Widespread distribution of hepatitis E virus in plasma fractionation pools

摘要

We have investigated plasma fractionation pools, used in the manufacture of plasma-derived medicinal products, for HEV RNA and anti-HEV IgG. Plasma pools were obtained from Europe, North America, the Middle East and Asia. Approximately 10% of pools were positive for HEV RNA, showing a widespread geographic distribution (Table 1). Positive pools originated from plasma sourced in North America (n = 1), Western Europe (n = 2) and Eastern Europe (n = 1). No positive samples were identified in the pools from the Middle East. Of the Asian pools, four were positive for HEV RNA. None of the positive pools exceeded a load of >1000 copies/ml HEV RNA. The low viral loads found in pools may explain why Mordow et al. [1] did not detect HEV RNA in any final preparations of plasma-derived coagulation factors, which undergo further processing steps after initial cryoprecipitation. Another possible factor is the sensitivity of HEV RNA NAT assays that have been shown to vary widely between laboratories [2] and is not currently standardized. HEV viraemia in blood donors can exceed 7 log_(10) HEV RNA copies/ml [3]; therefore, dependent on pool size and virus reduction steps used during manufacture, it is possible that in HEV RNA might still be detectable in some plasma derivatives.