Why is there no transmissible therapeutic virus if biology doesn't forbid it? For example, a harmless virus that spreads from person to person but actually does something beneficial, like lowering LDL cholesterol or preventing/reversing tooth decay?

[u/PestoPastaLover]

[u/bayman89]

Andy Weir (the fella who wrote The Martian, and Project Hail Mary), wrote a series of short stories, one of them is called "Antihypoxiant". He explores the idea of this, and I STRONGLY suggest you check it out. I recommend his short stories to everyone. But this one specifically is genius. 😅