Seroprevalence and incidence of hepatitis E virus infection in German blood donors.

BACKGROUND: Hepatitis E virus (HEV) is transmissible by transfusion. More data are needed about seroprevalence, incidence, and viremia in blood donors for the assessment of risk of transfusion-transmitted (TT)-HEV infections. STUDY DESIGN AND METHODS: Samples from 1019 whole blood donors were tested for anti-HEV immunoglobulin (Ig)G by enzyme-linked immunosorbent assay and Western blot. The incidence of HEV and presence of HEV RNA in donors who seroconverted were determined by testing archive samples and recipients of viremic donations were traced. Anti-HEV IgM and alanine transaminase (ALT) testing were also performed to assess the value of such measures in the prevention of TT-HEV infections.
RESULTS: A total of 69 of 1019 donors tested positive for anti-HEV IgG (6.8% seroprevalence), and seroconversion for anti-HEV IgG occurred in seven of 69 donors within 2 years (incidence, 0.35%/year). Three of seven (42.8%) seroconverting donors provided an archive sample in which HEV RNA was detectable. One recipient of these donations was traceable; anti-HEV IgG, IgM, and HEV RNA testing were negative 41 days after transfusion. Neither ALT levels nor anti-HEV IgM detection correlated with the presence of HEV RNA.
CONCLUSIONS: The seroprevalence of HEV was 6.8%, and the annual incidence 0.35%. HEV RNA was detectable in several seroconverting donors, without evidence for HEV transmission in the only traceable recipient. Since neither ALT nor anti-HEV IgM testing correlate with the presence of HEV RNA, HEV nucleic acid testing currently provides the only method for the prevention of TT-HEV infection. However, before implementation, more data about clinical relevance of TT-HEV infections and infectious dose of HEV are required.