccinated host countries—including countries reliant on tourism revenue.

Noting that largely unvaccinated workers may be expected to come together in large groups to serve vaccinated tourists, Mami Taniuchi, an infectious disease researcher at the University of Virginia, said, "The [infection] risks among vaccinated travelers are significantly reduced, but I worry about the risk of transmission among the people who are working around them."

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She added, "In a situation where there's a mixing of people who are vaccinated and unvaccinated, most of the transmission events are going to be among those who are not vaccinated."

Sarah Fortune, the chair of the department of immunology and infectious diseases at the Harvard T.H. Chan School of Public Health, echoed those concerns. "My doomsday scenario is a mixing of vaccinated and unvaccinated populations in a setting where there is high viral load and high viral transmission," she said. "I think the real danger is that the most vulnerable people are the ones who have the least ability to mitigate risk."

3. Controversial 'vaccine passports'

Some people have suggested that so-called "vaccine passports," or certificates proving an individual's immunization status, could help facilitate international travel. However, the odds of developing an easy-to-use, widely accepted digital certificate in the near future are low, according to the Times.

That's in part because the Biden administration has opted against establishing a centralized federal vaccination database. As a result, any organization attempting to develop such a certificate for U.S. travelers would have to collect immunization status data from a range of state and local registries. More broadly, developing an internationally accepted vaccine passport poses a "multidimensional challenge, involving public policy, public health, consumer experience, and international cooperation," said Eric Piscini, who is overseeing the development of IBM's health passport app, the Times reports.

In lieu of such passports, many people are instead relying on the Covid-19 vaccination record cards that they received when they were inoculated. But such cards are easily forged, the Times reports, available for purchase everywhere from TikTok to Craigslist. And countries such as Greece, which is currently using vaccination certificates or negative test results as a means of verifying tourists' immunization status, "may face both a lack of trust from travelers and pushback from locals who fear that the policies are putting them at risk," according to the Times.

Other organizations, including the World Health Organization (WHO), have come out against the idea of requiring any proof of vaccination for travel. "Quite simply, vaccination is just not available enough around the world and is not available certainly on an equitable basis," Michael Ryan, the executive director of the WHO Health Emergencies Programme, said in March.

4. A different kind of destination

According to the Times, even if U.S. tourists can travel safely, they may be disappointed in the places they visit.

For instance, the Times reports, the pandemic has closed restaurants, museums, and other cultural offerings around the world—plus local curfews come and go in many countries depending on recent case counts. In Paris, for example, restaurants, bars, and museums have been shuttered since October 2020, and curfews effectively shut down the city between 7 p.m. and 6 a.m.

"I really don't know what's going to be attractive to tourists in Paris, now or in the near future," Yumi Kayayan, a travel writer who lives in France, said. "To be honest, the rules are very confusing right now even for Parisians" (Firshein, New York Times, 3/23; CDC guidance, 5/13; Stevis-Grineff/Specia, New York Times, 4/26; Hiltner, New York Times, 5/5).