A bursar from the University of Oxford who spent his 60th birthday in hospital with Covid-19 is taking part in research into treating the virus.
Dr Tim Clayden took antibiotics and donated blood samples for two studies while a patient at the John Radcliffe Hospital.
He said having Covid-19 was "harrowing" and he thought he was dying.
"Even though I was feeling so ill, at least I was doing something positive," he said.
Dr Clayden, who works at Green Templeton College, had an "incredible fever" on 14 March and a week later had breathing difficulties.
He was taken to A&E and tested positive for coronavirus.
Dr Clayden agreed to take part in research and was put on to the Randomised Evaluation of Covid-19 Therapy (Recovery) trial where he was given an allocated antibiotic.
He also supplied samples from home as part of the Coronavirus Clinical Characterisation Consortium study which aims to inform future treatments.
Dr Clayden, whose wife also had Covid-19 symptoms, said: "There was one 3am moment where I thought 'well this is how it happens, you just die'."
"It's so painful, it's sickening and totally debilitating."
Dr Clayden left the hospital on 29 March, a day after his 60th birthday.
"I had different plans but at least my condition was improving and it doesn't get much better than that," he said.
"Going outside in the sun and feeling the breeze changed my life."
There are 15 high-priority coronavirus studies at Oxford University Hospitals NHS Foundation Trust funded by the National Institute for Health Research.
Chief investigator Peter Horby said there was an "urgent need for reliable evidence" into the virus, and trials like those Dr Clayden took part in were the "best way" to get it.