Risk of a blood donation contaminated with hepatitis E virus entering the blood supply before the implementation of universal RNA screening in France

Background and objectives: The risk of a blood donation contaminated with hepatitis E virus (HEV) entering the blood supply before introducing universal HEV-RNA screening in France was estimated to assess the benefit of such a measure.

Materials and methods: The results of selective HEV nucleic acid testing (HEV-NAT) performed in mini pool of six plasma donations between 2018 and 2020 were extrapolated to the whole blood donor (BD) population after adjustment on three variables: regional establishment, sex and age group.

Results: Among the 246,285 plasma donations collected from 172,635 BDs tested for HEV-RNA, 248 (10.1/10,000) were positive. The extrapolation to all BDs led to an estimated rate of 5.9/10,000 donations (95% confidence interval [CI]: 4.5-7.4) which would be positive to HEV-RNA and a prevalence of 9.9/10,000 BDs (95% CI: 7.5-12.3). This prevalence was 4.4 times higher in males than females (16.8/10,000 vs. 3.8/10,000, p < 10^-4 ). The highest prevalence was observed in males in the 30-39 age group (20.5/10,000) and the lowest in females in the 50-70 age group (2.8/10,000).

Conclusion: The risk of an HEV-RNA-positive donation entering the blood supply was estimated at 1 in 1682 donations. This risk does not translate directly to the risk of HEV transfusion transmission, which mainly depends on the total number of viral particles in the transfused blood component and the sensitivity of NAT.