To prospectively determine the prevalence of total hepatitis virus A antibodies in patients with chronic hepatitis C and to evaluate the direct costs of several vaccination strategies against hepatitis A virus in these patients.

From April 1 to July the 31 1998, 219 patients with hepatitis C virus antibodies underwent a systematic testing for total hepatitis virus A antibodies (MEIA-AXSYM, Abbott laboratories). The prevalence of hepatitis A virus antibodies was evaluated according to age and suspected way of hepatitis C contamination. This prevalence has been compared to that in individuals undergoing a check-up provided by the national health insurance system stratified by age. Direct costs of 2 vaccination strategies “A” and “B” were evaluated according to age (< 40 vs > 40 years) and number of vaccine doses (1 or 2). “A” strategy included the systematic vaccination of all patients without determining the presence of total hepatitis A antibodies. “B” strategy included testing for total hepatitis A antibodies and vaccination of seronegative patients. The costs of these two strategies (A and B) were calculated with one and two vaccine doses.

The prevalence of total hepatitis A antibodies was 76% in the entire population. It increased after the age of 35 and was statistically higher in patients who were older than 40 than in patients younger than 40. This prevalence was not significantly different from that in individuals who underwent a check-up provided by the national health insurance system stratified according to age. “B” strategy with 2 vaccine doses was less expensive that A strategy in the whole population and in patients younger than 40. This strategy was less expensive with 1 vaccine dose except in patients who had recently screened positive for hepatitis C antibodies younger than 40 when it induced an increased in direct cost due to the low prevalence of total hepatitis A antibodies in these patients.

In patients with hepatitis C antibodies with a high prevalence of total hepatitis A antibodies, testing for the prevalence of these antibodies before vaccination decreases the direct cost of this vaccination.