Bone marrow transplant. All the infected cells die, and the transplant produces new one, free from HIV an. carrying a mutation preventing them from being infected. This approach does not scale.

HIV treatments prevent replication of cells infected by HIV such that the number of immune cells infected by HIV can be undetectable. The problem is there are latent reservoirs of HIV DNA / cells that may reactivate later or hide in areas of the body without immune protection (this is a lot easier for immune system cells with privileged access!). See https://www.nature.com/articles/nrmicro.2015.5 for an older but good discussion on this.

From what I know (which is very little though I follow the news with excitement) HIV is "suppressed" by making it untestably low, which means (apparently) that you are also not contagious. IIRC, therefore maybe you are a carrier, but you experience no symptoms, will not develop AIDS, cannot be proven to be a carrier via testing, and are not contagious. Good enough.

However, in this particular treatment, it was via bone marrow donation, so it literally did change the DNA / body.

From the article:

> For almost six years they’ve tested his blood and other tissues and found no signs of the virus.

Afaict, the researchers themselves don’t know for sure why this has happened.