Despite rising Covid-19 infections throughout the United States, Europe and beyond, people are preparing to travel in late 2020.

According to a survey by travel booking app Hopper, 39% of Americans are expected to travel during the upcoming holiday season. By that estimate, nearly 130 million people will be hitting the road in the United States alone before the end of the year.  

Homebound and weary after a stressful and vacationless year, many in America at least simply aren't willing to miss spending Christmas and Thanksgiving with their loved ones, no matter the coronavirus count.

The CDC on Nov. 19 revised its guidelines, advising against traveling during the Thanksgiving holiday. In a news briefing on the same day, CDC officials advised against celebrating with anyone outside of one's household, including returning college students and family members who live nearby.

But many Americans will be traveling regardless, or have already begun to. CNBC's Global Traveler asked doctors for advice that people can use over the holidays.  

Before leaving home

1.      Find out who is gathering

It's important to understand how much risk a family can tolerate, said Dr. William Lang, a former White House doctor and current medical director of telemedicine practice WorldClinic. Start, he said, by assessing the ages and health of attendees.

"A younger family with all healthy members and no recognized, higher risk factors can accept a little bit higher risk than a multigenerational family where some of the older members have chronic diseases," he said.

A group of younger family members may be able to safely get together, as could a group of older, Covid-cautious relatives. But young people planning to congregate at their parents' and grandparents' homes need to be especially careful.

"Unfortunately," Lang said, "this is not the year for big multigenerational holiday gatherings with family from far-flung places."

2.      Quarantine before the trip

"The only accepted way to virtually eliminate risk is a 14-day strict quarantine," Lang said. "But in most families, that's not practical, and especially with young adults, it probably just wouldn't happen."

He said young adults should, at the very least, minimize social activities — "especially bar-like activities" — in the 10 days before going home.

3.      If possible, drive

Dr. Anne Rimoin, a professor of epidemiology at the UCLA Fielding School of Public Health, said that while data suggests air travel carries minimal risks of contracting the coronavirus, flying "is more than just sitting on a plane."

"You have to go through [security], wait in seated areas and lines to board, and use public bathrooms," she said. "You also cannot control who you sit next to, which also dictates your risk."

Lang agrees that flying is "fairly safe" but that getting through the airport and on and off the plane is riskier. To avoid the "crush in the aisle," he advises passengers to stay in their seats until it's their turn to disembark.

Driving is the safest way to travel right now, said Dr. Diego Hijano, assistant faculty member of the Department of Infectious Diseases at St. Jude Children's Research Hospital.

"Act as if both you and everyone you meet in transit may be infectious, and remain vigilant," he said. "Consider packing all food and snacks for the trip."

4.      Quarantine upon arrival

To reduce risks, wait five days before integrating into the family environment, Lang advised.

Such a wait "reduces risk of an unrecognized infection by about 50%," he said. "And if you add a test to that — at the end of the five days — you can reduce the risk by another 25% or so."

Hijano cautioned that a negative Covid-19 test should not be considered a "fail-safe reassurance that you are not sick." He recommends individuals should quarantine upon arrival only if they think they've been exposed to the virus, in which case "you should immediately cancel the trip."

If that seems excessive, consider it only takes one person to infect the group.

During the stay

Home is a haven for many. But for the safety of everyone, precautions should be heightened, rather than relaxed, upon arrival.

Travelers should wear a mask — even with their own family members, Lang said — and should avoid close contact with at-risk family members, especially when indoors.

Younger people returning to their hometowns often get together with old friends. Lang's advice on that: Don't do it this year. He said that group activities, such as going to bars and parties, should be minimized this season.

"Those are the highest risk types of events," he said.

Advice for holiday hosts

Hosts need "to establish rules ahead of time," said St. Jude's Hijano.

He recommends planning a small gathering for a shorter duration than usual. Avoid hugging and handshakes when guests arrive, he said. Spread tables and chairs apart, and insist that guests wear masks, stay socially distanced, and wash their hands.

"Remember that outdoors is always better than indoors," said Hijano. "If outdoors is not possible, use a large, well-ventilated room and consider opening a window."

The Centers for Disease Control and Prevention advises making holiday gatherings small enough to allow guests to stay six feet apart at all times. Music should be kept low (to prevent people from shouting to be heard), garbage cans should be contactless, and guests shouldn't touch pets, per CDC recommendations.

Serving food, a central part of most holiday gatherings, is complicated. The CDC encourages guests to bring food and drinks for themselves; potluck-style meals are to be avoided.

If food is offered, one person should serve, including sharable items such as salad dressings and condiments. All linens, including seating covers and tablecloths, should be laundered immediately after the event.

Finally, hosts should remind guests to stay home if they are sick or have been exposed to Covid-19, said Hijano.

The safest option? Stay home

It's safer to stay home and share the holidays with people who live in our own household, Hijano said.

This year, he plans to cook a Thanksgiving meal and watch the Macy's Thanksgiving Day Parade with his immediate family, while sharing the events virtually with others.

"It is important to … start having hard conversations now with the people you care for most about the possibility that you might have to stay put and stay apart, especially if you have a family member with risk factors for severe Covid-19," Hijano said. 

"While all of us are tired of connecting online, it really is the safest way," he said.