Chronic HBV infection affects over 257 million people globally and leads to cirrhosis and liver cancer. Prevalence varies greatly with geographic locations. In areas where the prevalence is high, such as Southeast Asia, China, and Africa, more than half the population is infected at some time in their lives.
HBV is an enveloped, partially double-stranded DNA virus. It is transmitted percutaneously, sexually, and perinatally. HBV infection symptoms including fatigue, malaise, nausea, abdominal pain, dark urine, and jaundice will occur from 30 days to 6 months after the exposure.
The diagnosis of HBV infection requires the evaluation of several biomarkers including hepatitis B surface antigen (HBsAg), anti-HBs, hepatitis B core antibody (IgM and IgG), hepatitis B e antigen (HBeAg) and anti-HBe. Serum hepatitis B surface antigen (HBsAg) is a marker of HBV infection, and antibodies against HBsAg signify recovery. A serum marker of active viral replication, hepatitis B e antigen (HBeAg), is accompanied by serum levels of HBV DNA. The presence of HBsAg indicates that the person is infected by the virus.