Covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is the template for HBV replication. Currently, there is a lack of therapeutic drugs that directly target cccDNA. Therefore, blocking cccDNA supplements as fast as possible and reducing the existing cccDNA is the key to achieving a complete cure of chronic hepatitis B. Previous studies have suggested that cccDNA had a long half-life, but a recent study showed that it only took a few months to update cycle of cccDNA pool, and its number was much less than previously predicted. In the future, with the advent of new antiviral drugs that can completely inhibit HBV replication, it is expected that the cccDNA pool will be completely cleared due to its supplement complete blockade, so as to achieve virological cure of chronic hepatitis B.
乙型肝炎病毒（HBV）共价闭合环状DNA（cccDNA）是HBV复制的模板，在缺乏直接靶向cccDNA治疗药物的情况下，阻断cccDNA的补充并尽快耗竭已有的cccDNA是实现慢性乙型肝炎彻底治愈的关键。既往研究认为cccDNA的半衰期很长，但近期的一项研究结果提示cccDNA池的更新周期仅为数月，远低于之前的预测。未来，随着新的、能够完全抑制HBV复制的抗病毒药物出现，cccDNA池将有望因其补充被完全阻断而被彻底清除，进而实现慢性乙型肝炎的病毒学治愈。.
Keywords: Chronic hepatitis B; Clinical cure; Covalently closed circular DNA; Half-life period; Hepatitis B virus; Therapy; Virologic cure.