[On the detection of HBV cccDNA and its clinical significance: an overview of research advancement].

Covalently closed circular DNA (cccDNA) is the existing form of the HBV DNA in the nucleus of host cells and also the original template of HBV replication; its long-term presence in the nucleus makes it difficult to be eliminated by current antiviral drugs; and it becomes the key factor of continuous HBV infection and relapse after antiviral suspension. Detection of HBV cccDNA is of great significance for further understanding the life cycle of HBV and providing guidance for antiviral treatment. This article aims to review the detection and its clinical significance to the advancement of researches on hepatitis B virus cccDNA.