A series of case reports have suggested that SARS-CoV-2 viral variants may emerge in COVID-19 patients who are immunocompromised due to HIV, cancer, or other conditions, the Washington Post reports.
"The evidence points to these immunocompromised patients as an accelerated cauldron of evolution," David Pollock from the University of Colorado School of Medicine tells it.
The Post notes immunocompromised individuals with COVID-19 typically have longer disease courses, which, in combination with their weakened immune systems, may give variants more time to appear. It points to a number of recent case studies, including one appearing in the New England Journal of Medicine of a man with antiphospholipid syndrome and diagnosed with COVID-19 that says he had "persistent infection and accelerated viral evolution" prior to his death. Another study in Nature describes a man with B-cell lymphoma who exhibited changes in viral variants following treatment with convalescent plasma, suggesting selection for particular variants.
"One lineage would be dominant and then be replaced by another," Pollock says of the Nature study patient. "But then [it would] gain some mutation that made it sort of win more again. So this battle was going back and forth, accumulating mutations."