PREVALENCE OF AND RISK-FACTORS FOR ANTIBODY TO HEPATITIS-E VIRUS SEROREACTIVITY AMONG BLOOD-DONORS IN NORTHERN CALIFORNIA

To evaluate antibody to hepatitis E virus (anti-HEV) seroreactivity, 5 000 US blood donors were tested for anti-HEV by two EIAs: a mosaic pro tein assay (MPr-EIA) and a recombinant protein assay (RPr-EIA). Overal l, 59 (1.2%) were seroreactive by MPr-EIA and 70 (1.4%) were seroreact ive by RPr-EIA, The overall concordance between tests was 98.5% (4925/ 5000); the concordance among reactive sera by either test was only 27% (27/102). In a case-control study, seroreactive persons were more lik ely than seronegative persons to have traveled to countries in which H EV is endemic (odds ratio [OR] for MPr-EIA = 4.3, P < .001; OR for RPr -EIA = 2.5, P = .005), but 31% of MPr-EIA anti-HEV-reactive persons an d 38% of RPr-EIA anti-HEV-reactive persons had no history of internati onal travel, These findings suggest that travelers to regions in which HEV is endemic can acquire subclinical HEV infection. The significanc e of anti-HEV seroreactivity among persons without an international tr avel history needs to be determined.