epidemiology

Last edited 06/2018 and last reviewed 03/2022

epidemiology

An estimated 2 billion people around the world have evidence of past or present infection with HBV.

  • out of this, around 240 million are chronic carriers of HBV surface antigen (HBsAg)

    • age-specific HBsAg seroprevalence varies markedly by geographical region
      • highest prevalence (>7%) - China, South East Asia, Africa, the Pacific Islands, parts of the Middle East, and the Amazon basin.
      • intermediate prevalence (2-7%) - south central and southwest Asia, eastern and southern Europe, Russia, Central America, and South America
      • low prevalence (<2%) - primarily the US, western Europe, Australia, and Japan

  • around 1 million people die each year due to chronic HBV (CHB) and its complications (cirrhosis and primary liver cancer)
    • 15-40% of chronically infected patients will develop cirrhosis, progressing to liver failure and/or HCC during their lifetime
    • nearly 50% of the mortality secondary to hepatocellular carcinoma (HCC) in 2010 was associated with HBV.
  • every year, there are over 4 million acute clinical cases of HBV (1,2,3)

Overall, approximately 45% of the global population live in areas of high endemicity. With globalization, many individuals with HBV are immigrating to areas in which the CHB rate has traditionally been low and the condition may easily go unnoticed (2).

Perinatal transmission is the main mode of transmission in countries with high prevalence while sexual exposure is principally responsible in low prevalence countries (2).

In the UK, there is evidence that Chinese-born immigrants may have a seven-fold risk of carrying hepatitis B compared with other UK residents (1). A retrospective study looking at the prevalence of hepatitis B in 117 Chinese and 234 non-Chinese patients attending two genitourinary medicine clinics in London revealed that about 40% of non UK-born Chinese had serological markers for hepatitis B (compared with 5.5% of controls and 6.7% of UK-born Chinese).

Reference: