HIV incidence is falling in English gay men, say Public Health England

While several recent reports have shown that new HIV diagnoses have been falling in UK gay men, what really matters is the actual number of new HIV infections, regardless of whether people are diagnosed or not. This is HIV incidence and Public Health England (PHE) said today that, according to their current estimates, incidence among gay and bisexual men in England has been falling since 2012. In previous years, PHE has always believed that incidence was stable.

As HIV incidence includes new infections that have not yet been diagnosed, it is inherently difficult to estimate. The method PHE uses is based on the CD4 counts of men diagnosed with HIV – for example, a man diagnosed with HIV at a CD4 count of 400 is likely to have acquired HIV about four years ago. So new diagnosis data collected this year helps refine the estimates of incidence in previous years.  

According to the new estimates, infections in gay and bisexual men have been steadily falling for five years: 2800 infections in 2012, 2100 infections in 2014 and 1700 infections in 2016.

The figures appear in PHE’s annual surveillance report, issued today. While most of the key findings have already been reported by aidsmap in the last few months (here, here, here and here), some interesting extra details are provided. And there is a great deal of new data on HIV testing, covered in another article.

How many people have undiagnosed HIV?

The estimated figures for people with undiagnosed HIV have been falling, bringing England close to meeting the United Nations 90-90-90 targets. It is estimated that 88% of people living with HIV have been diagnosed, 96% of those diagnosed are taking treatment and 97% of those treated have an undetectable viral load.

An estimated 10,400 people living with HIV have not been diagnosed.

• 13% of gay men living with HIV remain undiagnosed (6100 men).
• 25% of people who inject drugs living with HIV remain undiagnosed (500 people).
• 14% of heterosexual men living with HIV remain undiagnosed (1100 men of African ethnicity and 1300 men of other ethnicities).
• 6% of heterosexual women living with HIV remain undiagnosed (600 women of African ethnicity and 700 women of other ethnicities).

Given the limited data used to calculate these figures, it’s worth remembering that these are all estimates. PHE is more uncertain of its figures for heterosexual men and for people who inject drugs than it is for women and for gay men.

The proportion of gay men who are undiagnosed is lower in London (10%) than it is elsewhere in England (16%).

Three-quarters of heterosexual men who are unaware of their HIV infection are over the age of 35. This is much higher than among undiagnosed women and gay men.

Are diagnoses falling as fast amongst all groups of gay men?

Between 2015 and 2016, new diagnoses in gay men decreased by 21%, from 3570 to 2810. But there are some inconsistencies between different parts of the gay population.

• Clinic location: while there was a 35% drop in new diagnoses at five central London sexual health clinics, the decrease was lesser elsewhere in London (down by 18%) and elsewhere in England (down by 16%). Without reporting detailed figures, PHE says that clinics in Manchester, Brighton and other cities with large gay populations have also seen above-average decreases.
• Age: younger men are benefiting the most. In London, the steepest decline in HIV diagnoses was seen among men aged 15-24 years (down 57%), followed by 25-34 year olds (down 33%) and 35-49 year olds (down 17%).
• Ethnicity: in London, there was a 37% decline in diagnoses in white gay men, comparable to that seen in black gay men (34%), but greater than that seen in Asian men (down 23%) and in men of other or mixed ethnicity (down 26%).
• Country of birth: in London, the greatest drops were in men born in the UK or in other parts of Europe, with smaller decreases in men born in Latin America, the Caribbean, Asia and Africa.

Where diagnoses are falling, this appears to be due to combination prevention – including condom use, expanded HIV testing, prompt HIV treatment and pre-exposure prophylaxis (PrEP). However, as well as the inequalities within the gay population, combination prevention has not been provided in the same way to heterosexual communities.

“The recent encouraging changes are dependent upon sustained prevention efforts,” comment Public Health England. “The inconsistencies between groups and geographies demonstrate that combination prevention needs to be replicated for all those at risk of acquiring of HIV, whoever they are and wherever they live.”

The health policy organisation The King’s Fund commented that the reduction in new HIV diagnoses is no reason to diminish the HIV response. “This data must be seen as an indicator of the reductions that are possible, rather than meaning that the job is done or that a downwards trajectory in new diagnoses will continue in the future,” they said.

References

Public Health England. Towards elimination of HIV transmission, AIDS and HIV-related deaths in the UK – 2017 report.