Hepatitis A outbreak disproportionately affecting men who have sex with men (MSM) in the European Union and European Economic Area, June 2016 to May 2017.

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: Assessment of the epidemiological situation in humans in Europe, 2014/15.

BACKGROUND: Hepatitis E virus (HEV) is endemic in EU/EEA countries, but the understanding of the burden of the infection in humans is inconsistent as the disease is not under EU surveillance but subject to national policies. STUDY: Countries were asked to nominate experts and to complete a standardised questionnaire about the epidemiological situation and surveillance of HEV in their respective EU/EEA country. This study reviewed surveillance systems for human cases of HEV in EU/EEA countries and nominated experts assessed the epidemiology in particular examining the recent increase in the number of autochthonous cases. RESULTS: Surveillance systems and case definitions across EU/EEA countries were shown to be highly variable and testing algorithms were unreliable. Large increases of autochthonous cases were reported from Western EU/EEA countries with lower case numbers seen in Northern and Southern European countries. Lack of clinical awareness and variability in testing strategies might account for the observed differences in hepatitis E incidence across EU/EEA countries. Infections were predominantly caused by HEV genotype 3, the most prevalent virus type in the animal reservoirs. CONCLUSION: Discussions from the expert group supported joint working across countries to better monitor the epidemiology and possible changes in risk of virus acquisition at a European level. There was agreement to share surveillance strategies and algorithms but also importantly the collation of HEV data from human and animal populations. These data collected at a European level would serve the 'One Health' approach to better informing on human exposure to HEV.