A 72-year-old from the Netherlands was infected with COVID-19 for 613 days, the longest period of infection ever recorded.
Dutch researchers have reported the case of an immunocompromised man, who was infected with the virus for so long, a new variant evolved inside his body.
The man sadly died of a blood disorder relapse while still infected with COVID-19, the researchers said.
"The case is the longest-known COVID-19 infection to date", PhD candidate Magda Vergouwe said.
Several COVID-19 cases lasting hundreds of days have been previously recorded.
The patient was admitted to Amsterdam University Medical Center in February 2022 with a SARS-CoV-2 infection.
The man's immune system had become compromised after a stem cell transplant, which depleted the immune cells that usually fight COVID-19.
Vaccinations and treatments failed to prevent or cure his case of the virus.
Where healthy patients can clear the virus within days, immunocompromised people can develop persistent infections.
DNA sequencing of the virus showed it had become resistant to one form of treatment called sotrovimab.
The man died after "a relapse of his haematological condition", but had retained a high viral load for 613 days.
The man did not pass on the new, drug-resistant variant of COVID-19 to anyone else before he died.
The scientists said "the case highlights the potential for new COVID-19 variants to arise in immunocompromised patients with very long infections".
"We emphasise the importance of continuing genomic surveillance of SARS-CoV-2 evolution in immunocompromised individuals with persistent infections given the potential public health threat of possibly introducing viral escape variants into the community," they said.
"The duration of SARS-CoV-2 infection in this described case is extreme, but prolonged infections in immunocompromised patients are much more common compared to the general community".
