A 72-year-old patient was infected for an unprecedented 613 days, during which the virus mutated into a new variant within his body.

While the global community finds some relief with COVID-19 not dominating daily life as it once did, questions about its return and the long-term effects of the disease remain prevalent. Throughout our series, you will find everything you need to know about the coronavirus pandemic.

The term "long COVID" has acquired a whole new meaning following the latest case report by researchers at the University of Amsterdam. Typically, long COVID refers to the persistence of symptoms after a patient has recovered from the infection. However, the case of a Dutch man who remained infected for nearly two years, totaling 613 days, presents an entirely different story, as reported by IFLScience.

According to the researchers, this represents the longest recorded infection to date. The virus had enough time within the patient's body to evolve into a new variant.

The 72-year-old had previously undergone a stem cell transplant to treat his blood cancer and was later diagnosed with diffuse large B-cell lymphoma, another form of cancer. The treatment for this significantly weakened his immune system. He contracted the coronavirus in February 2022 and was treated with a combination of monoclonal antibodies and steroids. Despite these efforts, the infection became persistent. Even after multiple vaccinations, his body did not produce antibodies.

The man was ill for a total of 613 days, during which he was hospitalized several times. Interestingly, signs of mutation in the virus were detected as soon as 21 days after infection.

Sequencing revealed that the mutations in the virus found in the man were associated with one of the drugs used in his treatment. Between February 2022 and September 2023, a total of 27 coronavirus tests were conducted, revealing an additional 50 mutations. These included mutations in the spike protein, indicating the virus had adapted to evade the immune system.

Given his underlying health conditions, this meant the man's body never had a chance to clear the virus. However, there is no evidence to suggest that the mutation infected anyone else.

The man died in October 2023, due to a recurrence of his primary illness.

Although this is the first case of such an extended period of COVID-19, earlier research had indicated that in 3 out of 100 patients, the infection could last longer than a month.

The case will be presented in more detail at a medical conference in September by the university researchers.