Covid-19 can strike anyone - including a professor of infectious diseases at the Liverpool School of Tropical Medicine.
Paul Garner gave a blow-by-blow account of his experience of having coronavirus, which put him out of action for seven weeks.
And he warned the symptoms were "frightening and long" and always kept changing.
In a blog written for The BMJ medical journal, Prof Garner said he developed the disease in the middle of March.
He said: "For almost seven weeks I have been through a roller coaster of ill health, extreme emotions, and utter exhaustion.
"Although not hospitalised, it has been frightening and long. The illness ebbs and flows, but never goes away.
"People who have a more protracted illness need help to understand and cope with the constantly shifting, bizarre symptoms, and their unpredictable course."
Prof Garner said his specialised medical knowledge at first assured him he was free from the disease.
He added: "Then one afternoon I started feeling strange. I went home early, and then the journey began.
"In the first days at home I wasn't sure I had covid-19. The heaviness and malaise became worse, I had a tightness in the chest, and realised it could be nothing else.
"I was mortified that I might have infected the staff I had worked with for over 20 years. I imagined their vulnerable relatives dying and never forgiving myself. My mind was a mess. My condition deteriorated. "
As the disease tightened its grip, the professor said at one point he felt so unwell he thought he was dying.
He added: "There was nothing to do. I thought, if this is it so be it."
His condition continued to fluctuate with a series of changing symptoms - including a muggy head, upset stomach, tinnitus, pins and needles, aching all over, breathlessness, dizziness, and arthritis in the hands.
He said: "The internet described recovery times of about two weeks for people that had not been hospitalised.
"I had not had severe disease, yet here I was after four weeks still unwell."
Now that the disease has lifted, Prof Garner said he wanted to get this message out.
"For some people the illness goes on for a few weeks. Symptoms come and go, are strange and frightening," he said.
"The exhaustion is severe, real, and part of the illness. And we all need support and love from the community around us."
