So much has changed since the Centers for Disease Control and Prevention announced in April that vaccinated Americans could travel again. As travel returned with a vengeance, so did the highly contagious delta variant of the coronavirus.

On Aug. 9, the CDC reinstated its highest travel advisory tier for popular destinations such as France, Israel and Iceland, joining others like Greece, St. Martin and Ireland. States are bringing back indoor mask mandates and size limits on group gatherings. The CDC still says, however, that fully vaccinated Americans can travel safely within the United States.

So how should travelers feel about their upcoming travel plans? It can all depend on where you are going, how you are getting there and whom you are going with. We spoke with six health experts for their advice.

‘I think it still is okay to consider taking those trips.’

Amber D’Souza, professor of epidemiology for the Johns Hopkins Bloomberg School of Public Health, says not only have rates of the coronavirus increased in the past month, but they also are “headed in a direction where they will be worse next month.” “We do need to be more cautious than we were before because risk of infection is higher than a month or two ago.”

As far as travel goes, “in evaluating now whether to go on trips, if individuals are vaccinated, risk does remain low if you take appropriate precautions,” D’Souza says. “I think it still is okay to consider taking those trips.”

Instead of canceling vacation plans, D’Souza, who is still doing some traveling herself, says travelers can reduce coronavirus risks by wearing masks indoors or in settings when physical distancing isn’t possible and be wary of crowds. D’Souza also recommends traveling in smaller groups, spending more time outside and avoiding travel unless you’re vaccinated.

“For unvaccinated people who are going on vacation, they are susceptible of themselves becoming ill and spreading ailments,” she says.

‘Your decision to travel should be based on whether it is essential or nonessential.’

Do really you need to travel? That’s the question travelers should be asking themselves during the throes of the delta variant, says pathology expert Manoj Gandhi, senior medical director of genetic testing solutions at Thermo Fisher Scientific, a health-care services and software company that produces scientific instruments, including coronavirus tests.

“Travel certainly increases your chance of not only getting covid, but also spreading covid,” Gandhi says. “Your decision to travel should be based on whether it is essential or nonessential.” Of course, everyone’s definition of essential travel is going to be different.

Gandhi says where you travel and how you get there matters, too.

“There’s a big difference if you are traveling in a crowded airplane for 12 hours or going on a cruise ship for seven days, as opposed to going to a national park in your own car,” he says.

Additionally, Gandhi urges travelers to avoid hot spots where delta variant cases are surging, and looking for CDC travel advisories where you are visiting. He suggests getting tested when your trip is over to avoid contributing to community spread at home.

The hyper-transmissible delta variant of the coronavirus has left would-be travelers uncertain. The Post spoke to an expert about how to safely make that call. (The Washington Post)

‘It’s not just the getting there. It’s what you do when you arrive.’

In the debate over flying vs. driving, Katie Passaretti, medical director of infection prevention of health-care company Atrium Health, says taking your own car can help reduce coronavirus risks.

“I do think just by virtue of having contact with fewer people, my recommendation is — if possible — driving is lower risk,” Passaretti says.

However, “it’s not just the getting there. It’s what you do when you arrive,” Passaretti says. “If you take your car, but then you go to packed bars and very crowded settings … you may not have actually reduced your risk all that much.”

When deciding whether to travel, Passaretti encourages you to consider the health status of the people you’re traveling with or traveling to see.

“Weakened immune systems, you’re visiting grandparents, you’re coming from an area at higher risk — all of those kind of play into that risk-benefit analysis in your head,” she says.

‘For international travel, one size does not fit all.’

Anyone looking to travel outside the United States needs to do a risk assessment of their plans, says David Freedman, professor emeritus of infectious diseases at the University of Alabama at Birmingham. That includes looking at the covid-19 situation in the country and region, the vaccination of locals, any visitor vaccine requirements and the kinds of activities a traveler would do on the trip.

The CDC has travel recommendations by destination, and Freedman also recommends talking to travel medicine specialists and checking the site Our World in Data.

“I think my big-picture overview would be: For international travel, one size does not fit all,” he says. A traveler who wants to use public transportation should avoid high-risk countries, for example, he says. Going to bars and nightclubs or packed tourist sites would also be high-risk.

Freedman says even vaccinated travelers should be taking the familiar precautions in light of the delta variant: masking, social distancing, not eating indoors in restaurants and avoiding crowded spaces, even outdoors.

He does not recommend that even vaccinated vulnerable people — including those with active cancer, transplant recipients, people on drugs that suppress the immune system — travel internationally, “where you don’t know what the medical care is going to be like at your destination.”

As for unvaccinated would-be travelers, Freedman calls it “almost a no-brainer.” “I don’t think unvaccinated people should travel,” he says.

‘Prepare for rapid changes.’

Travelers who are going to another country need to be aware that the rules can change before they leave — or once they arrive.

“Prepare for rapid changes,” says Lin Chen, director of the Travel Medicine Center at Mount Auburn Hospital in Cambridge, Mass., and an associate professor at Harvard Medical School. “So many countries are looking at the numbers and then changing travel restrictions or changing their travel requirements. If not every week, it’s every other day.”

She says those who were vaccinated in the United States need to make sure their CDC vaccination cards will be accepted wherever they’re going to avoid any potential problems or needs for extra testing. Travelers should also budget for extra tests, just in case they end up being necessary.

Chen says she would recommend that severely immunocompromised and elderly people, as well as families with unvaccinated children, hold off on travel for now. She has the same advice for anyone who is not vaccinated.

While she says ventilation systems on airplanes are “quite good,” there’s still a lot of risk involved with flying, such as boarding and getting off a plane, standing in immigration lines and picking up luggage at baggage claim.

“I’ve been more worried about the airports,” she says.

Chen says that anyone planning a trip needs to be aware of the importance of being vaccinated and the fresh risks of the more-transmissible delta variant.

“They must consider how to minimize themselves getting infected or bringing the delta variant or other emerging variant to destinations or back to home or to family or the community,” she says. “That remains important.”

‘Think to yourself … would I be able to manage that risk with my kids?’

As director of pediatric infection control at University Hospitals Rainbow Babies and Children’s Hospital in Cleveland, Claudia Hoyen is hearing a lot of variations on the same question lately: Should we go on vacation?

“I think they’re feeling like, ‘Gee, I’ve done everything right with my kids for the last 18 months — I hate to do something wrong at this point,’ ” she says.

She says that last summer, children were more sequestered with their families and wearing masks more frequently. Many of those practices have become less common just as the contagious delta variant has spread, and the number of cases in children has been rising.

“This is a completely different ballgame than where we were last summer,” Hoyen says.

She says families need to consider their risk tolerance and how they would handle it if someone got sick on or after a trip. And families need to make decisions based on what is possible for their children: Traveling on a plane with teenagers who can keep a mask on would be very different from doing the same trip with 2- or 3-year-olds, she says.

“That plane flight might tip you over the edge in terms of feeling like you’re able to keep them safe,” she says.

Attending a big event with crowds is not a great idea for families this summer, Hoyen says, though going to a cabin where it’s possible to prepare food at home or get takeout would still be doable. All of last year’s rules should apply: Avoid crowds, try to stay distanced inside and outside, wear a mask, keep hands clean.

“You really have to pick it apart and think to yourself in each part of what we’re doing, what’s the risk, would I be able to manage that risk with my kids?” she says. “If yes or no, then kind of make changes based on that.”

For international trips, Hoyen says families should consider the health situation in the destination, what kind of health care would be available and how everyone would get home.

While studies are still ongoing for vaccines in children younger than 12, Hoyen says the best thing to do in the meantime is for all the adults and older kids in a family to get vaccinated to protect the ones who are still too young.

“If you feel it isn’t something you need to do for yourself right now, I would hope that you’d take the stance that it’s something you might do for somebody else — and it’s something you’d do for a child in your life,” she says.