Serological survey on hepatitis E virus infection in an endemic area: diagnosis potential of enzyme immunoassay for detection of IgG antibody.

BACKGROUND: Hepatitis E is a major cause of acute icteric disease widespread in tropical and sub-tropical regions but rarely occurring in industrialized countries. Recently solid-phase enzyme immunoassays with recombinant antigens have been introduced for diagnosis of this infection. OBJECTIVES: The aim of this study was to evaluate the diagnostic potential of a newly developed Abbott test for the detection of IgG class antibodies to hepatitis E virus (anti-HEV IgG) in hepatitis patients and 'normal' individuals. STUDY DESIGN: Sera taken from hepatitis patients and individuals without liver disorders in endemic (Kirghizstan and Uzkbekistan) versus non-endemic (Moscow) areas were investigated. In parallel IgG class antibodies to hepatitis A virus (anti-HAV IgG) were determined by an enzyme immunoassay with native HAV antigen. RESULTS: In five groups comprising altogether 86 suspected hepatitis E patients from endemic area the rate of anti-HEV IgG seropositivity varied from 85% to 17%. In Moscow anti-HEV IgG was found in one patient (who also had acute hepatitis B) out of 19. Anti-HEV IgG persisted in an experimentally infected volunteer for at least 12 years after the acute disease. Among the individuals without liver disorders eight out of 173 (4.6%) showed anti-HEV IgG seropositivity in Kirghizstan while there was only one seropositive out of 165 (0.6%) in Moscow. In contrast, anti-HAV IgG were frequently present in the residents of both areas: in Kirghizstan over 90% of individuals from young age groups already had these antibodies; in Moscow the rate of anti-HAV IgG seropositivity constantly increased from 31% in the youngest age group to almost 85% in the oldest one. CONCLUSION: Prevalence of anti-HEV antibodies was unexpectedly low in endemic area; in Moscow anti-HEV IgG was found only in single cases. Anti-HEV IgG seropositivity in a single serum sample could be of certain diagnostic value in non-endemic areas.

Immunogenicity trial of inactivated hepatitis A virus vaccine in human volunteers.

An inactivated hepatitis A virus (HAV) vaccine was tested on a group of human adult volunteers. The vaccine was administered subcutaneously, and a control group received a placebo (aluminium hydroxide). The vaccine was found to be relatively well tolerated and non-reactogenic, and levels of anti-HAV were comparable to those in other studies.