Largest ever number of HIV diagnoses in UK gay men – due to increased testing and new infections

Roger Pebody
Published: 21 November 2013

During 2012, 3250 gay men were diagnosed with HIV in the United Kingdom, the largest number of cases ever recorded in this group. While there are several indications that more gay men are getting tested (and so some of the diagnoses are of previously acquired infections), the figures are also fuelled by risky behaviour and new infections. Epidemiologists at Public Health England estimate that around 2400 men who have sex with men (MSM) newly acquired HIV during the year – a figure that has not changed in the past decade.

Whereas the annual number of diagnoses in gay men and other men who have sex with men has hovered between 2800 and 3000 cases in recent years, 3250 men were diagnosed in 2012, accounting for half of all new diagnoses. The median age at diagnosis was 34, although one in nine was over 50 years old.

Several pieces of data suggest that efforts to increase the number of gay men who test, and the frequency with which they do so, are beginning to pay off:

  • The proportion of gay men living with HIV who were unaware of their infection fell from 26% in 2010 to 18% in 2012. The estimated number of gay men with undiagnosed infection was 10,300 men in 2010 and 7300 men in 2012.
  • The proportion of new diagnoses that were made late (with a CD4 cell count below 350 cells/mm3) dropped from 38% in 2010 to 34% in 2012, although the absolute number has not gone down.
  • The number of gay male attendees of sexual health clinics taking an HIV test increased by 13% in one year, from 64,270 in 2011 to 72,710 in 2012. (Unfortunately, equivalent figures are not available for testing in other settings.)

Improved HIV testing practices have therefore likely contributed to the greater number of HIV infections which are diagnosed. But Public Health England also believe that HIV transmission continues at high levels – their estimations of HIV incidence using a back-calculation analysis suggest that there have been 2300 to 2500 new infections in gay men each year over the past decade. The large majority of transmissions originate in men unaware of their own infection.

Data from the Recent Infection Testing Algorithm (RITA) point to ongoing HIV transmissions. One-in-five newly diagnosed gay men are thought to have acquired their infection in the previous six months, with the proportion highest in younger men and in Londoners.

In several other places, the new epidemiological report points to the particular role that London plays in the UK’s epidemic, especially among gay men – far more gay male diagnoses were made in the city (1450) than in other regions, with the upward trend in diagnoses most marked there. The number of tests in sexual health clinics also rose faster in London than in the rest of the country.

Moreover, half of the UK’s local authorities which have a high prevalence of HIV (across all population groups) are located in London. Havering, on the eastern outskirts of the city, is the only London borough with an HIV prevalence below 2 per 1000 people aged 15-59 years.

Nonetheless, there is an uneven geographical spread of HIV within London, with particular concentrations in areas with more socioeconomic problems. In the most deprived areas (defined with reference to a range of economic, social and housing indicators), 7 in 1000 people had diagnosed HIV. In the least deprived areas, 2.4 in 1000 had HIV.

New diagnoses among heterosexual men and women

In 2012, 2880 new HIV diagnoses were in heterosexual men and women, continuing the downward trend seen in recent years (there were as many as 4900 annual diagnoses a decade ago). Around six in ten were women, and on average women were diagnosed at a younger age (37 years) than men (42 years).

Around half the heterosexual infections were in people of black African ethnicity.

Updated methods to estimate whether an infection was acquired in the UK or abroad (based on the CD4 cell count and date of arrival in the UK, if applicable), suggest that half (52%, based on 2011 figures) of all newly diagnosed heterosexual infections were probably acquired in the UK – this proportion has increased from a quarter in 2002.

Among heterosexual people who were born abroad, almost half (48%) probably acquired their HIV in the UK, highlighting the need for prevention work with this group. As a rough estimate, around 1000 black African men and women acquire HIV in the United Kingdom each year.

The proportions of heterosexual people living with HIV whose infection is undiagnosed (30% of men and 24% of women) and who were diagnosed late (65% of men and 57% of women) have not had such noticeable declines as has been seen in gay men.

Quality of HIV care

In terms of the HIV treatment cascade, the UK has a considerable problem in relation to undiagnosed HIV (only 78% of people with HIV are diagnosed), with inequalities between different parts of the population.

However, the report points to good results at other steps of the treatment cascade – 97% were linked to care after diagnosis (defined as a CD4 cell count within three months), 95% were retained in care (received HIV care both in 2011 and 2012), and 89% of people with a CD4 cell count below 350 cells/mm3 took antiretroviral treatment.

Moreover, there was equality in these results. There were very similar figures for linkage to care, retention in care and access to treatment in people of different ages, ethnicities, genders, exposure groups and geographical regions. The only exception is that younger people were less likely to take treatment than older people.

Overall, two thirds of people living with HIV in the UK (including undiagnosed people) were taking treatment and just under half had an undetectable viral load.

Public Health England therefore argues that changing guidelines so that antiretroviral treatment is taken at higher CD4 cell counts would have a limited impact on onward transmission – reducing the number of people with undiagnosed infection would have more impact.

For that reason, the agency is supporting National HIV Testing Week, which begins tomorrow: “It is a great opportunity to alert people to the benefits of testing – for individuals and for the UK’s public health,” commented Professor Kevin Fenton of Public Health England. “PHE is urging members of the public, clinicians, commissioners and community leaders to support and engage with the campaign.”

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