When Michael J. Welsh first met a patient with cystic fibrosis, he could hear their harsh coughing before he even walked into the room. He could see the roughly 8-year-old girl struggle to breathe. He could smell the bacteria in her lungs.
“Afterwards was the sobering part, where we talked with my attending physician, my faculty, and he told us she probably was never going to get to her teens,” Welsh said. “As a physician — as I grew into a physician — you want to do something for your patients.”
He still remembers that little girl after 50 years of researching and treating cystic fibrosis. Today, the outlook for a cystic fibrosis patient is much different. Thanks in large part to Welsh’s research, people with cystic fibrosis who would have died before their 20s can live into their 60s. Life expectancy can be up to 80 for babies born now.
In September 2025 he won the Lasker Award for this research. He was also awarded the 2025 Canada Gairdner International Award in earlier 2025. That award is given to just five scientists a year.
Welsh was born and raised in Iowa. As a young student, he attended grade school in a rural schoolhouse with two classrooms. When he was in college — after considering engineering, literature and philosophy — he started to think about going into medicine.
“I was heavily influenced in this by President John Kennedy. I remember as a boy sitting on the floor in front of the television and watching him, listening to him create the Peace Corps, propose that we go to the moon, because it was hard,” Welsh said. “And I was inspired by that. And I had wanted to do something worth doing, and I thought, maybe I'll be a physician.”
He decided to focus on research, partly to see the payoff of discoveries, but also because he enjoyed learning how processes, like the lung’s control of fluid and mucus, worked.
When he started caring for people with cystic fibrosis, much of the treatment was mechanical. One method, called postural drainage, required turning the patient upside down and pounding at their chest to clear their lungs of mucus. Some patients slept in a mist tent to help their lungs. But these addressed the symptoms, rather than addressing the genetic defect that caused CF itself.
That changed in 1989, when technology advanced enough that it could sequence the genome and find the genetic mutation that caused cystic fibrosis.
“I remember huddling around our fax machine, and there, rolling off the fax machine was the discovery of the genetic defect that caused CF, and that was so exciting," he said.
Before the discovery, Welsh was studying how CF impacted the way salt moved across the lungs. After the discovery, Welsh and his team demonstrated that the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein, which comes from the mutated gene, prevents proper creation of the channel that lets salt chloride flow out of airway cells. This causes the build up of mucus in CF patients. Welsh and his team also discovered that if the cells could be cooled down, it would correct the protein.
The team also grouped different types of mutations into several categories of defect, enabling organization of treatment for different subtypes of CF.
The research also led to the drug Trikafta, which makes CF manageable for more than 90% of patients.
Welsh said one colleague shared with him a story about how a CF patient who had been treated for lung infections was able to run in the state cross country meet after receiving treatment.
“From taking care of these people, it's hard for me to tell you how — it's almost unfathomable, almost unbelievable — the way these people's lives have been changed ... I always have high expectations, and I’m always optimistic, but I underestimated this one," Welsh said.
Though the treatment has greatly improved the quality of life and life expectancy for many patients, Welsh is still working on CF research. He hopes to help the 10% of people with mutations that cannot be helped by current medicines, or who have adverse side effects to the medication options.
Speaking to Charity Nebbe in a Talk of Iowa interview after he won the 2025 Canada Gairdner International Award, he said he was incredibly grateful, and that no one does this work alone.
“We're in this environment, this academic setting, and we're working on a problem that's exciting and that can make a difference to human beings, and we get to pass that on to our students,” Welsh said. “It's a celebration. Whenever I hear about someone who's won a prize like this, it makes me smile, because I'm happy. I'm thinking, this is what we do.”
To hear this conversation, listen to Talk of Iowa, hosted by Charity Nebbe. Dani Gehr produced this episode.
