Unlinked Anonymous Survey of Genitourinary Medicine Clinic Attendees (GUM Anon Survey)

The GUM Anon survey is the only large scale survey in the UK to provide information on the prevalence of HIV, including undiagnosed HIV amongst GUM attendees. It uses the unlinked anonymous technique on left-over specimens taken for routine syphilis tests.

HIV Prevalence Overall prevalence of HIV infection, including undiagnosed HIV infection, and associated risk factors among GUM attendees

HIV test uptake and outcome the uptake of HIV testing in GUM attendees and the fraction of previously undiagnosed HIV positive GUM attendees remaining undiagnosed after a visit

Recent HIV infection amongst men who have sex with men (MSM) attending GUM clinics, calculated using the STARHS algorithm

GUM Anon Summary 2008 (update 2009) (PDF, 76 KB)

Summary of GUM Anon findings by Prevention Group 2008 (update 2009)

• Men who have Sex with Men (MSM)
• Black African and black Caribbean communities
• Young adults
• HIV data: Injecting Drug Users 2009
  

Annual Reports 2005/2009

HIV and STIs 2005/2009 Reports

Related Topics:

• HIV and Other Sexually Transmitted Diseases in the United Kingdom
• Surveillance systems at CfI
• Other HIV Data 

Methodology                   

UA GUM Ethics

Contacts

Methodology

The GUM Anon survey uses the unlinked anonymous technique on left-over specimens taken for syphilis tests to measure the HIV prevalence amongst all GUM attendees, including those not having voluntary confidential HIV testing.  The unlinked anonymous technique involves removing all identifying information from the specimens.  Limited information on risk factors and whether voluntary confidential HIV testing was accepted is retained.  This survey is operational in 16 GUM clinics across the UK (eight in London, one in Scotland and seven elsewhere in the UK).

The Serological Testing Algorithm for Recent HIV Seroconversion (STARHS) is a laboratory technique that has made it possible to identify infections that are likely to have been acquired within a well defined period of time as a key indicator of HIV transmission.  The STARHS technique is applied to samples from HIV positive men who have sex with men (MSM) who attended sentinel GUM sites across England, Wales and Northern Ireland, and who did not previously know their HIV status.

HIV Prevalence

Figure 1: HIV prevalence of previously undiagnosed HIV infection among attendees of sentinel GUM clinics across the UK, 2008

Data source: unlinked anonymous surveillance in 15 sentinel GUM clinics, Centre for Infections, Health Protection Agency: 2008
1 Previously undiagnosed HIV infection includes those diagnosed at the clinic visit as well as those who remained unaware of their infection, but excludes those that were diagnosed earlier.
2 Data for Scotland is represented by one clinic in Glasgow.

• Unlinked anonymous testing shows that of individuals attending sentinel sexual health clinics in 2008, 3.1% (291/9,473) of men who have sex with men (MSM) and 0.35% (322/92,694) of heterosexuals had a previously undiagnosed HIV infection.

• The prevalence was slightly higher amongst heterosexual women (0.40% [211/52,236]) than heterosexual men (0.32% [135/42,812]).
• Amongst heterosexuals, a higher prevalence was observed amongst those born in sub-Saharan Africa (2.1%, [118/5721]) than those born in the UK (0.18% [124/67751]) or elsewhere (0.42% [80/19222]).
• Similarly, the prevalence was higher in MSM born abroad (3.8% [126/3,357]) than those born in the UK (2.8% [148/5,386]).
• The prevalence was higher in individuals attending GUM clinics in London than outside apart from amongst sub-Saharan African born heterosexuals.

HIV Test Uptake and Outcome

Figure 2: The proportion of GUM attendees receiving an HIV test and the fraction of HIV positive individuals remaining undiagnosed on leaving the clinic, sentinal GUM clinics, UK 1999-2008

Data source: unlinked anonymous surveillance in 15 sentinel GUM clinics, Centre for Infections, Health Protection Agency: 2008

• Overall, the proportion of attendees receiving an HIV test increased more than three-fold between 1999 and 2008, from 29% (18,980/65,613) to 93% (97,444/104,370).

• Unlinked anonymous testing revealed that amongst individuals attending the sentinel GUM clinics with a previously undiagnosed HIV infection, the proportion receiving an HIV test has increased almost two-fold over the same period, from 42% (182/430) in 1999 to 77% (488/634) in 2008.
• The proportion of HIV positive individuals leaving the GUM clinic undiagnosed reduced by more than half over the same period, from 58% (248/430) to 23% (146/634). The pattern is similar for MSM and heterosexuals (Figure 2).
• Amongst heterosexuals, whilst there is no difference in overall HIV test uptake by world region of birth, a higher proportion of HIV positive SSA born heterosexuals leave the clinic undiagnosed (21% (23/111)) than UK born HIV positive heterosexuals (12% (15/122)) or HIV positive heterosexuals born elsewhere (13% [10/80]).
• Amongst MSM, there is little difference in HIV test uptake or the proportion remaining undiagnosed by world region of birth.

Recent HIV infection amongst men who have sex with men (MSM) attending GUM clinics

• A serological testing algorithm for recent HIV seroconversion (STARHS) was carried out on 200 sera from HIV positive MSM with a previously undiagnosed HIV infection. The mean time since seroconversion for sera testing positive for STARHS is six months.
• Of these 200, 47 (24%) were found to have a ‘recent’ infection and 153 (77%) had a ‘long-standing’ infection.
• 74% (35/125) of those with a ‘recent’ infection received an HIV test, compared to 59% (90/125) of those with a ‘long-standing’ infection.
• 32% (7/22) of infections amongst MSM under 25, 26% (24/93) of men aged 25-34 and 18% (15/82) of men aged 35+ had a ‘recent’ infection.
• 21% (24/113) of MSM in the UK and 26% (23/87) of MSM born outside the UK had a ‘recent’ infection.

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Last reviewed: 23 February 2010