In this article, Simon Noble, editor of IAVI Report, explores the prospects for a kind of HIV vaccine that aims to boost the immune response in people already infected with the virus, rather than what most vaccine researchers are working on, namely to protect against infection in the first place.

The article is written for scientifically educated readers who already have a basic knowledge about vaccines, and lay readers may therefoer find it somewhat technical. Nonetheless, it is a useful account of what many researchers feel is a worthwhile goal. The article reviews the different approaches in designing and testing therapeutic vaccines, and presents the views of different experts in the field.

It also features some of the scepticism around the concept of a therapeutic vaccine, including the concern that the immune system is so impaired by HIV infection, and the virus already so diverse after multiplying millions of times in the body, that it may not be possible to mount a stronger and more effective immune response against the virus.