A travel-safety guide for vaccinated people: How to keep your stress level and infection risk low this summer

• As people begin to travel more, there are ways to fly safely without going overboard, experts say.
• Flying is relatively low-risk for vaccinated people, even in crowded airports.
• It's no longer critical to social distance on planes, but keep your mask on and minimize layovers.

Christopher Sanford was eager to hop on a plane after getting vaccinated in January. Until that point, he had only flown once in the pandemic - to visit his mother in Texas.

"The whole world has cabin fever, and everybody wants to travel now, myself included," Sanford, an associate professor of global health at the University of Washington, told Insider.

So three weeks ago, Sanford and his wife headed to Turkey, alongside a multitude of travelers embarking on their first flights in more than a year.

In the last two months, the average number of daily passengers recorded by the US Transportation Security Administration has risen 30%, from around 1.2 million in March to 1.6 million in May. Booking Holdings, a travel company that owns search engines like Priceline and Kayak, reported that its airline tickets sales jumped 49% during the first three months of 2021.

This uptick came as several countries reopened their borders to tourists: Iceland and Croatia have lifted quarantine requirements for US travelers, for example, as long as visitors show proof of vaccination. The European Union, meanwhile, expects to allow fully vaccinated Americans to visit this summer.

But Sanford said many of his patients still question whether traveling is safe - particularly as airports get crowded.

"I'm very heartened that things are slowly lurching back toward normal, but there's a tremendous amount of fear, even after people have been vaccinated," he said.

He offered a few tips for staying safe while flying, even if you're vaccinated.

Flying was fairly low-risk even before vaccines

The Centers for Disease Control and Prevention recommends that people delay all travel until they're fully vaccinated.

But scientists haven't documented many cases of coronavirus transmission on flights, most likely for two reasons: Airplanes have strict mask requirements and solid air-filtration systems.

Air generally comes in through vents above your seat, then exits an aircraft through floor-level vents nearby, meaning it doesn't circulate throughout the entire cabin. It's also filtered through high-efficiency particulate (HEPA) filters, which can remove coronavirus aerosols (tiny airborne particles produced when people talk or exhale).

"If somebody is right next to you and they have COVID and they take their mask down, that elevates your risk," Sanford said. "But if they're several rows back, even if they don't wear a mask and they have COVID, probably their exhaled air is going to go through a filter before you breathe it in and the risk then would be very low."

A November study found that the rate of in-flight coronavirus transmission was just 1 case per 27 million travelers. By comparison, the rate of fatal car crashes in the US is around 12 deaths per 100,000 people.

Keep your mask on as much as possible

Aside from getting vaccinated, masks are still our strongest defense against transmission on planes, Sanford said.

A September review found no secondary COVID-19 cases on five Emirates flights with up to 2,000 passengers in total. That's despite the fact that 58 passengers on the flights had tested positive for the coronavirus. The researchers attributed the lack of transmission to the airline's strict masking protocol.

Put simply, "the more you wear a mask, the better - the less, the worse," Sanford said.

Book a nonstop flight

The riskiest parts of traveling, Sanford said, are the steps leading up to a flight: cramming into buses that take you to a terminal or mixing with crowds as you wait to board. He recommended asking a friend to drive you to the airport, then finding a relatively isolated location to post up at your terminal.

If possible, he added, opt for a nonstop flight.

"The more stops, the more people, the more airports, the more mixing," Sanford said.

Each of these elements increases your risk of infection - even if that risk is slim.

For short flights, eat before you arrive

US airlines and airports still require masks until at least September 13. But travelers can take off their masks while eating or drinking. That doesn't necessarily mean you should, though.

Sanford recommended keeping your mask on for the entire duration of a short flight, which would require eating before you arrive at the airport. For longer flights, like Sanford's recent 13-hour trip from San Francisco to Istanbul, you'll probably need to eat and drink, though.

"If you're doing a seven-hour flight, it's not good not to drink water for seven hours," Sanford said.

No need to put your mask on between bites, he added.

Seat selection doesn't matter much

Research indicates that blocking off middle seats on planes can lower the risk of transmission on board.

An October preprint, which has yet to be peer reviewed, found that the chance of a passenger in coach contracting COVID-19 on a two-hour domestic flight was 1 in 3,900 if all seats were occupied. But when middles seats were kept empty, that risk went down to 1 in 6,400.

As of May, however, US airlines are no longer blocking off middle seats.

As far as other seating choices go, Sanford said there isn't much data to suggest that window is better than aisle or vice versa. The research so far is mixed: One December study found that the coronavirus' secondary attack rate on a domestic flight in Australia was greater among passengers in window seats than in aisle or middle seats. But other studies have found that people in aisle seats have more contact with other travelers during flights, which can increase their risk of infection.

"Things like seat selection have such a negligible, minimal effect on the ultimate risk," Sanford said.

Splurging on a first-class ticket won't reduce your risk

Although seats in first class are spaced farther apart, Sanford said that probably won't cut your risk of infection.

"I don't think it's a huge difference and I would not spring for the money," he said.

Indeed, a study last year documented an instance of coronavirus transmission in business class. A 27-year-old woman passed the virus to 12 other business-class passengers during a 10-hour commercial flight to Hanoi, Vietnam. The people at highest risk of infection were those less than two seats away from the woman.

Just two passengers in economy class were infected.

Don't travel to a place where the hospital system is overwhelmed

The CDC advises US residents to avoid travel to 140 counties, including those in the European Union. But the agency has suggested that it might be safe for fully vaccinated Americans to travel internationally - with the caveat that they may be at increased risk for getting and spreading variants.

Sanford equated the CDC's message to "a tepid thumbs down" for international travel. The key concern about traveling abroad, he added, is whether you'd be able to receive proper medical care at your destination.

"It'd be really bad for you and all concerned if you got COVID in India currently, with the healthcare system there full of patients already," he said.

Still, Sanford added, there's no need to worry about whether the airport you're flying into has lots of international travelers.

"I don't tell people to avoid international hubs," he said. "I do tell them to avoid crowds."