Changes in HIV prevalence among young Thai men as defined by hepatitis C co-infection as a marker for mode of transmission.

To obtain a better understanding of the evolving HIV-1 epidemic in Thailand, we utilized antibody to hepatitis C virus (HCV) to indicate the mode of HIV-1 transmission. Although the proportion of men with HCV co-infection increased between 1995 and 2000, the prevalence was similar, whereas the prevalence of men not co-infected decreased (1.93-0.46%). This suggests that HIV-1 infection associated with parenteral transmission has been stable despite a dramatic reduction in the sexual transmission of HIV-1.