是要读原汁原味的科学文章，翻译的都经常出错: People who recover from COVID-19 sometimes later test positive for SARS-CoV-2, suggesting their immune systems could not ward off a second attack by the coronavirus or that they have a lingering infection. A study now hints at a different explanation in which the virus hides in an unexpected place. The work, only reported in a preprint, suggests the pandemic pathogen takes a page from HIV and other retroviruses and integrates its genetic code—but, importantly, just parts of it—into people’s chromosomes. The phenomenon, if true and frequent, could have profound implications that range from false signals of active infection to misleading results from COVID-19 treatment studies. The current study only showed this integration in a lab dish, although it also cites published sequence data from humans infected with SARS-CoV-2 that suggest it has happened. The authors emphasize that their results don’t imply that SARS-CoV-2 establishes permanent genetic residence in human cells to keep pumping out new copies, as HIV does.