Outbreak of acute hepatitis A associated with men who have sex with men (MSM) in North Sardinia 2017-2018.

Introduction: We describe an outbreak of hepatitis A among men who have sex with men (MSM) which evolved in Sassari (Italy), between January 2017 and December 2018, close to a contextual of large concurrent hepatitis A outbreak reported in Europe and recently, in Italy. Methodology: HAV RNA detection and molecular characterization was performed from serum samples and/or stool by RT - PCR of VP1/2A junction region that ranges from nt. 2,873 to nt. 3,376. The phylogenetic correlation of the circulating hepatitis A strains was assessed by sequencing method according to the HAVNET protocol. Results: 10 Acute Hepatitis A virus (AHA)-positive cases, 8 of which were among men who have sex with men (MSM) were identified. All patients were tested at the time of hospitalization for the presence of anti-HIV antibodies, only two MSM resulted co-infected by HIV. No differences were observed in median age (37 years vs. 41 years, P-value = 0.14), severity or duration of hospitalization between seropositive and HIV-negative men. Phylogenetic analysis was conducted in 2 cases and revealed two distinct sequences of genotype IA linking to clusters recognized in MSM in other European countries in 2016. Conclusion: Our study reported a recent increase of notified hepatitis A cases attributable to cases in the European interconnectedness of MSM in Sassari, a small locality. Hepatitis A vaccination for MSM in Sardinia region is recommended; however, our data emphasize the need of hepatitis A screening and vaccination not only for MSM with occasional partners but also for those in monogamous relationships.