What of those who are HIV-negative and at risk? Many will want to participate, for obvious reasons, but some will not.

Arguably the biggest obstacle to participation in vaccine research is that it means people facing up to the risks that they are running.

At a practical level, it means taking an antibody test and acknowledging the possibility of being HIV-positive.

It might mean identification as a person at particular risk of HIV, and so being linked to people from whom you would prefer to keep a psychological and social distance. A small-scale interview study of gay men in France who declined to take part in vaccine trials found this to be their dominant problem (Giami). This contrasted, however, with Brazilian studies where the dominant reasons for not participating were given as concerns about side-effects and lack of credibility of a vaccine product (Silva).

However, one of the fundamental problems with being HIV-negative and at risk is that being HIV-negative is a ‘non-status’. Like virginity, it cannot be aspired to, only lost. Prevention of HIV by methods other than vaccination never succeeds for longer than ‘the time being’. For people who are HIV-negative, vaccines offer the possibility of acquiring a status as a ‘protected person’ which they could work towards for themselves or for others.