TY - JOUR T1 - 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 AU - Ndumbi, Patricia AU - Freidl, Gudrun S. AU - Williams, Christopher J. AU - Mårdh, Otilia AU - Varela, Carmen AU - Avellón, Ana AU - Friesema, Ingrid AU - Vennema, Harry AU - Beebeejaun, Kazim AU - Ngui, Siew Lin AU - Edelstein, Michael AU - Smith-Palmer, Alison AU - Murphy, Niamh AU - Dean, Jonathan AU - Faber, Mirko AU - Wenzel, Jürgen AU - Kontio, Mia AU - Müller, Luise AU - Midgley, Sofie Elisabeth AU - Sundqvist, Lena AU - Lundberg Ederth, Josefine AU - Roque-Afonso, Anne-Marie AU - Couturier, Elisabeth AU - Klamer, Sofieke AU - Rebolledo, Javiera AU - Suin, Vanessa AU - Aberle, Stephan W. AU - Schmid, Daniela AU - De Sousa, Rita AU - Figueiredo Augusto, Gonçalo AU - Alfonsi, Valeria AU - Del Manso, Martina AU - Ciccaglione, Anna Rita AU - Mellou, Kassiani AU - Hadjichristodoulou, Christos AB - 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. KW - hepatitis A KW - hepatitis A virus KW - men who have sex with men - MSM KW - sexually transmitted infections KW - vaccine-preventable diseases KW - vaccines and immunisation KW - 610 Medizin und Gesundheit PY - 2018 LA - eng PB - Robert Koch-Institut JO - Eurosurveillance VL - 23 IS - 33 SP - 1 EP - 12 DO - 10.2807/1560-7917.ES.2018.23.33.1700641 ER -