The prevalence of HIV infection among injecting drug users in the UK appears to be stable, the Health Protection Agency reported last week. Nonetheless, prevalence among newer injectors is rising, with one in one hundred becoming infected within three years of starting to inject.
Compared to other countries, HIV infection among UK injecting drug users has been limited, owing to the early roll out of needle exchanges and other harm reduction programmes. However reports in 2005 indicated that HIV prevalence was rising, and there were suggestions that this could be attributed to changes in policy and service provision.
The Health Protection Agency’s Unlinked Anonymous Prevalence Monitoring Programme’s Survey of Injecting Drug Users is an annual study of over 3,000 current and former injectors. The study is carried out at specialist services such as needle exchanges or methadone treatment programmes in England, Wales and Northern Ireland. Participants complete a questionnaire and provide an oral fluid sample for HIV testing.
Whereas HIV prevalence among survey participants hovered just below 1.0% in the late 1990s, it increased to 1.4% in 2004 and 1.6% in 2005. However the recent data is more encouraging - prevalence appears to have dropped for two successive years, with the 2007 survey finding that 1.1% of users have HIV infection (41 of 3,580 people surveyed).
Nonetheless, the Health Protection Agency is cautious in its interpretation of these trends, simply describing the 2007 figures as “similar to that seen in recent years”.
Moreover, infections amongst people who have recently started to inject remain high. Prevalence amongst people who first injected in the last three years is considered a measure of recent transmission, and remained below 0.5% from 1991 to 2002. However it has risen since then, and is now at 1.0% (5 of 484 people surveyed).
The number of HIV positive respondents who remain unaware of their infection has declined in recent years, with the figure now at 36%. Nonetheless just under a third of the sample has never taken an HIV test (except as part of this study, where they don’t receive the results).
These findings are described in the Health Protection Agency’s annual report on infections among injecting drug users (IDUs). Some of the other key findings from the report include:
- Around one quarter of IDUs reported sharing of needles and syringes. This figure has declined in recent years, following an increase in the late 1990s. The sharing of filters, mixing water, spoons and other equipment is more common.
- Hepatitis C is the most important infectious disease affecting injectors. Almost half have been infected with the virus, and one fifth become infected within three years of starting to inject. Around half of IDUs who have hepatitis C are unaware of their infection.
- One third of injectors report having an abscess, sore or open wound at an injecting site in the last year. Associated bacterial infections include staphylococcus aureus (including community associated MRSA), severe group A streptococci, wound botulism and tetanus.