Hepatitis E viral loads in plasma pools for fractionation

BACKGROUNDIt is now recognized that blood donors may be silently infected with hepatitis E virus (HEV) and that plasma pools used in the manufacture of plasma-derived medicinal products may also contain detectable virus RNA. The occurrence of HEV-infected blood and plasma donors can vary considerably depending on local epidemiology. STUDY DESIGN AND METHODSManufacturing plasma pools from North America, Europe, the Middle East, and Asia were examined for the presence of HEV using transcription-mediated amplification of HEV RNA; confirmatory testing was performed using real-time reverse transcription polymerase chain reaction and sequencing. RESULTSA total of 484 pools were tested. Asian pools were most frequently positive for HEV RNA and had higher viral loads, although none exceeding 300 IU/mL, and the sequenced strains (n=5) clustered with Genotype 4, including one significantly divergent sequence. Only HEV Genotype 3 was identified in North American (n=5) and European (n=5) pools. There was no evidence of HEV in any pools tested from the Middle East. CONCLUSIONSHEV was detected in manufacturing plasma pools from three different continents; viral loads were lowconsistent with large pool sizes and moderate levels of HEV viremia at the individual donation levelbut are nevertheless informative for risk assessment of plasma-derived medicinal products. Where sequencing was possible, analysis confirmed the presence of viruses consistent with locally circulating genotypes in the respective regions. The absence of HEV in Middle Eastern pools is consistent with the low prevalence of HEV in this region, likely due to low pork consumption.