according to experts in the United Kingdom.
The man was treated with a mixture of neutralizing monoclonal antibodies, King’s College London said in a news release.
The man, 59, tested positive in December 2020 and tested negative in January 2022. He had a weakened immune system because of a previous kidney transplant. He received three doses of vaccine and his symptoms lessened, but he kept testing positive for COVID.
To find out if the man had a persistent infection or had been infected several times, doctors did a genetic analysis of the virus.
“This revealed that the patient’s infection was a persistent infection with an early COVID variant – a variation of the original Wuhan variant that was dominant in the United Kingdom in the later months of 2020. Analysis found the patient’s virus had multiple mutations since he was first infected,” King’s College said.
The doctors treated him with a Regeneron treatment that is no longer widely used because it’s not effective against newer COVID variants.
“Some new variants of the virus are resistant to all the antibody treatments available in the United Kingdom and Europe. Some people with weakened immune systems are still at risk of severe illness and becoming persistently infected. We are still working to understand the best way to protect and treat them,” Luke Snell, MD, from the King’s College School of Immunology & Microbial Sciences, said in the news release.
This is one of the longest known cases of COVID infection. Another man in England was infected with COVID for 505 days before his death, which King’s College said was the longest known COVID infection.
A version of this article first appeared on WebMD.com.