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LONDON — The case of a man in the United States infected twice with COVID-19 shows there is much yet to learn about immune responses and also raises questions over vaccination, scientists said on Tuesday.
The 25-year old from Reno, Nevada, tested positive in April after showing mild symptoms, then got sick again in late May with a more serious bout, according to a case report in the Lancet Infectious Diseases medical journal.
The report was published just hours after U.S. President Donald Trump, who was infected with COVID-19 and hospitalized earlier this month, said he believes he now has immunity and felt “so powerful.”
Scientists said that while known incidences of reinfection appear rare – and the Nevada man has now recovered – cases like his were worrying. Other isolated cases of reinfection have been reported around the world, including in Asia and Europe.
“It is becoming increasingly clear that reinfections are possible, but we can’t yet know how common this will be,” said Simon Clarke, a microbiology expert at Britain’s Reading University.
