Hepatitis E virus as a transfusion transmitted infection-current status

Abstract

Objectives: Hepatitis E virus (HEV) infection is growing worldwide and presents a new threat to the blood transfusion services across the world. The present review tries to explore how the transfusion medicine community is responding to the threat. Materials and Methods: The major papers and important case reports were culled from PubMed, Science Direct, Embase related to this infection, and transfusion medicine since 2005 were explored and relevant articles were discussed with emphasis on epidemiology, infection, prevalence in donor population, susceptible recipients, prevention, and future development. Results: There are eight genotypes of this virus with different host, transmission biology, and clinical infection. Chronic infections are more common with Genotype 3 and Genotype 4 which are prevalent in Europe and transmitted by pig and meats cooked from this animal. Genotype 5 and 6 has not yet been linked to human transmission. Genotype 1 and Genotype 2 cause epidemic form of this infection and are common in developing countries. Immunosuppressed and chronic liver disease patients get chronic or severe infection. Pregnant ladies develop fulminant hepatitis with high mortality. The virus is transmitted by blood products but severe infection is uncommon. Many European countries, USA, Canada are using Nucleic Acid Testing (NAT) based technology to screen their donors as Individual Donor-NAT or Minipool NAT with varying efficiency. Large part of the world as yet has not taken any active measure to contain this infection through transfusion. A vaccine is available, effective but is not widely used as more studies are needed. Cross immunity does happen between genotypes and presence of immunoglobulin G antibody in blood protects against serious infection. Alanine transaminase level corresponds with viremia in asymptomatic but infected individuals. Conclusion: The HEV is an emerging but important threat to transfusion medicine service. Important information regarding this infection is still lacking. However, there is a need to develop robust safety algorithm to counter this threat and make transfusion safer.