Against a background of fewer diagnoses among heterosexuals infected abroad, the number of gay men diagnosed with HIV in the UK continues to rise, the Health Protection Agency announced today. Moreover, one quarter of them had recently acquired their infection, suggesting a high level of risk taking in this group.
The annual epidemiological report also shows that while one in two HIV diagnoses is made late (with a CD4 cell count below 350 cells/mm3), rates of late diagnosis have been slowly falling over the past decade.
More encouragingly, the proportions of people with diagnosed HIV who are linked to care and on successful treatment are exceptionally high.
New diagnoses and infections
Whereas there have been falls in the total number of new diagnoses in recent years, 2010’s figure is very similar to that recorded in 2009. A total of 6658 people were diagnosed with HIV.
Half the new diagnoses were in people who acquired HIV through heterosexual sex (around 3350 people). Two thirds of this group are thought to have acquired HIV abroad, and the numbers infected overseas have been falling for several years now. One third of heterosexual infections probably occurred in the UK – this figure has slowly increased over the past decade.
Forty five per cent of the new diagnoses were in gay and bisexual men. With around 3000 men diagnosed in one year, this is the largest annual figure ever recorded. It has gone up from 1820 in 2001, 2660 in 2005 and 2790 in 2009.
Four fifths of newly diagnosed gay men probably acquired HIV in the UK. While the majority of newly diagnosed men are of white ethnicity (83%), one third were born outside the UK.
The HPA also present data from new systems for detecting how recently a person acquired HIV. The procedure, known as RITA (Recent Infection Testing Algorithm) identifies newly diagnosed individuals who were probably infected in the past four or five months. The test is being currently rolled out. 37% of the new diagnoses reported in 2010 could be analysed by RITA.
Gay men are far more likely to be diagnosed during recent infection than other people. Whereas 7% of heterosexual women and 9% of heterosexual men have recent infection, 24% of newly diagnosed gay men have recent infection.
People who are diagnosed when they are younger are more likely to have recent infection than older people. Among gay men diagnosed under the age of 35, rates of recent infection are high at 31%, whereas in gay men diagnosed over the age of 50, the figure is 13%.
Higher rates of recent infection were also observed in heterosexual women aged 15-24 (14%) and heterosexual men aged 25-34 (14%).
When there are large numbers of people with recent infection, this suggests that HIV transmission is occurring frequently . High rates could also be due to regular HIV testing. The variation by age group may also be due to the fact that younger people have less time to have infections than older people.
The HPA estimates that, at the end of 2010, there were 91,500 people living with HIV in the UK. However one quarter of them are unaware of their infection. Moreover, the epidemiologists anticipate that by the end of 2012, there will be more than 100,000 people living with HIV in the UK.
The HPA now estimate that 1 in 20 gay men in the UK are infected with HIV. In London, where the infection is more common, 1 in 12 are infected. (These figures are based on the assumption that 3.4% of adult men are gay or bisexual). Among black African men and women living in the UK, an estimated 1 in 20 are infected with HIV.
Testing and late diagnosis
In 2010, 50% of all new diagnoses were made late – in other words, when the CD4 cell count was below 350 cells/mm3, by which stage treatment is recommended.
The proportion diagnosed late is higher in heterosexual men (63%) and heterosexual women (58%) than it is among gay and bisexual men (39%). Black African and black Caribbean people are more likely to be diagnosed late than white people. People diagnosed over the age of 50 are more likely to be diagnosed late than younger people.
But over the past decade, there has been a steady decline in the proportion diagnosed late, from 59% in 2001 to 50% in 2010 (p <0.0001 for trend).
So while progress is being made, it is being made very slowly. The HPA says that the proportion of late diagnoses is still “very high”.
“We want to see increased access to HIV testing routinely offered in clinical settings such as new registrants at GPs and hospital general admissions, in areas of the country where rates of HIV infection are high,” said Dr Valerie Delpech of the HPA.
Moreover, the HPA recommends that late HIV diagnosis be included within the Public Health Outcomes Framework (a set of indicators to evaluate how well the health system is performing) and that local authorities should use this indicator.
Whereas the HPA has been recommending for a number of years that men who have sex with men should take an HIV test at least once a year, it now gives the same advice to black African people and those who inject drugs. Moreover, it says that gay men who have unprotected anal intercourse with casual partners or new partners should test more often.
Underlining the importance of prompt diagnosis, the report notes that among the 680 people with HIV who died in 2010, two thirds were people who had been diagnosed late. On the other hand, a recent study suggests that the outlook for people who are diagnosed promptly is excellent, with life expectancy just a few years shorter than that of people without HIV.
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