HIV and hepatitis C virus (HCV) transmission networks are closely linked, according to Swiss research published in the International Journal of Epidemiology. Combining clinical data with phylogenetic analysis of HIV samples from a drug resistance database showed that the risk of incident HCV infection was increased by a factor of two if a patient was “clustered” with another patient with HCV.
“Our results indicate that the transmission networks of HIV and HCV are correlated and overlap even beyond the degree that can be expected by demographic variables such as risk group…geography, sex and age,” comment the authors. “Thus, our analysis shows that the location of an HIV-infected patient on the HIV phylogeny can serve as an indicator for the risk of an HCV coinfection.” They believe their findings have important implications for HCV prevention efforts, allowing the identification of people with an especially high risk of infection.
HIV and HCV can both be acquired by contact with blood. There is also an ongoing epidemic of sexually transmitted HCV among HIV-positive gay men. A significant proportion of people living with HIV therefore have hepatitis C co-infection, and liver disease is an important cause of serious illness and death in this group.
However, the extent to which HIV and HCV transmission networks overlap is uncertain. A clearer understanding of this issue could assist in the development of targeted HCV prevention campaigns.
Investigators therefore obtained information on HCV infection status for people enrolled in the Swiss HIV Cohort Study (SHCS). This was combined with information on HIV and HCV risk group – injecting drug use (IDU), heterosexual, men who have sex with men (MSM), heterosexual/IDU, or MSM/IDU.