Conclusions

The search for an HIV vaccine over the last two decades has been a tale of early hopes dashed, followed by the dawning of a more sober optimism.

It is telling that when we wrote about vaccines in the 1990s, the conclusions were mainly devoted to the structural systems that would need to be in place in order to ensure effective access to, and distribution of, an HIV vaccine.

The global discussion now is much more concerned with how to improve and accelerate the process of scientific research and development so that we can get to the stage where even a partially protective vaccine becomes a possibility. Research is currently in a period of retrenchment, with no large efficacy trials currently underway or planned for the near future, as researchers try to understand what kind of vaccine might best induce a truly effective immune response against HIV.

Nonetheless, the rather weak but apparently real efficacy observed in the most recently completed efficacy trial, RV144, has injected a spirit of new optimism into a field that was starting to question whether a vaccine against HIV was even possible. We are now at the tantalising stage of knowing we can stimulate a protective immune response to HIV, but not how to amplify it enough to create a vaccine powerful enough to be useful.

Once a significant candidate proves its worth, the debate on how to best ensure equitable and efficient access will start again, as it has done for HIV treatment, pre-exposure prophylaxis and circumcision.

In the meantime, as with research into vaccines for other diseases such as cancers, the discoveries made en route to a vaccine for a virus as subtle and unusual as HIV are providing science with a wealth of discoveries about immune processes, genetics and viral infections.