HIV and chronic HCV co-infection prevalence in England highest among MSM

Men who have sex with men (MSM) make up the majority of people with chronic hepatitis C virus (HCV) who have co-infection with HIV, according to data from Public Health England (PHE) published in HIV Medicine. Approximately two-thirds of prevalent HIV infections among people with chronic HCV involved MSM, and the majority of these people were diagnosed with HIV at least six months before their HCV infection was detected.

“Tackling the risk of HCV and other sexually transmitted infections remains a challenge for HIV and sexual health services,” comment the authors. “Our findings support the British HIV Association guidelines, which indicate that persons with HIV infection should be tested regularly for HCV, with the majority of persons in our study diagnosed with HCV a number of months after their HIV diagnosis.”

In the UK, an estimated 214,000 individuals have chronic HCV while 101,000 people are living with HIV. Prevalence of HCV is highest among injecting drug users (IDU) and the highest prevalence of HIV infections is among MSM. Recently, epidemics of HCV have been detected among MSM in a number of settings, with most of the infections involving men who are already infected with HIV.

Investigators from PHE wanted to establish the prevalence of HIV among adults with chronic HCV infection. They therefore examined surveillance data collected between 2008 and 2014.

During the study years a total of 35,682 people tested positive for antibodies to HCV; 4% of these individuals also had HIV. Most of these people with co-infection were male (84%), two-thirds were of white ethnicity and 67% were diagnosed at a sexual health clinic. Prevalence of co-infection was higher among men than women (6% vs 2%).

PCR testing was conducted on 81% of people with HCV antibodies, the results showing that 70% (20,000) had chronic HCV infection. Five per cent of these people had been diagnosed with HIV prior to or within six months of HCV being detected. The people with co-infection were overwhelmingly male (88%), of white ethnicity (71%) and were diagnosed via sexual health services (67%).

The highest prevalence of co-infection was among men (6%) and individuals aged 30 to 54 years (5%).

Information on HCV risk was available for 81% of people with co-infection. The most frequent route of transmission was sex between men (65%; 3% also reported IDU), followed by IDU (22%) and heterosexual contact (12%).

Two-thirds of individuals with co-infection were diagnosed with HIV six or more months before their HCV infection was detected. A further 12% had their HIV and HCV infections diagnosed on the same day.

Of the people with long-standing HIV infection before their positive HCV result, 41% had a previous negative HCV test in the interval between the diagnosis of HIV and HCV.

“Most people meeting our criteria for diagnosed co-infection had been diagnosed with HIV infection > 6 months before their HCV diagnosis,” comment the investigators. “A large proportion of these had also previously tested negative for anti-HCV between 2008 and 2014, suggesting that persons with HIV infection continue to engage in behaviour after their diagnosis that puts them at increased risk of HCV infection.”

Factors associated with co-infection included male sex and black ethnicity, while older age and Asian ethnicity were associated with a lower risk of co-infection.

Only 37 people (0.19%) were diagnosed with HIV after their diagnosis with HCV. Three-quarters of these people were men. As regards HCV risk group, 50% were IDU, 35% MSM (of whom 3% also reported IDU) and 15% were heterosexuals.

“Diagnosed co-infection is mainly associated with high-risk sexual behaviour, rather than injecting drug use, the dominant risk factor for those who are HCV mono-infected,” conclude the authors. “More needs to be done to increase awareness of HCV infection risk and the need for regular testing and to encourage safer sex, as well as to understand the contribution of ‘chemsex’ to HCV and HIV infection risk.”