Paola Bezzon assumed her sniffles in December were just a seasonal cold until a serology test revealed coronavirus antibodies in her blood months later.

Bezzon, 68, lives in Vo’, a town of about 3,300 people west of Venice that was one of the first cities outside of China to experience a Covid-19 outbreak — and the location of Europe’s first Covid-19 death. Researchers arrived shortly after, hoping to learn more about the virus and the human immune response to it.

What they discovered piqued their interest in why some people appear to be immune to the virus long after initial exposure. According to a forthcoming study conducted by researchers from the University of Padua in collaboration with Imperial College London, of the 129 people who still had antibodies nine months after the initial outbreak, 16 had levels that were more than double what they had in May. Among the possible causes of the rise in antibodies is re-exposure to the virus. The study is undergoing peer review.

Vo’s mayor, Giuliano Martini, said virus fighting is woven into the history of the town.

Ships arriving in Venice from plague-infested areas had to wait 40 days – “quaranta” in Italian – before landing in the 14th century. That is how the term “quarantine” came to be.

Venice’s ever-expanding commerce and military forces reclaimed marshy and unproductive land 40 miles to the west two centuries later. Vo’ was born, but it remained largely unknown — more of a transit point between Venetian ports and the Italian inland.

Vo’ registered Europe’s first official Covid-19-related death on February 21, 2020, bringing the relative anonymity to an end. The town was quickly placed under lockdown.

Soon after, Enrico Lavezzo, a professor in the department of molecular medicine at the University of Padua, 20 miles northeast of Vo’, and his team asked the townspeople if they would agree to more testing

Lavezzo, a microbiologist, has since mass-tested the people of Vo’ three times.

“We discovered the presence of antibodies still in late November, nine to 10 months from the initial infection, the longest span of time of antibody presence that had ever been detected during the pandemic so far,” he said.

While so-called super-immunes have been discovered in other parts of the world, it is uncommon for people’s antibodies to increase rather than decrease. Understanding how to elicit such a reaction could be crucial in defeating Covid-19.

“A vaccine is an artificial exposure to a pathogen,” Lavezzo said. “It’s like promoting the immune memory of those who get vaccinated, so next time they get in contact with the virus, their response can be faster and stronger.”

The discovery of super-immunes isn’t Vo”s first study to shed light on the coronavirus. Martini, the mayor, believes the population’s response to testing was motivated by a sense of duty and a desire for redemption.

No one dared to come to the village for months after the initial lockdown, he said, because the community was tarnished by the reputation of “untori,” or plague spreaders.

The local council’s phone line dedicated to assisting the public was becoming overburdened with threatening calls. Vo’ has gained newfound fame as a result of its willingness to participate in studies, which ranges from plague spreaders to a high concentration of super-immunes.

Of 3,300 people in Vo’, around 2,800 participated in the rounds of testing. Raffaella Frasson, 53, will show up for the next one, as well, to see whether, as one of the super-immunes, she continues to have elevated antibody levels.

Because the vaccine rollout in Italy is behind schedule, Frasson is still ineligible for the first dose, and she wishes her antibodies were more useful. Frasson’s antibodies aren’t the only ones being investigated.

Among the information Lavezzo’s team is gathering is a genetic map of the population to see if something in their DNA is helping them fight the virus. That, according to the mayor, could help shed light on the area’s high number of super-immune people. He mentioned that the town’s population is made up mostly of a few families.

Despite Lavezzo’s skepticism, the town’s residents who spoke with NBC News expressed pride and eagerness to see the results. “It’s a mechanism that’s written in our DNA,” Martini explained.