One in three of all HIV cases in the United Kingdom remained undiagnosed in 2004, up from around one in four in 2003, according to data released today from the Health Protection Agency (HPA). The HPA's annual report, Mapping the Issues, says that of the estimated 58,300 people living with HIV in the United Kingdom at the end of 2004, 38,600 had been diagnosed and approximately 19,700 were unaware of their infection. The report also provides the latest breakdown of new HIV diagnoses during 2004, and an overview of the UK's sexual health.
This includes the following headline data:
- In 2004 there were an estimated 58,300 (range: 54,700 - 63,400) people living with HIV in the United Kingdom, of whom 19,700 (range: 16,100- 24,800) were unaware of their infection.
- During 2004, a total of 7275 new HIV diagnoses were reported in the UK, a small increase from the 7217 diagnoses in 2003.
- A total of 42,182 HIV-positive individuals accessed treatment and care services in the UK during 2004, a 14% increase since 2003.
- The number of diagnoses of HIV infections acquired through heterosexual contact remained high; in 2004 three-quarters of these were probably acquired in Africa. However gay and bisexual men still account for the overwhelming majority of infections acquired in the UK.
- Previously undiagnosed HIV prevalence among UK-born heterosexuals attending key sexual health clinics in London rose to 0.5% (one in 200) in 2004, from 0.3% (one in 333) in 2003.
- In 2004 in England and Scotland an estimated 0.1% of women had an undiagnosed HIV infection prior to antenatal testing.
- The year on year increase in the uptake of voluntary confidential HIV testing among all attendees at key sexual health clinics in the UK continued in 2004, reaching 79% and 75% among gay/bisexual men and heterosexuals, respectively.
New diagnoses
New diagnoses can include people who have been infected for some time as well as those more recently infected.
Just under 59% (4287) of new diagnoses in 2004 were in heterosexual men and women, three-quarters of whom were likely to have acquired their infection in Africa.
The HPA's Dr Barry Evans notes, “While there has been a levelling off in the number of diagnoses likely to have been acquired through heterosexual sex in Africa between 2003 and 2004 (from 3457 to 3138), there has been a slow but steady rise in the number of heterosexual infections acquired in the UK in recent years, from 227 diagnoses in 2000 to 498 in 2004."
Gay and bisexual men accounted for 30% (2185) of new diagnoses in 2004, three-quarters of whom were likely to have acquired their infection in the UK. This is the highest number since 1990. However, since other lab tests suggest that the rate of new infections in gay and bisexual men has remained constant, this increase may be due to increased uptake of voluntary confidential HIV testing, as well as improved methods of reporting.
Undiagnosed HIV infection
Heterosexual transmission accounts for the increase in the numbers of undiagnosed HIV infections that have occurred since last year.
The prevalence of undiagnosed HIV amongst gay and bisexual men attending 27 key sexual health clinics throughout the UK fell from 3.6% in 2000 to 3.5% in 2004. However, across the UK, undiagnosed HIV prevalence amongst gay and bisexual men varied from 4.7% (almost one in 20) in London, to 2.5% in Scotland and 2.4% elsewhere in the UK. The highest levels of previously undiagnosed HIV infection were seen amongst gay and bisexual men born in the Caribbean and Central and South America.
Among heterosexuals attending the same key sexual health clinics, prevalence of undiagnosed HIV increased from 0.3% in 2000 to 0.5% in 2004. In London, undiagnosed HIV prevalence rose from 0.6% in 2000 to 0.8% in 2004. In Scotland, undiagnosed prevalence doubled from 0.1% in 2000 to 0.2 in 2004. Undiagnosed prevalence almost tripled elsewhere in the UK from 0.1% in 2000 to 0.4% in 2004.
The HPA reports says these rises can be partially explained "by the recent dispersal of migrant populations from countries with high levels of HIV infection to areas outside London." The highest levels of previously undiagnosed HIV infection were seen amongst those born in sub-Saharan Africa.
The prevalence of previously undiagnosed HIV infection among UK-born heterosexuals may be used as an indicator of HIV transmission among heterosexuals within the UK. Although figures remain stable in Scotland, in the rest of the UK undiagnosed HIV prevalence amongst UK-born heterosexuals has increased to 0.3% among men and 0.2% among women. The bulk of this rise occurred in London where undiagnosed HIV prevalence rose from 0.3% in 2003 to 0.5% in 2004.
The report's authors suggests that the state of the UK's sexual health is in "a worrying situation with undiminished and high levels of transmission of HIV and other sexually transmitted infections (STIs) among men who have sex with men (MSM), a steady increase in the number of HIV-infected black Africans in the UK, limited but compelling evidence that heterosexual transmission of HIV within the UK is slowly rising, and continuing high transmission of other STIs, especially chlamydia among young people."
"It is essential that prevention messages are reiterated particularly to young people, MSM and to people residing in the UK who originate from HIV endemic areas", they add. The messages should be:
- always use a condom with a new or casual partner.
- make sure you have a check up if you have put yourself at risk of acquiring a STI or have any symptoms.
- think about the possible risks before you have a new sexual partner.
The report concludes with a call for "improvements in access to sexual health services, expanded availability of HIV testing and chlamydia screening, continued work to increase case finding for people with HIV, and focussed prevention interventions for HIV and STIs with groups at increased risk."
The full report can be downloaded from the HPA website.