- 25 March - First wave of symptoms, (click here) including sore throat, cough, headache, nausea and diarrhoea
5 June - He tests positive for the second time, and is hypoxic (low blood oxygen) with shortness of breath
"Our findings signal that a previous infection may not necessarily protect against future infection," said Dr Mark Pandori, from the University of Nevada.
"The possibility of reinfections could have significant implications for our understanding of Covid-19 immunity."
He said even people who have recovered should continue to follow guidelines around social distancing, face masks and hand washing....
An otherwise healthy 25-year-old Nevada man (click here) is the first American confirmed to have caught COVID-19 twice, with the second infection worse than the first.
He has recovered, but his case raises questions about how long people are protected after being infected with the coronavirus that causes the disease, and potentially how protective a vaccine might be.
"It's a yellow caution light," said Dr. William Schaffner, an infectious disease expert at the Vanderbilt University School of Medicine in Nashville, Tennessee, who was not involved in the research.
Respiratory infections like COVID-19 don't provide lifelong immunity like a measles infection. So, Dr. Paul Offit, an infectious disease expert at Children's Hospital of Philadelphia, said he's not at all surprised people could get infected twice with the coronavirus, SARS-CoV-2.
