Vaccinated and unvaccinated Americans have different attitudes about the idea of traveling this spring, according to the findings from a marketing technology company. And they’re not different in the way you might assume.

With travel bookings surging, data from New York-based Zeta Global indicates that unvaccinated Americans appear more comfortable traveling — and to more densely-populated places — than vaccinated people.

Zeta Global conducted a survey of 3,700 U.S. consumers in mid-March and combined the results with information on those respondents’ hotel and airport visits in February and March.      

In the survey, 67% of vaccinated respondents said they will not travel until the end of May, but only 59% of unvaccinated Americans indicated they would wait that long. 

More than 80% of vaccinated people who took the survey said they were concerned about the public health restrictions in place at intended destinations, compared with only 38% of unvaccinated travelers who shared that concern.

It’s possible that vaccinated people feel more comfortable traveling when there are health restrictions in place, while unvaccinated travelers are more interested in how local restrictions will limit their trip, said David Steinberg, Zeta Global’s CEO.

The survey indicated that 62% of unvaccinated travelers are “not at all” concerned with public health restrictions at their travel destinations, while only 19% of vaccinated travelers said the same.

Zeta Global’s data showed the top destinations for travelers overall in February and March were New York City, Denver, Atlanta, Dallas-Fort Worth, Philadelphia and two cities in Florida — Orlando and Tampa.

However, trends diverged when broken down by travelers’ vaccination status, said Neej Gore, the company’s chief data officer.

“Vaccinated Americans are choosing locations in the Northeast and Midwest,” Gore told CNBC, adding that the unimmunized traveled to places in the South and spots along the West Coast. 

April travel data, however, showed a shift in traveler habits. Unvaccinated people headed to densely-populated cities, while the unvaccinated went to wide open spaces, according to travel data compiled by Zeta.

“Las Vegas is the city with the biggest relative change,” said Gore, referencing data which showed the number of unvaccinated travelers visiting Las Vegas hotels tripled in April from the month prior, while the number of vaccinated visitors decreased there.

Similarly, the number of unvaccinated travelers who went to Florida in April increased (+6%), yet decreased among vaccinated travelers (-16%).

The Florida trends are primarily a result of incoming travel to Miami and Fort Lauderdale, said Zeta Global. Travel there was up 77% for unvaccinated travelers and down 33% for vaccinated travelers.

While the Northeast and Midwest remain popular destinations for vaccinated travelers, “vaccinated respondents are currently traveling more to the Northwest,” said Gore, based on data showing an increase in vaccinated travelers to Oregon, Washington, Montana and the Dakotas.

Trips to those states did not increase among unvaccinated people, except for Oregon, which the company said is mostly owing to increased travel to Portland by both groups.

Adobe’s 2021 Digital Economy Index, which came out last month, showed regional variations in summer travel habits. The report showed Northeasterners are flying less than other Americans, with March flight bookings originating from the region at only 56% of pre-pandemic levels, a number which falls short of booking rebounds originating in the West (63%), South (70%) and Midwest (75%).

Adobe’s research indicates Northeasterners’ flight purchases are more closely tied to regional vaccination rates. For every 1% increase in vaccinations in the Northwest, there was a 3.2% increase in flight bookings, the highest of any region in the United States.

“The Northeast was hit hard in the early days of the pandemic, likely driving residents to self-restrict when it came to things like travel and social interactions,” said Taylor Schreiner, director of Adobe Digital Insights.

The area, however, is densely populated, said Schreiner, so “feasible alternatives for seeing family and friends” exist.

“A large portion of the U.S. population is within driving distance to New York,” he said, which makes “the opportunity cost of not flying lower.”

Harry Severance, an adjunct assistant professor at Duke University School of Medicine, said people who were vaccinated early are more likely to be concerned about contracting Covid-19 and have greater knowledge about the acute and chronic effects of the disease.

“Thus, I suspect that this group would retain a significant concern over contracting the disease, even post-vaccination,” he said.

Severance said that thought process is changing, as evidence demonstrates vaccinated people have “little susceptibility” to Covid-19 infections, and if they do get sick, infections are typically mild with a “significantly reduced capability of further spreading the disease.”

“It is those who are unvaccinated who should be afraid of traveling,” he said.

“Those who are unvaccinated are putting themselves at increased risk if they gather in large groups of likewise unvaccinated persons,” said Severance, “especially if these groups are assembling from across the country, as the risk of being exposed to different Covid variants is increased.”