[stenl]

One major issue is the fact that reverse transcriptase, which copies the HIV genome inside the cell, is sloppy and makes lots of mistakes. As a consequence, every viral particle produced is a little different. A drug that targets any given HIV protein to disrupt it, will work on most particles, but there’s always some that carry mutations that allow them to escape. The solution is to treat with multiple orthogonal drugs.

However,a second major issue is what’s mentioned in the movie, that the viral genome integrates into the host genome and can lie dormant for years. So even if you kill off every single viral particle, years later new particles can be produced from the dormant genome.

A third major issue is that HIV specifically infects T cells, which are the very immune cells that are supposed to combat infection. This weakens the natural defenses, and also makes it difficult to create a successful vaccine.

[sytelus]

I would think that once you kill all infected T-cells, yo got rid of all infection?

[kneel]

I doubt a body can completely rid itself of HIV but once you get rid of all infected T-cells you've Acquired Immune Deficiency Syndrome.