HAV

Geographic areas can be divided into three types: high levels of HAV infection, intermediate levels or low levels.

High:In developing countries with poor sanitary conditions and hygienic practices, the lifetime risk of infection is very high. Most infections occur in early childhood and do not lead to any noticeable symptoms. As older children and adults are generally immune, epidemics are rarely observed. The disease rates are low and outbreaks are rare in these countries.

Intermediate: In other developing countries with improved economies and variable sanitary conditions, children escape infection in early childhood. As infections occur in older age groups, and large outbreaks can occur, these areas may have higher disease rates.

Low: In developed countries with good sanitary and hygienic conditions, infection rates are low. Disease may be found among adults in some high-risk groups, such as injecting-drug users, homosexual people, and persons travelling to high-risk areas, etc.

HBV

Hepatitis B is endemic in China and other Asian regions. Most people in the regions become infected with HBV in childhood. In these regions, 8% to 10% of the adult population are chronically infected. HBV-inducing liver cancer is among the major causes of death from cancer in people there. High rates of chronic infections are also found in the Amazon and the southern parts of eastern and central Europe. In the Middle East and Indian sub-continent, an estimated 2% to 5% of the general population is chronically infected. In Western Europe and North America, less than 1% of the population is chronically infected.

HCV

According the estimate of WHO, there are 170 million people, 3% of the world's population, infected with HCV and at risk of developing liver cirrhosis and/or liver cancer. The prevalence of HCV infection in Africa, the Eastern Mediterranean, South-East Asia and the Western Pacific (when prevalence data are available) is significantly higher than North America and Europe.