An 89-year-old woman in the Netherlands has become the first known person to die from catching COVID-19 twice, CNN reports. The woman notably had a compromised immune system due to therapy she was receiving for her rare bone marrow cancer, but researchers said her natural immune response still could have been "sufficient" enough to overcome the disease.

The woman was initially hospitalized for COVID-19 earlier this year, but released after five days with no symptoms except "some persisting fatigue." Fifty-nine days later, she once again tested positive for COVID-19, and no antibodies were detected in her blood; she died two weeks later.

The case is the first known in the world that a person has died after contracting COVID-19 for a second time. However, a number of people have now been confirmed to have contracted the disease more than once, leading to questions about the lasting endurance of immunity.