::: HCV News :::

We have spent the last 21 years fighting an emerging epidemic of HIV across the globe with a modicum of success, at least on the treatment front. Highly active antiretroviral therapy (HAART) has now allowed us some breathing room in which to develop better therapies and to address prevention issues that have been rather less successfully tackled in most countries. We have been slow to realize that hepatitis C virus (HCV) represents our next challenge; in fact, surveillance systems are not properly in place in most countries. In the United Kingdom there are an estimated 300,000 HCV cases, over 90% of which are as yet undiagnosed, in comparison to approximately 33,500 people living with HIV, about 30% of whom are undiagnosed. The significance of sexual transmission in the HCV epidemic has been a matter of controversy,^[1] although there is some evidence that it may be an important method of acquisition, at least among men who have sex with men (MSM).^[2]

In a study from a large UK hospital, Browne and colleagues^[3] presented circumstantial evidence that sexual transmission is responsible for an increasing incidence of HCV in HIV-infected individuals. Cases of HCV were identified among individuals with a previously negative HCV antibody result who attended sexual health services between 1997 and 2002. The number of these HCV seroconverters increased from zero during 1997 to 10 during the first half of 2002. A total of 23 cases were seen, of whom only 1 was female, and 21 of these were known to be HIV-infected, including 2 who seroconverted to both viruses concurrently. Although 4 subjects gave a classic history of injection-drug use and needle sharing, 19 did not; these were all MSM, 15 of whom reported recent unsafe sex. Eight subjects in this cohort developed syphilis temporarily associated with HCV seroconversion.

Further details were presented on the 21 subjects known to be coinfected with HIV and HCV. All of the HIV-infected individuals diagnosed with HCV were identified by screening for HCV RNA among those with abnormal liver function, using stored blood samples to try to identify the date of acquisition. Routine antibody tests were also performed which were initially negative, and the median time from detection of HCV RNA to HCV antibody positivity was 4 months (range, 3.0-9.5 months). The rate of diagnosis of HCV among HIV-infected subjects found to have elevated liver function tests increased during the study period from 10.7% to 40%, a statistically significant change (P = .035, Chi-squared test). Among this population of HIV-infected patients with elevated liver function tests, the rate of diagnosis of HCV in 2002 was 5.1 cases per 1000 patient-years (95% confidence interval [CI], 2.2-10.1), which appeared to be significantly higher than the rate in 1997 (0 cases per 1000 patient-years; 95% CI, 0-1.2). This would suggest that the HCV infection burden within the HIV-infected population increased during the study period.

This study raises a concern that the use of HCV antibody tests alone may not be sufficient to identify individuals who acquire HCV with only sexual risk factors or even in low incidence areas, potentially delaying the diagnosis of active infection and thus increasing the risk of onward transmission. The use of stored blood to retrospectively identify HCV seroconversion allows for an accurate identification of time of infection in epidemiologic studies, and further work addressing sexual acquisition is required to identify more clearly the risk factors for transmission as well as the outcomes of these infections. From a public health perspective, more aggressive surveillance studies should be performed, and health promotion messages need to be developed to educate those at risk.

References

1. Bernard EJ. Sexual transmission of hep C. In: AIDS Treatment Update.
   
   London: NAM Publications. September 2002; Issue 117. Available at: http://www.aidsmap.com/publications/atu/atu117.pdf Accessed December 16, 2002.
2. Craib KJP, Sherlock CH, Hogg RS, O'Shaughnessy MV, Schechter MT. Evidence of sexual transmission of hepatitis c virus (HCV) in a cohort of homosexual men. Program and abstracts of the 8th Conference on Retroviruses and Opportunistic Infections; February 4-8, 2001; Chicago, Illinois. Abstract 561.
3. Browne R, Asboe D, Gilleece Y, et al. Increased incidence of HIV-positive individuals with acute hepatitis C due to sexual transmission: a new epidemic? Program and abstracts of the Sixth International Congress on Drug Therapy in HIV Infection; November 17-21, 2002; Glasgow, Scotland. Abstract P283.