[Re-recognition of occult hepatitis B virus infection].

Hepatitis B virus (HBV) infection remains to be a serious public health problem in China. There used to be a high prevalence of HBV infection in China, which resulted in a large number of HBV susceptible and post-infected population. Single anti-HBc positive usually indicates post HBV infection and its prevalence is particularly high among people over 40 years old, some of whom may be occult hepatitis B virus infection (OBI). The clinical diagnosis of OBI is difficult and easily missed. Since OBI may cause chronic liver disease progression and even lead to cirrhosis and hepatocellular carcinoma eventually, and more importantly, patients with OBI may leed to HBV reactivation when the immune function decreases or immunosuppressive therapy is performed, the accurate identify of OBI is of particular importance. Moreover, OBI is the potential source of HBV infection, which may transmit through blood transfusion, organ transplantation and mother-to-child transmission. In view of this situation, we reviewed the mechanism, prevalence and definition of OBI, and proposed a determination system for replication-competent HBV DNA based on our understanding of the updated OBI definition. It is expected to be beneficial for OBI diagnosis, treatment and management.