Prevalence of antibody to hepatitis C virus in prospectively followed acute non-A, non-B hepatitis, from different epidemiological categories.

We have studied the prevalence of antibody against hepatitis C virus (anti-HCV) and its relation to the time of onset of the symptoms in 57 patients with acute non-A, non-B hepatitis: 16 post-transfusion, 25 drug addicts and 16 sporadic cases. In the 1st month after the onset of illness, anti-HCV was positive in 25% of patients with post-transfusion hepatitis, 44% of drug addicts and 25% of sporadic hepatitis. In the 3rd month this antibody was detected in 75%, 88% and 31.2%, and in the 6th month in 87.5%, 96% and 31.2%, respectively. The prevalence in the 3rd and 6th months was significantly higher in post-transfusion patients and drug addicts than in sporadic cases. In the 6th month the prevalence of anti-HCV in patients who progressed towards chronicity was also significantly higher than in those with acute resolving non-A, non-B hepatitis (94% vs 50%, p less than 0.001). These results show that HCV is probably the main agent in acute post-transfusion non-A, non-B hepatitis and in those occurring in drug addicts, and that in a high proportion of these patients the anti-HCV can be detected in the 3rd month after the beginning of the symptoms. On the other hand, the relation of hepatitis C virus with sporadic acute non-A, non-B hepatitis may be doubtful.