Apparently, according to the story and the ones which followed up, it was a general assumption that RNA only transcribes (reads) and the original is never altered. (I forget the term off the top of my head) but they found a component of the transcription process (12 RNA polymerase in total) about 3 of them do most of the handling of the RNA transcription procedures.

The scientist found that of these 3 of the process is apparently reversible (read and write) and virus sequences can be written back as DNA sequences. They described that it's always been known that ancient viruses sequences are present in most DNA (20%) but they hadn't fully figured out the mechanisms.

They want to study it further to see if the same mechanism can later be used for gene therapy.

https://www.sciencemag.org/news/2020...what-does-mean

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Separate to that study, "Long Haulers" patients from COVID 19 infections might be a result of specific infected cells having their sequences altered causing an immune response or general dysfunction. Which results in diseases and lingering and persistent illness after the initial infection that are not directly tied to COVID 19.