HOUSTON, Texas (KTRK) -- The effects of COVID-19 on some individuals has been shocking, like one man who had no pre-existing conditions but needed a double lung transplant.
He and his family took a trip over the summer to Colorado.
"We went hiking at the Garden of the Gods, going from sea level up to 5,000 feet," said 63-year-old Mark Kuitert.
He said he felt perfectly fine, but things changed quickly.
Not long after driving back to the Houston area and returning from vacation, he ended up in the hospital twice.
During his second trip, he had trouble breathing.
"Very difficult. They had me in a wheelchair and on oxygen before my wife had the car parked," said Kuitert.
He went in to the hospital in late June and didn't return home until November.
"I was in bed for three weeks before they ever got me up in a chair, due to me losing my strength and not being able to breathe," he said.
What he didn't know is how badly damaged his lungs had become.
"The fact that even with two lungs, and the damage is so severe that you're literally giving him pure oxygen to breathe, but there's no lung tissue left to absorb it anymore, so he's breathing air in and out, but there's no transfer of oxygen from the air into his blood stream," said Dr. Soma Jyothula from UTHealth and Memorial Hermann.
Kuitert ended up needing a double lung transplant.
"I didn't know that my lungs were that bad," he said.
Doctors say patients with pre-existing conditions can have more adverse effects.
Penn State College of Medicine found when compared to hospitalized patients without pre-existing conditions, patients with diabetes and cancer are 1.5 times more likely to die from COVID-19. Those with hypertension and congestive heart failure are twice as likely to die, and those with chronic kidney disease are three times more likely.
In Kuitert's case, he didn't have any pre-existing conditions, which made his case so unusual.
Once the transplant was done, there were complications.
"When I was having complications, they talked about doing another lung transplant simply for the way the lungs were going. It didn't look like the graft was going to hold," said Kuitert.
Fortunately, things took a turn for the better. He's now back home, breathing well and still gaining his strength. He also got the vaccine and wants everyone to take the virus seriously.
"I don't want to go through that again. I don't know that I'd make it through. I'm still weak, still getting well and if I got COVID-19 again, there's no telling," said Kuitert.
Houston man has double lung transplant after getting COVID-19