Hepatitis E screening for blood donations: an urgent need?

www.thelancet.com Vol 384 November 15, 2014 1729 In The Lancet, Patricia Hewitt and colleagues report the prevalence of hepatitis E virus (HEV) RNA in 225 000 blood donations from southeast England. Their study was based on HEV RNA detection by means of reverse transcriptase real-time PCR in minipools of 24 donations or fewer collected in a 1-year period (2012–13). They defi ned the rate of transmission from HEV-containing blood components, investigated the factors associated with transmission, and looked at the outcomes of recipients of HEV-containing blood components. HEV RNA was noted in roughly one in every 2848 (0·04%) blood donations tested. When projected across England, this prevalence suggests that about 80 000–100 000 acute HEV infections are likely to have occurred countrywide during the year of the study. Overall, 79 HEV genotype 3 RNA-positive donations, 56 of which (71%) were seronegative, were used to prepare 129 blood components; 62 were transfused, resulting in 18 documented infections (42%) among the 43 recipients who could be followed up. The components associated with transmission included platelet preparations, red cells, granulocyte pools, and fresh frozen plasma. The median times for seroconversion and duration of infection depended on the degree of immunosuppression. Ribavirin treatment was started in one severely immunosuppressed infected recipient, and the level of immunosuppression was reduced in one moderately immunosuppressed patient and one severely immunosuppressed patient, to induce viral clearance. Among the other patients, four died, one remained viraemic, and the remaining infections cleared spontaneously. These results are interesting and can inform the ongoing debate about HEV and blood safety. The HEV genome was cloned in 1990 and this virus was identifi ed as the main causative agent of enterally transmitted non-A, non-B hepatitis. Four genotypes, 1 to 4, have subsequently been identifi ed in human beings. HEV was initially thought to be present mainly in low-income or middle-income areas, where poor hygiene conditions favour faecal–oral transmission of genotypes 1 and 2, resulting in frequent sporadic cases and large outbreaks of acute hepatitis related to the contamination of drinking water. More recently, HEV genotypes 3 and 4 were reported as zoonotic infections in the developed world, causing acute hepatitis cases in occupationally exposed individuals or consumers of infected meat that had been insuffi ciently cooked. Acute hepatitis E is generally mild and self-limiting. However, HEV infection is not always harmless. Severe cases, including subfulminant or fulminant hepatitis, have been reported in patients with underlying chronic liver disease. HEV infection can induce various types of eventually severe extrahepatic manifestations, such as neurological symptoms, kidney injury, pancreatitis, or thrombocytopenia, and aplastic anaemia; a higher mortality owing to HEV infection has been reported in pregnant women than in the general population during large outbreaks in low-income areas, the causes of which remain debated. Chronic HEV infection has been reported in immunocompromised patients, including recipients of solid organ transplants and haemopoietic stem cell transplants, patients receiving chemotherapy, HIV-infected individuals, and patients taking steroids. Chronic HEV infection can cause chronic liver disease that rapidly evolves towards cirrhosis in roughly 10% of cases, with a risk of lethal liver failure. Blood transfusion is known to be a route of HEV transmission in immunocompromised patients. We recently reported in The Lancet that 5 of 367 consecutive liver transplant recipients (1·4%) acquired chronic hepatitis E through blood transfusion and subsequently developed persistent liver graft damage. The prevalence of HEV RNA in blood donations in England reported by Hewitt and colleagues is in keeping with fi ndings from studies in other European countries (one in 1240 donations in Germany and one in 1761 donations in the Netherlands). Despite this high prevalence, the high rate of transmission by infected blood or blood products, the non-negligible morbidity and mortality related to HEV infection (especially in patient populations exposed to blood or blood product transfusion), and the lack of effi cient antiviral therapy, Hewitt and colleagues surprisingly conclude that “there seems no pressing need to move rapidly with the introduction of donation screening”. Hepatitis E screening for blood donations: an urgent need?