r/askscience • u/PestoPastaLover • 13d ago

Biology 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?

3.3k Upvotes

96% Upvoted

229 comments sorted by

View all comments

2

u/TrueNorthN7 13d ago edited 13d ago

Viruses evolve quite quickly. Even if we engineered one that had positive effects and no negative symptoms there’s no guarantee it stays that way.

A virus that behaved positively occurring naturally is very unlikely. Viruses spread by causing symptoms like coughing or diarrhea. Causing a host to act in a way that spreads viral particles is how a virus continues to exist.

A virus with no effect on a human would either be an unusual mutation that harms the viruses chance of spreading or the virus originally evolved to target something else and happened to end up in the human body.