Alavian S M et al. ed to understand the biological basis and significance of occult HBV infection better, and to clarify the possible role exerted by this cryptic infection on the outcome of liver disease and hepatocellular carcinoma develop- ment. Individuals with occult HBV infection need to be monitored by follow-up studies to assess the markers of liver damage. Anti-HBc only subjects should be carefully monitored by follow-up studies to assess the significance in various clinical settings. Mass immunization of hepa- titis B vaccine is important to control the transmission of HBV. Occult HBV infection is a frequent finding in cases with HIV/HCV co-infection making the virological sce- nario characterizing this category of patients even more complex than believed formerly. It can be expected that while the burden of chronic hepatitis B will decrease due to the introduction of more effective antiviral therapies, occult HBV infection could become a main concern. 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