An American man has caught coronavirus for the second time, doctors reported on Tuesday, raising concerns over immunity to the virus.
The 25-year-old man is the first reported case of reinfection in the US, and only the fifth worldwide.
According to a study published in the Lancet medical journal, the man needed hospital treatment after being infected with a stronger strain of COVID-19 than the first time he had it.
Researchers from the Nevada state public health laboratory and the University of Nevada, Reno school of medicine said that the man had tested positive for coronavirus in April this year. He then reportedly tested negative twice, before coming down with the virus again in June after developing symptoms in late May.
“It is important to note this is a singular finding and does not provide generalisability of this phenomenon,” said the lead author of the study, Nevada state public health laboratory’s Mark Pandori.
Doubts over coronavirus immunity
However, the researchers said that further research was required into coronavirus immunity.
“While more research is needed, the possibility of reinfections could have significant implications for our understanding of Covid-19 immunity, especially in the absence of an effective vaccine,” added Pandori.
Immunity through antibodies has been hailed by some as one potential route out of the pandemic.
In line with other diseases, the hope is that patients who have been infected with coronavirus will develop long-term antibodies that resist reinfection, effectively making them immune to the disease.