Dozens of summer tourists who were among those visiting the gay resort town of Provincetown, Mass., over the weekend came back with more than beach memories and a tan: They tested positive for COVID-19 — even though they were vaccinated against the disease.

The surprise outbreak among individuals who did their public duty to get vaccinated is taking many observers aback at a time when Americans who refuse to get the shot, despite overwhelming evidence of safety and effectiveness in combatting coronavirus, are facing heavy criticism, which experts say precludes the nation from reaching herd immunity.

Robert Coy, a gay 28-year-old business strategist from Chicago, told the Washington Blade he tested positive for coronavirus on Monday after learning about mild symptoms among housemates during his visit to Provincetown.

“It was just kind of wild,” Coy said. “You went through the whole year-and-a-half of the pandemic and you got vaccinated and do what you’re supposed to do. There wasn’t really any negative pressure against traveling over the Fourth of July for a vaccinated person.”

Coy, who said he was vaccinated in April and is now largely asymptomatic aside from a mild cough, said finding out about the dozens of people who came down with coronavirus after visiting Provincetown despite being vaccinated was “really surprising.”

“Here in Chicago, I think it’s the same in D.C., but people are drawn out here on the dance floor until four in the morning on a Saturday night, and no one has really seemed to be affected,” Coy said. “So the whole experience was kind of unexpected.”

At the same time, Coy said he’s glad no severe cases were being reported and called the breakthrough outbreak “a nice reminder that we’re still kind of learning.”

To be sure, the anecdotal reports of COVID infections among vaccinated people who went to Provincetown doesn’t justify refusing the vaccine. All signs and evidence show COVID-19 vaccines are safe and effective, as medical experts continue to say as they try to convince Americans, many of whom are intransigent against the vaccine, to take their shots.

But the COVID breakthrough cases over a short period of time weren’t insignificant in number and put in stark relief the limitations of the vaccine in fully shielding people from coronavirus, including vulnerability from individuals spreading the disease by refusing shots and fears about the emerging Delta variant.

Kyle Blaine, a White House reporter for CNN, was among the more high-profile individuals who reported having contracted coronavirus after visiting Provincetown over the weekend.

“PSA: If you were in Provincetown last week and have cold/flu symptoms, please get tested for Covid,” Blain tweeted on Sunday. “My husband and I are fully vaccinated and tested positive yesterday. We’re OK — only mild symptoms so far. I know close to a dozen other vaccinated people who tested positive.”

Michael Ahrens, a 32-year-old gay D.C. resident who came down with coronavirus after spending a week in Provincetown, said he initially obtained a negative test result after returning from his vacation, then upon taking a second test Monday out of an abundance of caution tested positive for COVID.

“I think, in that moment, I wasn’t as surprised because I had started hearing about more people testing positive, but I really didn’t have any symptoms, so I was surprised because of that,” Ahrens said. “If you had told me a few days prior, that a bunch of fully vaccinated people were going to be testing positive for COVID, I wouldn’t have believed you.”

None of the coronavirus cases associated with visiting Provincetown appear to be life-threatening. The COVID patients who spoke with the Blade said they had mild symptoms such as fatigue and a mild cough, but exhibited no signs of major illness.

One person, however, said on Twitter in response to a local reporter’s public inquiry for stories he was among the breakthrough cases and had been hospitalized as a result of his condition. The individual didn’t immediately respond by Blade deadline to go on the record and elaborate further on the severity of his illness.

David Hardy, a Los Angeles-based scientific and medical consultant, said the breakthrough infections are “a difficult situation on which to comment due to the imprecise nature of the information available.”

“It would be highly surprising to discover that ‘dozens’ of fully vaccinated tourists (gay or straight) were becoming ill with COVID-19 after visiting P-Town,” Hardy said. “We know that all three vaccines given EUA status in the U.S. reduce the chance of contracting COVID-19 illnesses by 85 percent to 95 percent. Recent data from studies evaluating the new Delta variant becoming more common in the U.S. now show that these three vaccines still protect against COVID-19 illness.”

Hardy added, however, what isn’t known is whether the vaccines “prevent infection with SARS-CoV-2, the cause of COVID-19.”

“Limited data says that the chance of infection is reduced by ~70%-75% after vaccination, which is good but not great,” Hardy said. “Persons with asymptomatic SARS-CoV-2 infection can still transmit the virus.”

A firm count on the number of tourists who went to Provincetown over the weekend and came back with coronavirus would be impossible. After all, individuals could have visited the resort over the weekend, returned home with COVID-19 and gotten their test result elsewhere or never got tested because they remain asymptomatic.

The number of coronavirus cases reported by the Barnstable County Department of Public Health last week was between 20 to 25 and more than half were “short-term visitors,” according to local WBZ reporter Louisa Moller.

Sean Holihan, a gay D.C. resident who visited Provincetown over the July 4th holiday, counted himself on Twitter among almost 30 tourists who came down with COVID as he cautioned against reading too much into the infections.

“Between myself and others, I know of nearly 30 breakthrough cases of Covid that came from visiting Provincetown for the 4th of July,” Holihan wrote. “In each and every situation, the symptoms were mild and no one required a hospital visit. The vaccine works.”

A Massachusetts Department of Health spokesperson said specific cases for Provincetown weren’t immediately available, but “breakthrough case numbers are incredibly low and cases in which the person was hospitalized or died are even lower.”

As of July 10, the total number of breakthrough cases reported to the Massachusetts Department of Health was 4,450 cases out of 4,195,844 vaccinated individuals, the spokesperson said. That fraction is 0.1 percent of vaccinated individuals.

“All available data continue to support that all three vaccines used in the U.S. are highly protective against severe disease and death from all known variants of COVID-19.,” the spokesperson said. “The best way to protect yourself and your loved ones is to get vaccinated.”

Having chosen a gay resort town for a vacation getaway, many of the tourists who went to Provincetown were members of the LGBTQ community and predominantly gay white men. COVID infection in a community that commonly holds progressive views runs counter to the narrative the virus is spreading among Trump-supporting Americans who refuse to get vaccinated despite assurances of safety and the dangers of contracting COVID.

Coronavirus would have ample opportunity to spread among the tourists in Provincetown. Beach parties during the day and club dancing at night, not to mention the close proximity of tourists cramming themselves into group homes to lower costs of their visit, would have been called “super-spreader” events at the peak of the pandemic.

At least one venue was strict about requiring proof of vaccination before allowing entry into the festivities, turning away those without vaccination cards or even cards showing proof of having taken one of two vaccine shots needed for full vaccination. Other venues, however, were lax at a time when Americans would be expected to have vaccinations before gathering in a large crowd and required no proof of immunity before allowing patrons to enter.

Additionally, a ferry tourists commonly use for travel between the Boston airport and the Provincetown resort was cancelled over the weekend due to inclement weather, forcing visitors to cram themselves in crowded buses to get to their destination without open air or social distancing protecting them from infection.

Despite having contracted the disease, the COVID patients who spoke to the Blade said coming down with the disease despite having been vaccinated has done nothing to change their views.

Coy said the coronavirus outbreak may be evidence the restrictions lifted in recent weeks were too many, too quick and more caution should be exercised.

“All the restrictions just kind of ripped away within such a short time span,” Coy said. “I don’t think there was any major caution encouraged as far as going out or as you’re traveling, like continuing to really be vigilant and stay within a small circle of people.”

Ahrens said having come down with coronavirus after receiving his vaccination has done nothing to dissuade him from his belief the vaccine is safe and effective.

“I followed guidance for fully vaccinated people and fortunately people who are vaccinated are having a much easier time fighting off COVID than people who are not vaccinated,” Ahrens said.

CORRECTION: An initial version of this article misspelled the name of Robert Coy. The Blade regrets the error.