A Dutch man was infected with COVID-19 for the longest time, 613 days, until his death in the fall of 2023, according to a study by researchers at the University of Amsterdam Medical Center.

According to Time magazine, the unnamed 72-year-old man already suffered from a blood disorder that compromised his immune system before he contracted Covid-19 in February 2022. Researchers will present the 72-year-old man’s case study at a medical summit in Barcelona next week.

According to Time magazine, researchers found that the virus mutated more than 50 times in his body, eventually transforming into a hypermutated variant.

Researchers said the 20-month duration of the new coronavirus infection is the longest on record, exceeding the 505 days that a British man who died was infected.

Despite receiving multiple doses of the Covid-19 vaccine before becoming infected with the Omicron variant, the patient’s immune system failed to keep up.

Over time, the virus has shown a remarkable ability to resist medical interventions, including Sotrovimab, a well-known antibody treatment for COVID-19, within just weeks of its administration.

The super mutant strain of the new coronavirus has not spread

While the mutated variant did not spread beyond patients, its emergence shows that viruses causing pandemics can undergo genetic changes that create new variants of the pathogen.

“This case highlights the risk of persistent SARS-CoV-2 infection in immunocompromised individuals,” said the authors of the study on this patient.

“We emphasize the importance of ongoing genomic surveillance of SARS-CoV-2 evolution in persistently infected immunocompromised individuals,” the study added.

A case study of the 72-year-old man by researchers at the University Medical Center of Amsterdam will be presented at the ESCMID Global Congress in Barcelona next week.

Research also shows that about 24% of U.S. adults who test positive for Covid-19 have been feeling symptoms for more than three months.