Between 1 June 2016 and 31 May 2017, 17 European Union (EU) and European Economic Area countries reported 4,096 cases associated with a multi-country hepatitis A (HA) outbreak. Molecular analysis identified three co-circulating hepatitis A virus (HAV) strains of genotype IA: VRD_521_2016, V16–25801 and RIVM-HAV16–090. We categorised cases as confirmed, probable or possible, according to the EU outbreak case definitions. Confirmed cases were infected with one of the three outbreak strains. We investigated case characteristics and strain-specific risk factors for transmission. A total of 1,400 (34%) cases were confirmed; VRD_521_2016 and RIVM-HAV16–090 accounted for 92% of these. Among confirmed cases with available epidemiological data, 92% (361/393) were unvaccinated, 43% (83/195) travelled to Spain during the incubation period and 84% (565/676) identified as men who have sex with men (MSM). Results depict an HA outbreak of multiple HAV strains, within a cross-European population, that was particularly driven by transmission between non-immune MSM engaging in high-risk sexual behaviour. The most effective preventive measure to curb this outbreak is HAV vaccination of MSM, supplemented by primary prevention campaigns that target the MSM population and promote protective sexual behaviour.

Hepatitis E virus (HEV) seroprevalences of 0.3%–53% were reported from industrialized countries. Because these estimates may be influenced by detection assays, this study compares 3 frequently used tests for HEV detection: the MP Diagnostics HEV immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA), the Axiom Diagnostics HEV IgG enzyme immunoassay (EIA), and the Mikrogen recomLine HEV IgG assay. Sera from 200 healthy healthcare workers and 30 individuals with acute HEV infection were analyzed. Among the healthy individuals, HEV IgG was found in 4.5% by the MP Diagnostics assay, in 29.5% by the Axiom Diagnostics assay, and in 18% by the Mikrogen assay. Among individuals with acute HEV infection, positive results were obtained for 83.3%, 100%, and 96.7%, respectively. Thus, the 3 assays show clear differences in diagnostic sensitivity.

We assessed hepatitis E virus (HEV) antibody seroprevalence in a sample of the adult population in Germany. Overall HEV IgG prevalence was 16.8% (95% CI 15.6%–17.9%) and increased with age, leveling off at >60 years of age. HEV is endemic in Germany, and the lifetime risk for exposure is high.