Unlinked anonymous monitoring of HIV prevalence in England and Wales: 1990-92.

Unlinked anonymous surveys are being conducted on accessible sentinel populations in order to monitor the prevalence of HIV infection in England and Wales. These populations have been selected either because of, or regardless of, their risks for HIV infection. Results are presented for specimens collected between January 1990 and July 1992 from 41,461 genito-urinary medicine clinic attenders, 5394 injecting drug users, 296,396 antenatal clinic attenders, 49,009 neonatal dried blood spots, and 32,796 hospital patients aged 16 to 49 years. The prevalences of HIV infection in persons attending two genito-urinary medicine clinics in London, and who were not known to have injected drugs, were 21% for homo/bisexual men, 1% for heterosexual men, and 0.6% for heterosexual women. At four clinics outside London, the corresponding prevalences were 5%, 0.3% and 0.2%, respectively. Of the homo/bisexual men who were found to be HIV infected by unlinked anonymous testing, 26% (229 out of 872) had presented with an acute sexually transmitted disease. Six per cent of male and 6.5% of female injecting drug users attending centres in London in 1991 and 1992 were infected with HIV compared with 0.8% of male and 0.4% of female injecting drug users elsewhere. The HIV infection rate was five times higher in injecting drug users who had had a previous HIV test (2.7%) than in those never previously tested (0.5%). In antenatal clinic attenders in London, HIV prevalence was twenty times higher than in pregnant women elsewhere (0.21% vs 0.01%) but there was considerable variation in prevalence between individual centres. A comparison between unlinked anonymous data and OPCS data for the 15 London centres suggested that the fraction of HIV prevalence in pregnant women at each centre attributable to the proportion of births to mothers born in Africa was between 20% and 100%. However, much of the variation in prevalence was unexplained, so that firm conclusions cannot be made about this relationship. The survey of neonatal dried blood spots showed HIV prevalence in South-East London to be 40 times the rate outside London. The prevalence of HIV infection at two London district hospitals in patients aged 16 to 49 years, from specialties which usually deal with illness not known to be associated with HIV infection, was 0.6% for men and 0.2% for women.(ABSTRACT TRUNCATED AT 400 WORDS)