Unlinked Anonymous survey of Injecting Drug Users (IDUs)
Key Points
Aims and objectives
The Unlinked Anonymous Survey of HIV and Hepatitis in Injecting Drug Users (IDUs) aims to measure the changing prevalence of HIV in current and former IDUs who are in contact with specialist drug agencies (e.g. needle exchange services and treatment centres). The programme also monitors levels of risk and protective behaviours among IDUs, as well as the prevalence of other viral infections. The data are used to assess and develop appropriate preventative and health education campaigns, evaluate the impact of such interventions, and to assist in the provision of services for IDUs in the United Kingdom.
Methodology
Survey data have been collected on an annual basis since the programme was established in 1990. The Health Protection Agency works in partnership with over 70 specialist drug agencies in England, Wales and Northern Ireland to gather the survey data, and provides full training, survey materials, and feedback to each collaborating agency involved. Each year, the agencies are encouraged to ask all eligible clients to participate in the survey - an eligible client being a current or former injecting drug user who has not already participated in the survey in the current calendar year. Each eligible client is asked to complete a short questionnaire and to provide a saliva sample using an OraSure™ device. Identifying information is irreversibly unlinked from all samples before testing, ensuring that both the sample and the questionnaire are completely anonymised. Samples are tested for the presence of HIV and Hepatitis C antibodies (signalling current infection), and also for antibodies developed in response to the Hepatitis B core antigen (which can indicate current or previous infection).
In the questionnaire, participants are asked to provide information regarding their HIV diagnosis status (if known), their patterns of drug use (including treatment for drug abuse and participation in needle exchange services) and their sexual behaviour. This information is used to assess the association between risky activities (such as needle sharing) and the prevalence of HIV among IDUs.
Key Points
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The level of HIV infection among IDUs in England and Wales is higher now than at the start of the decade. Currently, around one in 75 IDUs is infected with HIV.
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In 2006, the prevalence of HIV remained significantly higher among IDUs in London (where one in 20 are HIV-infected) than elsewhere in England and Wales.
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Within England and Wales, the largest rise in HIV-infection among IDUs occurred outside of London, with the prevalence rising from around one in 400 in 2002, to about one in 150 in 2006.
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Amongst current IDUs participating in the Unlinked Anonymous survey, the prevalence of hepatitis C has increased since the beginning of the decade - from 33% in 2000, to 42% in 2006.
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Data suggest that the overall prevalence of hepatitis C infection among IDUs has increased in recent years and that transmission levels of the virus remain elevated.
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Overall about one in five IDUs has had hepatitis B infection. The level of hepatitis B among recent initiates (an indicator of recent transmission) increased from 3.4% in 1997 to 10% in 2006, suggesting that transmission of hepatitis B continues, despite availability of an effective vaccine.
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Levels of reported needle and syringe sharing increased in the late 1990s and have remained elevated since then. In 2006, almost a quarter (23%) of current injectors reported sharing injecting equipment with other injectors in the previous month.
IDU Supplementary Data Set
The following file contains all the tables and figures of the Unlinked Anonymous Prevalence Monitoring Programme of Injecting Drug Users (surveillance update November 2007):
UA Prevalence Monitoring Programme of Injecting Drug Users (PDF, 79 KB)Back to Overall HIV Prevalence Page
Last reviewed: 3 March 2008
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