Increase in HIV figures for UK gay men is due to more testing, not more new infections

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The increase in HIV diagnoses among men who have sex with men (MSM) in the United Kingdom since 1997 reflects an increase in HIV testing rather than a rise in the number of men infected each year, according to a study published in the online edition ofSexually Transmitted Infections this week. The research, conducted by Sarah Dougan and colleagues at the Health Protection Agency (HPA), looked at HIV diagnoses in the UK between 1997 and 2004. Throughout the UK, HIV diagnoses among MSM rose by 54% during this time but rates of new infection appear to have remained stable.

“It seems that the number of gay men becoming infected with HIV each year has remained steady. Instead, we are seeing more people who are already infected coming forward to test,” said Professor Jonathan Elford from City University London, a co-author on the study. “Among young gay men in London, the story is better still. Even though there was a substantial increase in the percentage of young men coming forward to test in London, we saw no increase in the number of new HIV diagnoses in this group”

This is the first time that changing patterns of HIV incidence and testing among MSM in the UK have been systematically investigated to explain the recent increase in HIV diagnoses. Estimates of HIV incidence were derived using data from UK HIV surveillance systems and data on HIV testing were provided by KC60 statutory returns, voluntary testing and unlinked anonymous surveys in so-called sentinel genitourinary medicine (GUM) clinics that contribute samples to monitor HIV prevalence and incidence to the HPA. While there was no evidence of a statistically significant increase there was also no evidence of a decrease in HIV incidence among MSM.


statistical significance

Statistical tests are used to judge whether the results of a study could be due to chance and would not be confirmed if the study was repeated. If result is probably not due to chance, the results are ‘statistically significant’. 

The data also show that, compared to the rest of the UK, London HIV awareness initiatives seem to have had a greater impact. Even with the substantial increase in HIV testing, there has been no increase in the number of gay men under 35 diagnosed with HIV each year in London between 1997 and 2004, compared with a 110% increase outside London (excluding Scotland). For gay men over the age of 35, London has seen a 55% increase in the number of HIV diagnoses compared to a 187% increase outside London. Scotland saw a 66% increase in the number of MSM diagnosed. Another piece of encouraging data showed that a higher proportion of gay men who go to GUM clinics for checkups are now testing for HIV, with 80% who are offered a test now accepting it.

The increased uptake of testing has been highest in London. Between 1997 and 2004, the number of both low and high risk gay men testing for HIV went up by 84% in London and 76% outside London. While London saw a greater increase in HIV tests, the number of new diagnosis in all age groups was much lower with only a 24% increase in positive HIV diagnoses compared with 146% outside London (excluding Scotland).

The study concludes that the substantial increase in the uptake of HIV testing in recent years highlights the recent success of sexual health promotion in reducing the number of gay men with undiagnosed HIV. A more proactive approach to offering the HIV test to gay men in GUM clinics only became standard policy towards the end of the period under analysis, so this change in policy cannot wholly explain the increased uptake of testing.

Sarah Dougan et al. Does the recent increase in HIV diagnoses among men who have sex with men in the United Kingdom reflect a rise in HIV incidence or increased uptake of HIV testing? STI Published Online First: 9 November 2006. doi:10.1136/sti.2006.021428