Natural history of chronic hepatitis B: Phases in a complex relationship

Table 1 Geographical variation in hepatitis B prevalence and patterns of transmission[8]

Pattern of prevalence	Geographical area	Percent of population HBsAg positive	Predominant age at infection	Predominant mode of transmission
High ≥ 8%	Southeast Asia, China, Pacific Islands, Sub- Saharan Africa	8%-20%	Perinatal and early childhood	Maternal-infant, percutaneous (e.g., unsterile medical equipment used in vaccination, traditional medicine practices)
Intermediate 2%-7%	Eastern Europe, the Mediterranean basin, Middle East, Central and South Asia, Japan, Central and South America	2%-7%	Early childhood/adolescence	Percutaneous (e.g., horizontal transmission between children through open wounds/cuts), sexual
Low < 2%	United States and Canada, Western Europe, Australia and New Zealand	0.2%-0.5%	Adult	Sexual, percutaneous (e.g., intravenous drug use)

HBsAg: Hepatitis B surface antigen.