Monophyletic outbreak of Hepatitis A involving HIV-infected men who have sex with men, Rome, Italy 2008-2009

The outbreak occurred in Rome in 2008-2010, involving high proportion of HIV-infected MSM, is sustained by a monophyletic HAV strain, circulating around the same period also in other European countries. Possible factors favouring HAV spread among HIV-infected persons, such as high risk behavior and prolonged fecal excretion, need to be further elucidated. Timely identification of outbreaks with one or the same source of infection may be helpful to implement preventive measures addressing at risk populations.