At 25, Troy Kettwick seemed young enough and healthy enough to avoid the worst of COVID-19.

But this spring, the former four-sport high school athlete spent more than three weeks in the hospital, including 12 days on a ventilator fighting for his life after contracting the deadly novel coronavirus.

"It can happen to anybody," said Kettwick, who says he didn't have a history of medical problems. "You don't know if this is something that's going to hit you to the point where there are fatal consequences."

While young adults are far less likely to die from COVID-19 or suffer from a serious illness, doctors and health officials say extreme cases like Kettwick's illustrate how the virus can affect them, even though many won't show symptoms at all.

Among all age cohorts, people in their 20s have emerged as the single largest group testing positive for COVID-19 in Minnesota. They accounted for about 20% of new cases in May, but nearly one-third of new cases — more than 3,400 — from early June to early July.

Kettwick is one of 46 Minnesotans in their 20s who have required intensive care. Two in the age group have died of COVID-19, and neither had underlying health problems, said Kris Ehresmann, the director of infectious disease at the Minnesota Department of Health.

"That's why we keep trying to point out to people that this is not like you can say, 'Oh, this only affects people with blue eyes and I know for certain that my eyes are green and so I don't have to worry,' " Ehresmann said.

"Certainly, we have data that shows us that certain populations are at greater risk, but no population is at zero risk. And by zero risk, I don't just mean zero risk for developing the disease — I mean zero risk for having a really serious outcome."

Beyond general factors, doctors still don't know much about what puts an individual at greater risk for serious illness, said Dr. Ravindra Ganesh, an internal medicine physician at Mayo Clinic who is part of a care team with infectious disease doctors that is focused on treating COVID-19 patients. While many in their 20s who are infected won't have symptoms or develop life-threatening problems, they can spread disease to others, including people who are at higher risk.

"I don't want people in their 20s to feel like they're invincible, because it's not you — it's everybody else that you impact," Ganesh said. "Limit your time around other people. The distance is very important. And then the masks are absolutely protective."

Uptick in young adults

Health officials reported Saturday five more COVID-19 deaths in Minnesota and more than 450 new cases on a volume of 16,492 completed tests. Daily tallies for case counts have been rising in July, but the seven-day trend for new cases shifted lower on Saturday.

Residents of long-term care and assisted-living facilities accounted for three of the newly announced deaths. Statewide, 1,538 people have died from the virus.

The latest numbers show 265 patients were hospitalized, compared with 252 on Friday; 117 patients required intensive care, an increase of seven from Friday. The number hospitalized in Minnesota has been holding steady in July.

COVID-19 is a viral respiratory illness. Those most at risk are those 65 and older, residents of long-term care facilities and people with certain underlying medical conditions ranging from cancer to kidney disease.

But state health officials noted an uptick in infections among young adults last month as restrictions on drinking and dining establishments eased and more people ventured out to bars, restaurants, music events and parties.

In the 20 to 29 age group, 334 of 10,275 cases required hospitalization, according to data released Thursday by the Health Department. The 3% hospitalization rate is much lower, however, than the rate among people 60 to 69, where roughly 1 in 4 are hospitalized.

Allison Seaburg, 28, of St. Paul, tested positive after symptoms emerged in March. The illness started with a sore throat but progressed to chills and shortness of breath.

Months later, Seaburg, an avid marathoner who runs daily and attends fitness classes, says she's still not back to her pre-COVID pace.

"Even if you're a healthy individual, you can still get it and it can still impact you significantly," said Seaburg, who works as a therapist and suspects she was exposed by travel.

Jordann Crowley, 29, of Rochester, said she has no idea how she contracted the virus. She came down with a mild sore throat and cough the weekend of July 4th and had difficulty catching her breath. Symptoms progressed to body aches, headache and loss of taste and smell — one of the odd virus hallmarks for some patients.

"When I got my positive result, I was just frantically telling everyone around me to go get tested," said Crowley, who is better now but staying isolated at home. "My first knee-jerk reaction was: 'I feel horrible.' I mean, it wasn't my fault and I didn't ask to get infected, but you still have this guilt."

'Kind of scary'

Kettwick, an IT recruiter for a staffing firm, also isn't sure how he was exposed.

In late March, his symptoms progressed over a few days to outright fatigue and a fever of nearly 104 degrees. His fiancée drove him to urgent care, where a test revealed pneumonia. She then drove him to United Hospital in St. Paul, where staff donning masks, shields, gloves and gowns met the car outside the emergency room.

Aside from a few minor ailments growing up, Kettwick said he had always been healthy, with no history of diabetes, asthma, a heart condition or other factors that put people at greater risk for COVID-19.

In high school, he competed in football, basketball, baseball and track. In college, he played on a club-level baseball team. He wasn't quite as active in recent years but still played basketball, slow-pitch softball and worked out from time to time.

After two days in the hospital, Kettwick was admitted to intensive care after his breathing worsened. On the third day, a doctor put him on a ventilator.

"It was kind of scary, I think, for all of us," said Dr. Justin Cohenour. "Here's this [25-year-old] coming in otherwise healthy … no previous medical issues, and he's really sick and intubated …

"He could have died. If we didn't have all the makings of modern medicine that we have, he would have died."

After 12 days on the ventilator, Kettwick built up his strength with the help of physical therapy. But even after going home, his heart rate became elevated on daily walks.

Now, three months later, he's jogging and playing softball again, said his fiancée, Rachel Rolling. The couple plan to marry in August but say the happy ending shouldn't keep others from dismissing the risks of COVID-19.

"You've got to take the proper precautions, you've got to be conscious of it, because you just don't know," Kettwick said. "And it's not just you, where you feel like you're young [and] you'll get through it. … You've also got to be conscious of the people around you."