One in three HIV-positive gay men in London unaware they are infected

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A third of HIV-positive gay men in London are unaware that they have the infection, according to a study published in the June 2nd edition of Sexually Transmitted Infections. The study also found that the proportion of gay men reporting unprotected anal sex has been rising steadily since 1996.

These worrying findings are based on the results of annual questionnaires completed by over 1200 gay men recruited in bars, clubs and saunas across London between 1996 and 2000. The surveys covered demographic details, sexual health service use, HIV testing history, HIV status and sexual behaviour.

In 2000, the men were also asked to provide saliva samples, which were tested for antibodies to HIV and anonymously linked to survey responses.

Glossary

risky behaviour

In HIV, refers to any behaviour or action that increases an individual’s probability of acquiring or transmitting HIV, such as having unprotected sex, having multiple partners or sharing drug injection equipment.

odds ratio (OR)

Comparing one group with another, expresses differences in the odds of something happening. An odds ratio above 1 means something is more likely to happen in the group of interest; an odds ratio below 1 means it is less likely to happen. Similar to ‘relative risk’. 

sample

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

antiretroviral resistance

A drug-resistant HIV strain is one which is less susceptible to the effects of one or more anti-HIV drugs because of an accumulation of HIV mutations in its genotype. Resistance can be the result of a poor adherence to treatment or of transmission of an already resistant virus.

adjusted odds ratio (AOR)

Comparing one group with another, expresses differences in the odds of something happening. An odds ratio above 1 means something is more likely to happen in the group of interest; an odds ratio below 1 means it is less likely to happen. Similar to ‘relative risk’. 

One thousand two hundred and six saliva samples were collected, 132 (11%) of which were found to be positive for HIV antibodies. Of these, 43 (33%) were from men who had not been diagnosed as HIV-positive.

Of the 996 (83%) men who said they knew their HIV status, 41 (4%) were mistaken.

The HIV-positive men were more than twice as likely to have had a sexually transmitted infection in the past year as the HIV-negative men (adjusted odds ratio [OR] = 2.13; 95% CI, 1.40 – 3.24). They were also more likely to have had unprotected sex with more than one partner, and to have had more than one casual partner (adjusted OR = 2.21; 95% CI, 1.46 – 3.33). The HIV-positive men were more likely to be above 35 years of age, to have had fewer than three years of education after the age of 16 and to be unemployed (OR = 2.26; 95% CI = 1.46 – 3.51).

Across HIV-positive and HIV-negative groups, the proportion of men reporting unprotected anal sex increased significantly each year, from 30% in 1996 to 42% in 2000 (p

Around one half of the diagnosed and undiagnosed HIV-positive men reported having had unprotected anal sex in the last year. The authors comment, “Despite emphasis on risk reduction counselling in clinics, men who were diagnosed were as likely to engage in high risk sexual behaviour as undiagnosed men.”

“The high level of risky behaviour in HIV-positive men, regardless of whether they are diagnosed, is of public health concern,” conclude the authors, “in an era when HIV prevalence, antiretroviral resistance, and sexually transmitted infection incidence are increasing.”

Further information on this website

Record number of new UK HIV diagnoses made in 2003 - news story

Both older and younger gay men having more unprotected sex in San Francisco - news story

Barebacking: not a simple phenomenon, US research shows - news story

Evidence unclear as to whether gay men are having more risky sex - news story

Reference

Dodds J P et al. Increasing risk behaviour and high levels of undiagnosed HIV infection in a community sample of homosexual men. Sex Transm Infect 80:236-240, 2004.