Small fall in new HIV diagnoses in London, but rate of new diagnoses among gay men continues to increase

There was a modest fall in the number of new HIV diagnoses in London in 2011, new figures show. A total of 2637 new diagnoses were made in the UK capital in 2011, a 4% fall compared to 2010.

However, this decline was attributed to changing patterns of migration with a fall in the number of new diagnoses involving black Africans. The number of new diagnoses among gay and other men who have sex with men (MSM) actually increased between 2010 and 2011, and there was also a modest increase in the number of diagnoses due to heterosexual transmission that occurred in the UK.

“HIV continues to be a major public health issue for London,” Public Health England (PHE) states in its new report on HIV epidemiology in London. The number of new diagnoses in London in 2011 was 11% higher than in 2000. Almost 50% of all UK diagnoses in 2011 were made in London, and about half of all HIV-positive people receiving HIV care in the UK are in the capital.

The new figures showed the seriousness of the ongoing HIV epidemic in MSM. A total of 1427 new diagnoses (54%) occurred in this group, a slight increase on the year before, and maintaining a long-term upward trend with the number of new diagnoses involving MSM 20% higher than in 2002. 

The PHE data showed the international character of the HIV epidemic among MSM. Only 45% of new diagnoses involved UK-born MSM; a fifth involved men born in another western European country and 12% were in men born in Latin America.

Overall, 43% of diagnoses in 2011 involved heterosexual men and women, a modest fall compared to 2010. Almost a third (30%) of new HIV cases in 2011 were in heterosexual men and women infected in Africa, a fall compared to 2010.

A total of 317 heterosexual cases were probably as a result of transmission in UK. The PHE figures showed that the number of new diagnoses involving UK heterosexual transmission has doubled since 2002.

Approximately 5% of new infections were in black Caribbeans, a proportion largely unchanged compared to 2010.

Only 39 new diagnoses involved injecting drug users.

MSM newly diagnosed with HIV tended to live in central and inner London boroughs, whereas newly diagnosed heterosexuals were dispersed across the capital.

Rates of new AIDS diagnoses and HIV-related deaths were low (159 and 169 respectively), further evidence of the success of antiretroviral therapy and the excellent prognosis of people receiving HIV care in the UK.

This low mortality rate, coupled with the high number of new diagnoses, means that more people than ever were receiving HIV care in the capital. The total number for 2011 was 31,000, an increase of 5% compared the year before. Eighteen of the 20 UK boroughs with the highest prevalence of diagnosed HIV infection are in London.

The PHE data showed that up to a fifth of all HIV infections in London are undiagnosed. Late diagnosis was also common. In 2011, 44% of London patients were diagnosed when their CD4 cell count was below 350 cells/mm³, the current threshold for starting antiretroviral therapy. Moreover, a quarter of newly diagnosed people were diagnosed very late, with a CD4 cell count that was below 200 cells/mm³, indicating a high risk of serious HIV-related illness.

These high rates of undiagnosed infection and late diagnoses are also of public health significance. The report highlighted data showing that an estimated 50% of all new HIV transmissions originate in individuals whose HIV has not been diagnosed.

“Taking measures to improve diagnosis of HIV through normalising and expanding HIV testing is key to reducing late and undiagnosed HIV,” says the report. However, figures show that only one in three primary care trusts in high-prevalence boroughs commissioned routine HIV screening in primary care, and only 20% commissioned new tests for medical admissions.

“Testing should be promoted among…higher risk groups to ensure individuals are aware of their HIV status,” PHE recommends.

Specifically, MSM are advised to have an HIV/sexually transmitted infections screen at least annually, or every three months if they are having unprotected sex with new or casual partners. Black African and Caribbean people are recommended to have an HIV test and a regular screening for HIV and other sexually transmitted infections if they are having unprotected sex with new or casual partners.

“To reduce late diagnoses and undiagnosed infections, expanded HIV testing should be commissioned in acute clinical admission units and primary care in areas of high prevalence,” suggests PHE.