Robert Coy has been fully vaccinated for months and was ready to enjoy a vacation with friends after more than a year of uncertainty during the coronavirus pandemic.
"It was one of those things where, you know, we've been going out to places now at that point, maybe for a week or two, but we were able to take off masks, rejoin society, the CDC guidelines kept getting looser and looser and looser," Coy told NBC Chicago. "So I signed up to go [on a trip], it sounded like a great idea after especially, you know, a year and a half of what we all went through together."
So, Coy and five other friends traveled to Provincetown, Massachusetts, where they enjoyed a memorable vacation.
"We were able to go out, have a great time, make a lot of new friends and had really a blast of a trip," he said.
But as they returned, things changed.
"On Sunday night, all of a sudden, texts started pouring in saying that people who had been fully vaccinated as much as I had were testing positive for COVID," he said, including several members of his group of friends.
So on Monday, Coy got a test of his own. Positive.
The group started messaging others from their trip to warn them.
"It was like this crazy influx of texts and it was checking in with people who like if you had a way to contact people that might have been in a different city or somebody checking in and saying, 'Hey, did this happen in your group too?'" he said. "It was everywhere. It was really shocking that with the number of people who also, you know, said, 'We've gone through vaccination, we've been vaccinated for months,' that a lot of people tested positive."
For Coy and many of his friends, the symptoms were mild, which he credits the vaccine for.
"It's like a really nasty cold," he said. "You'll get a bit of a cough, maybe, and you just feel tired and it's not fun, but I will say it's definitely a lot less severe than I would have expected. Had I gotten this last year before I'd been vaccinated... I've seen people go through way, way, way, way worse."
Coy and his friends are not alone.
Also on Sunday, officials announced plans to increase testing in Provincetown due to a recent spike in cases, particularly involving fully vaccinated people.
"The positive cases were identified in individuals presenting with mild respiratory symptoms and were tested for COVID-19," Town Manager Alex Morse wrote on Facebook Sunday. "Overwhelmingly, the affected individuals have been fully vaccinated for COVID-19. The moderate intensity of symptoms indicates that the vaccines are working as predicted."
Morse noted that Provincetown has some of the highest vaccination rates in the Commonwealth, but he encouraged anyone who is not yet vaccinated to reconsider.
"Health officials expect to continue to see a low level of positive cases through the summer in a community such as Provincetown with a seasonal population of approximately 60,000," he wrote. "As we enter a new phase of living with the virus, vaccination remains our strongest defense in preventing serious illness, hospitalization, and death from COVID-19."
While breakthrough cases have been considered rare, they are possible. Experts have said that while the vaccine itself cannot give you the virus, it is also not 100% effective at preventing the virus entirely, though those who receive the vaccine are far less likely to be hospitalized or die from it, data shows.
Just over 2% of COVID-19 deaths in Illinois so far this year have been among fully vaccinated residents, according to state health officials.
A total of 151 people in Illinois have died due to COVID-19 or complications after being fully vaccinated, according to data updated Wednesday by the Illinois Department of Public Health. That figure equates to 2.2% of COVID-19 deaths in the state since Jan. 1, officials said.
At least 563 fully vaccinated people have been hospitalized in Illinois, IDPH said. The state only reports breakthrough infections among those who have been hospitalized or died, IDPH said.
Chicago's Department of Public Health did not immediately respond to a request for comment on breakthrough cases in the city, but the leader of the city's health department said in early May that the rate of infection post-vaccination was low.
Illinois' top doctor said Tuesday that breakthrough cases of COVID-19 in fully vaccinated residents are a "unicorn."
"These vaccines are truly effective," IDPH Director Dr. Ngozi Ezike said. "You know, everyone has heard of a case or two of someone who had a breakthrough infection or breakthrough hospitalization, but it is, that is so far the unicorn, that you need to focus on the people who are not vaccinated, they're the ones filling up the hospital as COVID patients."
A recent surge of COVID-19 cases in certain parts of Illinois have been found in areas of lower vaccination rates, Ezike said.
"There is a very clear connection between where those case rates are growing the fastest and how well that area is vaccinated, i.e. the more highly vaccinated areas are having lower case rates," she said.
She noted that the growing delta variant has a higher transmissibility that impacts more people at a time than previous variants. Within weeks, Ezike said Illinois has seen COVID cases double statewide.
As the delta variant continues to spread, experts are continuing to push for more Americans to get the COVID vaccine. All three of the vaccines currently authorized for emergency use by the FDA, have shown to be largely effective against preventing serious illness and death due to COVID, and all three companies say that their vaccines are showing promise in preventing those outcomes with the delta variant as well.
Still, U.S. health officials have not yet called for booster shots of any of the vaccines.
"We are prepared for booster doses if and when the science demonstrates that they are needed," the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention said in a joint statement last week.
The agencies said that those who are vaccinated are protected from variants, including the surging Delta variant. But they urged Americans 12 and older who have not been vaccinated to do so.
Coy warned others that the "pandemic is still going on."
"It's still possible to contract it even with the vaccination and it doesn't seem that it could really be tied back to any of the specific vaccines," he said.
For Coy, having a breakthrough case hasn't changed his thoughts on the vaccine.
"If this is the worst I have to deal with, the vaccine was definitely worth it," he said.
Coy said he plans to continue following public health guidance and would get a booster shot if one becomes necessary.
"I'll be the first in line," he said. "If there's a way to either protect us more or keep us at least at the level that we're at, I'll be there."