Blood Donor Screening for Hepatitis E Virus in the European Union

Abstract

This review article summarises hepatitis E virus (HEV) blood donation screening strategies in effect in the European Union (EU). Since 2012, eight EU countries have implemented HEV screening. Local rates of seroprevalence, RNA incidence, and molecular epidemiology are variable and not usually directly comparable. We report a range of HEV-RNA reactivity rates from 1 in 744 donations (France) to 1 in 8,636 donations (Wales) with an overall EU rate of 1 in 3,109 donations (3.2 million donations screened). HEV genotypes 3c, 3e, and 3f are the most frequently reported subtypes. In these 8 countries, both universal (n = 5) and selective (n = 3) screening policies have been introduced utilising either individual donation (ID; n = 1) or mini-pool (MP; n = 7; MP-6, -16, -24, and -96) testing. We also describe the Irish experience of HEV screening utilising an ID-NAT-based donor screening algorithm which intercepts donations even from those with low-level viraemia; 21 of 56 donors (37.5%) had a viral load (VL) < 100 IU/mL. We performed a MP-24 experiment which may prove useful to colleagues in relation to donor screening and associated blood component transmissibility. Irish results indicate that 59% of donors with a HEV-VL < 450 IU/mL may have screened negative in a MP-24.

Keywords: European Union; Hepatitis E virus; Nucleic acid testing; Viral load.

Fig. 1

IBTS HEV blood donations screening results from January 1, 2016, to December 31, 2017, using the Procleix HEV-TMA assay. All HEV initial reactive (IR) donations were referred to the National Virus Reference Laboratory (NVRL) for molecular testing using the RealStar RT-PCR assay (Altona Diagnostics) and for anti-HEV IgM and IgG serology testing using the Wantai IgM and IgG assays (Fortress Diagnostics). All IR undergo repeat testing of 2 additional replicates (Rpt 1 and 2); if either Rpt 1 and/or Rpt 2 are reactive, a repeat reactive (RR) result is assigned. All RR undergo additional viral load and genotyping as performed by the Virus Reference Department, Public Health England (PHE), UK, and/or Department of Viral Diagnostics, Sanquin Blood Services, the Netherlands. If Rpt 1 and 2 are nonreactive after IR, a third and fourth replicate are tested (Rpt 3 and 4); non-RR (NRR; replicates 1–4 are all nonreactive). –, negative result; +, positive result; FP, false positive; WP, window period; S/CO, sample to cut-off ratio; IgM/G(–), IgM and/or IgG result negative; IgM/G(+), IgM and/or IgG result positive.

Fig. 2

Distribution of donor viral load (n = 56).