Hepatitis a outbreak in men who have sex with men (MSM) in Brescia (Northern Italy), July 2016-July 2017

Since June 2016, an outbreak of hepatitis A has been reported in Europe. Here we report the HAV outbreak in Brescia (Northern Italy) from July 2016 to July 2017. We actively recorded all HAV cases defined by detection of HAV IgM antibodies in serum. Data on sexual behaviour, travel attitudes, concomitant sexually transmitted diseases (STDs), clinical presentation and laboratory results were collected. Forty-two confirmed cases were recorded: 25 (60%) were MSM and reported sexual contact at risk of STDs. Compared to 2015 and the first half of 2016, when only three hepatitis A cases were recorded, in the 12 months in question the number of cases rose 14-fold. Among 25 MSM, 14 were HIV-infected. Hepatitis A is usually a self-limiting disease, but it could be more serious in the case of HIV co-infection, immunosuppression and chronic hepatitis. HAV infection has a high outbreak potential in MSM because of more common oro-anal practices compared to HS, a high interconnectedness global network, chemsex practices and a new tendency to travel abroad to attend group sex events. In our experience, most cases occurred in MSM and 56% of them were HIV-infected, suggesting the need to promote active screening, immunization and education in this population.