I backtracked that Microbiology article to what seems the initial claim of persistence at this article from all the way back in 2020 October. They had 21 people who were rehospitalized (indicating severe disease) and confirmed the second instance was the same viral infection (rather than reinfection), thus a rebound. That's old, though. The Lancet letter notes 9 studies that provided what the authors describe as "conclusive evidence for persistent SARS-CoV-2 infections", and those studies are from 2022 or 2023. At least four of those studies did include people who were known immunodeficient beforehand. (Since SARS-CoV-2 infection itself is known to affect the immune system, that might have something to do with the increasing chance per infection of developing Long Covid, finally reaching a threshold where it establishes permanence.) It calls for more studies, so we have better details about the percent chances and kinds of persistence, since SARS-CoV-2 seems to display all 3 that I've read about: immune privileged organ, syncytial spreading, or immune system compromise.