A woman who survived cancer was infected with the novel coronavirus for nearly a year, in the longest-ever reported case of COVID-19, according to a new study.
The 47-year-old woman was first hospitalized with COVID-19 in spring 2020 at the National Institutes of Health (NIH) in Maryland, Science Magazine reported. Her infection continued for 335 days and was tracked through repeated positive COVID-19 tests and lingering symptoms that required supplemental oxygen at home.
Though her tests showed up positive, virus levels in her body were barely detectable for months after her initial infection. Then, in March 2021, her virus levels spiked again. Researchers compared the genomes from samples collected during her original infection with the more recent one and found that the virus was the same. In other words, this patient wasn't reinfected, but had continued to harbor the same virus for almost a year, the authors reported in a study posted as a preprint on medRxiv, which has yet to be peer-reviewed.
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The novel coronavirus was likely able to remain so long in the woman's body because she had a compromised immune system due to previous treatment of lymphoma, a cancer in part of the immune system, Science Magazine reported. The patient had been successfully treated with CAR T-cell therapy about three years ago, which weakened her immune system by depleting her body of most of its B cells, immune system cells that make antibodies.
There have been sporadic reports on immunocompromised patients who shed the virus for much longer than expected, such as a patient with leukemia in Washington who shed the virus for 70 days, but this is the longest reported case.
Cases of infection in patients with weakened immune systems "give you a window on how the virus explores the genetic space," senior study author Elodie Ghedin, a molecular virologist at the NIH, told Science Magazine. By analyzing samples from this patient and other people with chronic infections, researchers can see how the virus evolves.
In the coronavirus that was sampled from the patient with lymphoma, the researchers found two genetic deletions (a mutation that erases parts of the genome), one in some of the genes that code for the virus's spike protein (the arm the virus uses to invade human cells) and the other, a huge deletion outside of the spike protein — an area that's largely unknown due to lack of study. Other researchers had discovered a similar deletion in that area outside the spike protein in patients with chronic infections, Science Magazine reported.
Chronic infections are rare, but they can lead to new variants, as the virus has more time and space to evolve within a body with a weakened immune system. The patient with lymphoma, who was hospitalized again and treated for the COVID-19 infection, finally cleared the virus and has had multiple negative COVID-19 tests since April.
Read more about the case study at Science Magazine.
Originally published on Live Science.