Hepatology Clinical

It is estimated that approximately 30% of the world's population has had contact
with or are carriers of the hepatitis B virus (HBV). An estimated 350 million of
them are HBV carriers (Goldstein2005). Thus, HBV infection is one of the most
important infectious diseases worldwide. Around one million persons die of HBVrelated
causes annually. There is a wide range of HBV prevalence rates indifferent
parts of the world. HBV prevalence varies from 0.1% up to 20%. Low prevalence
areas (0.1-2%) are Western Europe (with wide variation within Europe), United
States and Canada, Australia andNew Zealand; intermediate prevalence (3-5%) are
the Mediterranean countries, Japan, Central Asia, the Middle East, and Latin and
South America; and high prevalence areas (10-20%) include southeastAsia, China,
and sub-Saharan Africa. This diversity is probably related to differences in age at
infection, which correlates with the risk of chronicity. The progression rate from
acute to chronicHBV infection decreases with age. It is approximately 90% for an
infection acquired perinatally, and is as low as 5% (or even lower) for adults
(Stevens 1975, Wasley 2008).
The incidence of newinfections has decreased in most developed countries, most
likely due to the implementation of vaccination strategies (Rantala 2008). However,
exact data is difficult to generate as many cases remainundetected due to the
asymptomatic nature of many infections (RKI 2007, CDC 2010). Nevertheless, in
Germany 2524 cases of acute hepatitis B were documented in the year 2006,
corresponding to anincidence rate of 1.4 per 100,000 inhabitants. In 1997 there
were 6135 documented cases of acute hepatitis B. Likewise, the incidence of acute
hepatitis B in the United States has decreased dramaticallyfrom 1990 to 2010
(Wasley 2008, CDC 2012). It is expected that this number will further decrease in
countries with implementation of vaccination programs. In Germany 87% of all
children starting...