HIV-INFECTION IN INJECTING DRUG-USERS ATTENDING CENTERS IN ENGLAND AND WALES, 1990-1991

Objective: To monitor trends in HIV infection and associated risk beha viours in injecting drug users (IDU) in England and Wales. Design: Ong oing voluntary unlinked anonymous cross-sectional survey. Method: IDU attending centres in 1990 and 1991 were invited to complete a brief qu estionnaire requesting demographic and behavioural information, and to provide a saliva sample to be tested for antibodies to HIV and to the core antigen of hepatitis B virus (HBV). Results: In 1990, 1.2% (19 o ut of 1543) of samples from 33 centres, and in 1 991 1.8% (25 out of 1 41 7) of samples from 37 centres contained antibody to HIV. Antibody t o HBV core-antigen was found in 33 and 31% of IDU in 1990 and 1991, re spectively. The prevalence of HIV infection in IDU attending centres i n London (4.2%) was higher than in those attending centres elsewhere ( 0.8%). The prevalence of HIV infection in 1991 varied between individu al centres from 0 to 10.6%, and at many centres outside London no IDU were infected with HIV. In the same year the prevalence of past infect ion with HBV varied from 14 to 54%, and IDU who had evidence of HBV in fection were found among attenders in nearly all centres. The prevalen ces of sharing injecting equipment and risky sexual behaviour were hig h at many centres. The prevalence of HIV infection was higher in IDU w ho had started to inject in 1985 or earlier, than in those who started injecting later. In each year, approximately half the IDU surveyed re ported having had a voluntary confidential HIV-antibody test, and the prevalence of HIV infection was five times higher in those tested than in those who had not been tested. Conclusion: HIV prevalence in IDU a ttending centres in England and Wales was low in 1990-1991. There is s ome indication that IDU have modified their injecting or sexual behavi our, but even at existing reduced levels of risk behaviour, transmissi on can occur if HIV is introduced into previously unexposed groups.