Evaluation of needle exchange in central London: behaviour change and anti-HIV status over one year.

From November 1987 to October 1988, numbers of clients, visits made and syringes dispensed and returned were monitored at the needle exchange of the Middlesex Hospital, London, UK. A sample of clients were interviewed 1 month after entry to the scheme and again 3 months later to evaluate changes in injecting and sexual risk behaviours for HIV infection. Clients were asked to donate saliva for anti-HIV immunoglobulin G (IgG) antibody capture radioimmunoassay (GACRIA). The rate of lending and borrowing used injecting equipment fell, both compared with rates prior to entry to the scheme and during the period of study. Frequency of injecting did not increase and there was reduced incidence of abscesses. There was a highly significant correlation between multiple sexual partners and condom use and a reduction in the proportion of clients with multiple partners. On entry to the study, seven out of 121 (6%) clients were anti-HIV positive; after 3 months, a further two clients tested were found to be anti-HIV positive. Anti-HIV positivity prevalence for the year of study was nine out of 121 (7%). The scheme attracts clients, reduces injecting-related risk for HIV infection and has high equipment return rates. Saliva testing is acceptable to clients. Continued monitoring of anti-HIV in saliva is indicated.