Carey William D
Cleveland Clinic Lerner College of Medicine, Digestive Disease Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
Cleve Clin J Med. 2009 May;76 Suppl 3:S2-5. doi: 10.3949/ccjm.76.s3.01.
The prevalence of chronic hepatitis B virus (HBV) infection varies by geographic region. Most of North America is a low-prevalence (< 2%) area. Certain high-prevalence pockets exist, especially areas with a high proportion of Asian immigrants and Alaskan and northern Canadian native populations, where rates of chronic HBV are as high as 5% to 15%. In most low-prevalence areas, HBV infection is acquired mainly during adolescence and midadulthood, whereas perinatal transmission is the main route in high-prevalence (> or = 8%) areas. Up to 40% of patients with chronic HBV infection develop liver complications. Age at acquisition affects the likelihood of chronicity and the development of liver complications. The risk of each is greatest with perinatal transmission; the disease is usually self-limiting when exposure to HBV occurs during adolescence or young adulthood. Viral load predicts progression to cirrhosis and hepatocellular carcinoma; therefore, reducing viral load is the major goal of treatment.
慢性乙型肝炎病毒（HBV）感染的流行率因地理区域而异。北美大部分地区是低流行率（<2%）地区。存在某些高流行率区域，特别是亚洲移民比例高的地区以及阿拉斯加和加拿大北部原住民地区，这些地区慢性HBV感染率高达5%至15%。在大多数低流行率地区，HBV感染主要在青春期和成年中期获得，而围产期传播是高流行率（≥8%）地区的主要传播途径。高达40%的慢性HBV感染患者会出现肝脏并发症。感染时的年龄会影响慢性化的可能性以及肝脏并发症的发生。围产期传播时这两种情况的风险最大；在青春期或青年期接触HBV时，疾病通常是自限性的。病毒载量可预测肝硬化和肝细胞癌的进展；因此，降低病毒载量是治疗的主要目标。
