Seroprevalence of IgM and IgG Antibodies Directed Against Hepatitis E Virus in 4867 Blood Donors From Tyrol, Austria

There may be a risk of transmitting Hepatitis E Virus (HEV) through blood transfusions, however screening blood donors for HEV is not mandatory in Austria. We assessed the seroprevalence of anti-HEV antibodies among blood donors, thereby informing about the risk of HEV-contaminated blood products. Between May and July 2022, we enrolled 4867 blood donors aged 18-70 years at 38 donation events spread across the Federal State of Tyrol, Austria. We measured anti-HEV IgG and IgM antibodies using five validated assays, based on which overall anti-HEV seropositivity was defined. We determined seroprevalences with 95% confidence intervals (CI) and calculated odds ratios for seropositivity using logistic regression. Median age of participants was 45.99 years (25th-75th percentile: 31.49-55.80); 41.15% were female, and 75.82% lived in rural areas. Anti-HEV IgM was detected in 13 individuals, i.e. 0.27% (95% CI: 0.16-0.47%). Anti-HEV IgG seroprevalence was 19.26% (18.17-20.40%) overall. It was higher in older blood donors - peaking in the 65-70-year age group (47.92%) -, higher in males (20.70%) than females (17.20%) and higher in urban (21.28%) compared to rural areas (18.61%). Multivariable adjusted odds ratios for IgG seropositivity were 1.19 for male sex (1.01-1.39; p = 0.033), 2.15 per 10-year older age (2.00-2.30; p < 0.001) and 1.21 for residing in an urban area (1.02-1.45; p = 0.030). Our findings indicate that HEV is widespread in Austria. Implementation of mandatory routine HEV nucleic acid testing should be considered in blood donations to enhance transfusion safety.