Epidemiology

Time to seroconversion after acute HCV infection variable in injection drug users

Last Updated: 2005-03-29 9:44:12 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Data from a long-term prospective investigation of acute-phase hepatitis C virus infection among injection drug users show that seroconversion may occur 2 months after detection of viremia. The findings "underscore the importance" of nucleic acid screening of blood donations to prevent HCV transmission, researchers say.

The data also reaffirm the need to follow HCV-positive injection drug users long-term to check for viral persistence.

Among 179 HCV antibody-negative injection drug users followed in the study, an "alarming" 34% seroconverted despite risk reduction counseling, Dr. Andrea L. Cox, from the Johns Hopkins Medical Institutions in Baltimore, Maryland, and colleagues report in the April 1st issue of Clinical Infectious Diseases.

As expected, acute-phase HCV infection was largely asymptomatic. "Viremia was the earliest marker of acute-phase HCV infection, preceding detection of HCV-specific antibodies by 5-6 weeks, and in 1 case, by > 12 months," they report. However, in all other cases HCV RNA was detected no more than 63 days before seroconversion.

Alanine transaminase, while uniformly elevated during acute-phase HCV infection, did not correlate closely with HCV RNA levels or viral persistence. Bilirubin levels were also elevated during acute-phase HCV infection but no patient had jaundice.

In cases of viral persistence, a stable serum level of HCV RNA was noted in some individuals within 2 months after the first detection of viremia, while in others, it was not apparent until more than 1 year later.

In cases of viral clearance, on the other hand, HCV became persistently undetectable as early as 94 days and as late as 620 days after initial viremia.

In an editorial, Drs. Michael P. Busch and Kimberly A. Page Shafer from the University of California in San Francisco say these data show that clearance of acute-phase viremia can occur "much later than has been observed in transfusion recipients."

For now, routine HCV RNA or HCV antigen screening outside of the context of donor screening and research protocols is "probably premature" for many reasons, including "the controversy over the merits of early treatment," they add.

They remind clinicians that the most recent guidelines from the American Association for the Study of Liver Diseases with respect to acute-phase HCV infection state that "no definitive recommends can be made regarding early detection and treatment."

Clin Infect Dis 2005;40:951-958.