If 'The Undetectables' sound like a bunch of superheroes, working silently to change the world for the better, then maybe - when put in the context of a desire to reduce HIV transmissions - that’s kind of what they are. Becoming undetectable means the drugs have stopped the virus replicating. Apart from the obvious advantages to a positive person's own health, being undetectable greatly reduces the risk of onward transmission of HIV.