The Wilton man first had symptoms on Thursday, March 12. It started with a scratchy throat and a little bit of a cough, but the cough soon grew worse and he developed a high fever.

The previous Sunday he attended a large family gathering, which included his nephew, Chris Flynn. On Monday he went to a high school basketball game in Westport, which had already become an early coronavirus hotspot after more than 25 people became infected at a party on March 5.

Schools and businesses in Connecticut had not yet shut down and asymptomatic spread was thought to be rare. While it was believed people who were asymptomatic or presymptomatic could potentially spread the virus, that was not thought to be a major way in which it spread.

That appears to be wrong.

“Half the transmission seems to be occurring from people who don’t show any symptoms,” says Dr. Harlan Krumholz, professor of medicine at Yale and director of the Yale New Haven Hospital Center for Outcomes Research and Evaluation. As many as 25 percent of those infected with coronavirus remain asymptomatic and many start shedding the virus in significant ways before they develop symptoms. Krumholz, who has written about the virus for The New York Times, adds, “It makes sense, right, because if you were feeling well at that time you were interacting with a lot of people. If you were sick you tended to separate yourself."

Up until he developed symptoms, the Wilton man continued to work at Rema Dri-Vac Corp., a Norwalk manufacturer he co-owns. His nephew, Flynn, 38, came in close contact with him, and as the man waited more than a week for his COVID-19 test to come back, Flynn continued to work.

“It’s a sneaky virus,” Krumholz says. “If you were going to try to design something that was going to survive throughout an entire population, you might say, instead of hitting everybody hard and putting them out of commission, what you would do is half the people wouldn’t know they have it. So they would be socializing and interacting with other people and spreading it.”

Flynn worked in Rema Dri-Vac Corp.'s office up until March 19, several days before Connecticut shut down all but essential businesses on March 23. (Movie theaters, restaurants, gyms and other higher-volume businesses were shut down a week earlier.) Around the same time, Flynn’s uncle’s test came back: it was positive. Flynn had already carried the virus home. On March 22, 10 days after his uncle developed symptoms, Flynn lost his sense of taste and smell. He experienced severe pain in his nose “and then like behind my nose.” He adds, “by the next day I had a very stuffy nose but with no phlegm or mucus or anything. I had [a nearly] 100-degree fever and maybe a slight cough, maybe just a little tickle-in-my-throat-type cough.”

Today, 2½ weeks after Gov. Ned Lamont issued his Stay Safe, Stay Home executive order, one way the virus is likely still spreading is through households, says Dr. Kevin D. Dieckhaus, associate professor of medicine and chief of the Division of Infectious Diseases at UConn Health. Even with much of the state shut down, “it is still not 100 percent perfect social distancing,” he says. “Because we’re still doing necessary things, going out to the stores for food. We are still congregating in smaller numbers. The smaller numbers might be family.”

Flynn wasn’t able to get tested for five days after he first developed symptoms. It took six more days for the result to come back. Last Thursday, April 2, he learned he was positive. But by that time he had already spread the virus to his family. Flynn’s wife briefly experienced a scratchy throat, and they think she was virtually asymptomatic. Two of their three sons, who are between 4 and 7, had significant but still relatively minor symptoms, and he and his wife believe their other son may have had an asymptomatic case. No one in the family except Flynn has been tested, however.

“If we could completely social distance ourselves from every other human being, if everybody on the globe does that for two weeks or three weeks, and that means a completely biocontained, airtight unit with all your needs being met, this infection would burn out,” Dieckhaus says. “But we’re a society, so there is going to be human interaction. It’s just a matter of degree.”

Dieckhaus adds that the virus is still able to spread, albeit in reduced ways, through cracks in the social-distancing system. “I’m sure there is still community transmission in terms of contamination of surfaces and that sort of thing,” Dieckhaus says.

That doesn’t mean social distancing isn’t helping or saving lives. Over the past five days Connecticut has averaged about 90 new COVID-19 cases a day. That is down from about 102 new cases per day the previous week. Experts see this as a possible sign that social-distancing efforts are paying off and should not be let up.

“There is this lag between an action we take and when we can see the effect of it,” Krumholz says. “The actions that we have taken in this state have been so important in slowing the spread. What we see around the country is the places that have adopted these kinds of approaches have tended to do better than the places that haven’t.”

As for Flynn's uncle, he still has extreme fatigue but hasn’t had a cough or fever for more than a week. Flynn’s symptoms never developed beyond a slight fever and he and his children are doing well, though he and his two sons who developed symptoms are yet to fully recover. Flynn’s senses of taste and smell, for instance, haven’t returned.

* The original version of this story included the name of Chris Flynn's uncle, whose name we removed at his request.