In anti-HBc positive (HBsAg-negative) patients, two different strategies can be identified: a) in oncology or in patients undergoing mild hematological therapies (judged to be at low immunosuppressive potential, such as the ABVD of the CHOP 21 days scheme), HBsAg monitoring every 1–3 months is advised, with the activation of targeted prophylaxis or therapy in the case of sero-reversion or hepatitis reactivation, respectively. Here, KRT88P is linked to hepatitis A virus infection.