As Covid-19 cases surge across the United States due to the delta variant, many people are considering whether to cancel their late summer travel plans. According to public health experts and epidemiologists, the decision should depend on where you're going and what circumstances are like there.

How much worse will the 'delta surge' get? Watch these 7 factors.

How the delta variant has impacted travel plans

According to the Transportation Security Administration, the daily number of passengers screened at airports has decreased by around 30,000 since July, the New York Times reports. However, travel advisers and hospitality companies said the recent decrease in travel bookings is still relatively small compared with the dramatic decline seen last year.

And TripActions, a travel management company, said cancelations for same-week travel have been at 26% over the last month, up from an 18% average before the delta variant increased cases across the country. However, new bookings for domestic travel have remained strong.

The airfare app Hopper has also seen a 33% increase in demand for flexible booking since July, which would allow passengers to cancel their tickets for any reason.

Separately, Scott's Cheap Flights, a travel site that notifies subscribers of airfare deals, recently surveyed its members and found that 74% said the delta variant impacted their travel plans. In addition, 35% said they were not currently booking any new trips, and 24% said they were booking only domestic trips.

"Of those who are booking new international trips, the vast majority are booking for 2022," Andrew Hickey, senior public relations manager for Scott's Cheap Flights, said. "People are also determining where they'll go based on Covid."

However, Zeta Global, a marketing technology company that tracks Americans' travel behavior, found that people's vaccination status has also affected their travel plans. For instance, while travel to Covid-19 hotpots, like Florida, has decreased among those who are vaccinated, it has increased among those who are not.   

What some experts say they would do

STAT News spoke to 28 infectious disease experts about what they personally believe is safe to do this summer, including traveling both domestically and internationally. Overall, the experts said their decision to travel would depend on where they were going and what circumstances were like there.

When asked whether they would travel to a U.S. location experiencing a surge in Covid-19 cases or go on a nonessential international trip, the experts as a group were "slightly more" willing to travel internationally than domestically to areas with high cases, STAT News reports.

Carlos del Rio, a professor of epidemiology and global health at the Rollins School of Public Health at Emory University, lives in Atlanta but frequently travels to Miami to visit his family. "I am very careful when I travel," he said.

In addition, del Rio said that although he visited his mother, who lives in Mexico, twice during the pandemic, he would not do so "at this point," adding that he "[m]ay go later in the year."

Separately, Carl Bergstrom, an evolutionary biologist at the University of Washington, said he wouldn't travel abroad right now—but not necessarily because of Covid-19. Instead, he worried he might get stuck in another country if travel restrictions were put back in place.

Similarly, William Hanage, an epidemiologist at Harvard University's T.H. Chan School of Public Health, said he and his family vacationed at Cape Cod instead of taking a planned trip to Iceland for the same reason.

In contrast, Nahid Bhadelia, director of the Center for Emerging Infectious Diseases Policy & Research at Boston University, said she would not travel to a domestic destination with a high number of Covid-19 cases but would consider traveling internationally if the area she was going had a low transmission rate and a high vaccination rate.

Angela Rasmussen, a coronavirus virologist at the University of Saskatchewan's Vaccine and Infectious Disease Organization, said she would visit a U.S. Covid-19 hotspot but would take precautions while she was there. Regarding international travel, she said it "depends where" and that she would be masked.

And Naor Ber-Zeev, a statistical epidemiologist at Johns Hopkins Bloomberg School of Public Health said his behavior—including whether he would travel domestically or internationally—depended on the specific circumstances at a location.

"In a place where most people are unvaccinated, or otherwise at high risk, and where there is active transmission, I should act more conservatively and with greater caution, even though I am protected from disease," he said. "In a place where most people are vaccinated, and there is low transmission, one can be more permissive." (Kamin, New York Times, 8/20; Branswell, STAT News, 8/17)