Community study finds no evidence of widespread HCV epidemic among HIV-negative gay men in London

Prevalence in HIV-negative men similar to the general population; HCV predominantly diagnosed in HIV-positive gay men
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Approximately 1% of HIV-negative gay men in London had antibodies to the hepatitis C virus (HCV) in 2008, results of a community survey published in HIV Medicine show. The study’s findings support those of clinic-based research which found no evidence of an HCV epidemic among HIV-negative gay men.

“Prevalence in HIV-negative MSM [men who have sex with men] was not significantly higher than in the general population,” comment the authors.

However, 8% of HIV-positive gay men had antibodies to HCV, further evidence of the ongoing epidemic of the infection in this population. Prevalence of HCV was higher among men reporting unprotected sex with a casual partner and in those with a history of syphilis.

Glossary

syphilis

A sexually transmitted infection caused by the bacterium Treponema pallidum. Transmission can occur by direct contact with a syphilis sore during vaginal, anal, or oral sex. Sores may be found around the penis, vagina, or anus, or in the rectum, on the lips, or in the mouth, but syphilis is often asymptomatic. It can spread from an infected mother to her unborn baby.

unprotected anal intercourse (UAI)

In relation to sex, a term previously used to describe sex without condoms. However, we now know that protection from HIV can be achieved by taking PrEP or the HIV-positive partner having an undetectable viral load, without condoms being required. The term has fallen out of favour due to its ambiguity.

blood-borne virus (BBV)

A virus transmitted through contact with infected blood. Hepatitis B, hepatitis C and HIV are BBVs. (Note that hepatitis B and HIV may also be transmitted through other body fluids).

 

 

person years

In a study “100 person years of follow-up” could mean that information was collected on 100 people for one year, or on 50 people for two years each, or on ten people over ten years. In practice, each person’s duration of follow-up is likely to be different.

sample

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

According to the recently published Public Health England report Hepatitis C in the UK, enhanced surveillance of new hepatitis C infections in men who have sex with men shows that incidence of hepatitis C in HIV-positive men has declined significantly since 2008, to 2.2 new infections per thousand person years of follow-up in 2012.

Since new diagnoses of HCV infection have been very heavily concentrated in HIV-positive gay men it is unlikely that prevalence among HIV-negative gay men has increased substantially since 2008.

The investigators believe their findings support “risk-based” HCV testing for HIV-negative gay men.

HCV is a blood-borne virus and most cases in the UK involve individuals with a history of injecting drug use.

However, since 2000 there has been an epidemic of sexually transmitted HCV among HIV-positive gay men.

Research conducted in London sexual health clinics has found little evidence that the epidemic involves HIV-negative gay men. One study found a prevalence of 0.4%, similar to the 0.2% prevalence seen in HIV-negative heterosexual men.

HIV-negative gay men are not considered to be at high risk of HCV. Therefore, British sexual health guidelines do not recommend that they should be routinely tested for HCV. Investigators from the Gay Men’s Sexual Health Survey (GMSHS) wanted to see if such an approach was justified.

The GMSHS involves gay men recruited in community settings such as gay bars, clubs and saunas. In 2008, 1121 men completed short questionnaires about their demographics and sexual risk behaviour and also provided samples of oral fluid which were tested for antibodies to HIV, HCV and syphilis.

The participants had a median age of 33 years (range, 16 to 81 years).

Antibodies to HIV were present in 15% of men and 12% had antibodies to syphilis. The overall prevalence of antibodies to HCV was 2.1%. But prevalence differed according to HIV infection status and was significantly higher in HIV-positive men compared to HIV-negative men (7.7 vs 1.2%; p < 0.001).

There was also a higher prevalence of antibodies to HCV among men who had antibodies to syphilis compared to men with no evidence of this infection (12.2 vs 1.7%; p < 0.001).

HCV antibodies were more common in men who reported having had a sexually transmitted infection in the past year, compared to men who had not had such an infection (4.7 vs 1.8%; p = 0.03).

Prevalence of HCV antibodies was also significantly higher among men who had reported unprotected anal intercourse (UAI) in the past year with a casual partner than in men who did not report this sexual behaviour (4.1 vs 1.2%; p = 0.01).

“In a community sample of MSM in London we did not find any evidence of a large number of HIV-negative MSM with evidence of exposure to HCV,” write the authors.

They acknowledge that a limitation of their study was that they did not enquire about injecting drug use. Some doctors now believe that a proportion of the HCV infections among HIV-positive gay men attributed to sexual transmission may in fact be a consequence of sharing injecting equipment.

The investigators believe the low prevalence of HCV antibodies in HIV-negative gay men “supports the practice at most GUM clinics where HCV testing…is not routine for HIV-negative MSM”. However, they suggest that testing should be considered for this population according to their risk profile. “Those with a history of UAI with casual partners and those with syphilis infection should be considered at higher risk.”

References

Price H et al. Hepatitis C in men who have sex with men in London – a community survey. HIV Medicine, doi: 10.1111/hiv.12050, 2013.