Cox AL et al. (2005) Prospective evaluation of community-acquired acute-phase hepatitis C virus infection. Clin Infect Dis 40: 951–958

A recent study published in Clinical Infectious Diseases draws attention to the high incidence of HCV infection among injection drug users, and indicates that liver-function testing alone cannot reliably exclude a positive diagnosis.

Cox and co-workers prospectively evaluated 179 HCV antibody-negative injection drug users aged 15–30 years, of whom 62 (35%) seroconverted during follow-up. This corresponded to an overall incidence of 27.2 HCV seroconversions per 100 person years. The majority of those with sufficient follow-up remained viremic, although one-fifth cleared viremia.

Twenty individuals who seroconverted were included in a more detailed analysis of the characteristics of acute-phase HCV infection. The results showed that viremia was the earliest marker of infection, preceding detection of HCV-specific antibodies by a mean of 36 days. HCV RNA could be detected in serum samples before the elevation of alanine aminotransferase and total bilirubin levels in 45% and 77% of cases, respectively, and none of the patients developed jaundice or other symptoms that prompted them to seek medical attention. In those who cleared viremia, long-term clearance was evident 94–620 days after the initial viremia was detected.

Cox et al. note that the incidence of HCV infection found here was alarming, especially given the efforts to reduce high-risk behavior among study participants. They emphasize the need to carry out nucleic acid screening on donated blood and to carry out long-term follow-up of those infected with HCV.