I read somewhere efficiency is 10%-20%. That may be fine to fix a condition where you need to add a new protein, e.g. muscular dystrophy. However, maybe not so

I read somewhere efficiency is 10%-20%. That may be fine to fix a condition where you need to add a new protein, e.g. muscular dystrophy. However, maybe not so well where you need to subtract. If you can pose an HIV therapy as the former- say make 10% of the T-cell stem cells infection-proof, then that could work. On the other hand, hoping the remove all the retro-inserted HIV DNA probably wont work.