Sub-Saharan regions of Africa have very high levels of HBV prevalence particularly in western sub-Saharan African countries with up to 12 % of children and adolescents below 19 years of age being infected [18]. Since the first evaluations conducted in the late 1980s and 1990s, significant decreases in the HBsAg prevalence have been documented in 2005 in African countries such as the Gambia and Senegal [18]. In Eastern and Southern sub-Saharan Africa, the situation is more confusing showing an increase in chronic HBV infection among younger age groups (0–14 years), with age-specific prevalence rates of 7–9 % among young females and a prevalence peaking at about 7 % in 0–4 years old children, a decline in older age groups and almost no change in other age groups [18]. This situation may be related to the inadequate implementation of immunization programs in some countries [51]. A decrease in prevalence was evident in Central sub-Saharan Africa which transitioned from high endemicity among younger individuals (age-groups up to 34 years) in 1990 into intermediate endemicity across all ages in 2005 [18].

North Africa showed a lower intermediate HBsAg endemicity across all age groups in 2005 with a decrease in prevalence from 1990 to 2005, particularly among males up to 34 years.

The prevalence in the high-income countries of North America (Canada and the USA) was low and declined in both sexes and across all ages between the 1990s and 2005. Males had higher HBsAg positivity than females in both periods, peaking in the male 0–4 years age group at 2.7 % and 2.1 % in the 1990s and 2005, respectively. The oldest ages (65+ years) showed the lowest prevalence of approximately 1 % in 2005. However, one should note that special population groups might have a high prevalence [52–57].

Both Tropical Latin America and Central Latin America demonstrated a strong decrease in HBsAg prevalence between the 1990s and 2005. Tropical Latin America changed from an intermediate into a low endemicity region. In 1990, 0–9 year aged boys had a higher intermediate HBsAg prevalence endemicity of over 5 %, in 2005 it was only 1.6 %. Similarly, in Central Latin America prevalence has halved in this period and most adult age groups shifted to low endemicity levels in 2005. A slight decline in prevalence from the 1990s to 2005 among Andean Latin Americans was paralleled by an increase in HBsAg prevalence in Southern Latin America. In Caribbean countries children and adolescents aged 0–19 years HBsAg prevalence was rather constant over time ranging from 4.3 to 5.4 % [18, 58, 59].

In Asia , East Asia has the highest prevalence of HBV infection, with a minor decrease in children and an increase in all age groups above 25 years reported in the 1990s to 2005 comparison, and the highest prevalence of >8 % found in males aged over 35 years. An intermediate HBsAg endemicity was reported in Central Asian children and younger adults with a HBsAg prevalence of ~5 %, where a small decrease was observed between the 1990s and 2005. In South Asia, approximately 3 % of the population younger than 45 years of age was HBsAg positive, while in older individuals a decrease was demonstrated and the prevalence was low in 2005 [18]. One should note, that Asian countries put tremendous efforts to increase the routine coverage of infant hepatitis B immunizations leading to the reported reductions in HBsAg prevalence. The impact of the decrease in HBsAg prevalence was also linked to a substantial reduction in the HBV-related disease burden in China [60], Japan [61], Malaysia [62] and Taiwan [63, 64]. The seroprevalence of HBV infection reported in India is >5 %, but population based data are scarce and therefore the information may be misleading in this country of >1 billion people, with figures varying from 2 to 11 % [65], thus having potentially a major impact on the HBV global figures [66, 67]. In South East Asia, a reduction was also reported in the age group 0–14 years with prevalence of ~1.4 % in 2005. Adults continued to have higher-intermediate HBsAg prevalence of 5 to >6 % [18].

The global burden of disease from hepatitis B is largely driven by the situation in China because of its massive population and high endemicity. Remarkable progress has been made in China with hepatitis B immunization of children, lower horizontal child-to-child transmission because of their single child policy, and safer injections. These factors have reduced the HBsAg prevalence in immunized cohorts of children from approximately 10 to 1 %. It is estimated that China has about 9.8 % chronic carriers and 300,000 deaths from cirrhosis and liver cancer [68–70].

In Japan, the Republic of Korea, and Singapore, endemicity remained at a lower intermediate level around 4 % in 2005 with subjects aged 25–54 being the most affected [18].

In Australia the prevalence of chronic HBV is estimated around 1 %, including a majority of subjects born abroad, or belonging to Aboriginal and Torres Strait Islander communities. However, the disparity between indigenous and nonindigenous people has decreased since the implementation of the HBV vaccination program in 2000 [71–73], but the need for HBV screening remains in order to identify people who would benefit from vaccination or treatment [74].

For the islands of the Pacific and Indian Oceans (Oceania), a geographically, culturally, and socioeconomically highly heterogeneous region, data are again limited and often of questionable quality. A moderate to high endemicity for HBsAg of 5–7 % is assumed [75].

A wide variation in the prevalence of HBsAg between countries in Europe is reported [76], a finding that has not changed over time. In Western Europe, seroprevalence of HBsAg was consistently low and consistently lower in females [76, 77]. Central and Eastern European children had a higher intermediate HBsAg endemicity with a decrease observed in 2005, especially among elder Central European females. Prevalence in infant and young girls declined from 6 % in the 1990s to 3 % in 2005. In contrast, the youngest age groups of Eastern European countries showed a limited reduction in HBsAg prevalence. In Central and Eastern Europe the age group 0–9 years remains the most affected [77].

The prevale nce of hepatitis B infection in the Middle East varies among its geographic areas significantly from 0.3 to 7 % [22, 78]. The prevalence of HBsAg has declined significantly in most Middle East countries, especially Saudi Arabia, Egypt and Iran during the last two decades [79–81]. There can be considerable differences in the prevalence of HBV infection within individual countries. Such a variability has been observed in Turkey (<2–8 %), Pakistan, and the Yemen, with higher prevalences in rural and/or poorer communities [22].

Mobile populations present unique health care concerns for society and for HBV in particular. Although travel and immigration is an old phenomenon, today an increasing number of people are on the move, and the demography of these mobile populations is changing and becoming more heterogeneous, dynamic and complex. Forced and voluntary mass migration involves hundreds of millions of people each year and it is estimated that two to four million people migrate permanently each year. Generally, populations flow from developing to developed countries , from east to west, from south to north, and from high to low HBV endemicity regions. Metropolitan areas are the main recipients of migrants in all countries concerned [82].

While HBsAg prevalence is low in Western European countries, the epidemiological situation is changing because of high rates of immigration from high and intermediate endemicity areas. The low fertility in many Western European populations has led to a situation where a large proportion of births in large cities are to immigrant mothers from endemic areas. Several Nordic countries and the UK do not do routine childhood hepatitis B immunization and most of their children and young adults are susceptible to hepatitis B infection.

Persons from high-risk populations , especially immigrants from nations where hepatitis B is highly endemic, should be tested for HBV and should be vaccinated if they are found to be negative. Equitable access to and availability of quality, effective, affordable, and safe diagnostics and treatment regimens for HBV are lacking in many countries from which migrants move out. Country-specific HBV data to target these most vulnerable population groups will be crucial for implementing national HBV prevention and control programs . The elimination of stigmatization and discrimination against people living with HBV are warranted and policies for equitable access to prevention, diagnosis and treatment for HBV must be applied to indigenous people, migrants and vulnerable groups.

Europe and North America face great geographical variation with higher prevalence and higher hepatitis-related mortality among migrants [82, 83]. Many countries have only in the last decades received migrants on a mass scale and are therefore not prepared to deal with these important populations moves. Europe is a primary destination for many spontaneous or undocumented illegal workers, refugees, asylum seekers, and people who are victims of trafficking. These people face poverty, limited access to health care, and low sympathy and acceptance from the host population.

In addition to migration, international adoption has become increasingly common due to the decline in children offered for adoption in the USA and Europe . This relatively new phenomenon became more pronounced after World War II. As an example, in the USA international adoptions increased from 4864 to 16,000 between 1979 and 1998 [84]. Many adopted children come from high endemic areas such as Eastern Asia (e.g., China, Vietnam), sub-Saharan Africa, South America and from countries of the former Soviet Union, where HBsAg prevalences range from 2 to 15 %. These adopted children have a much higher HBsAg carrier rate than the general population in the countries of adoption [84–87]. Families considering intercountry adoption should be made aware that the child may need to be immunized before it arrives in its new family. The child should also be tested for HBV upon arrival in the country of adoption.

Although great progress in hepatitis B control is being made in many areas, the infection in drug users is still a major public health problem in both the industrial and developing worlds and transitional economies such as the former Soviet Union where the problem of drug use and resultant viral infections is increasing in many areas. HBV is highly transmitted through needle and paraphernalia sharing. 1.2 million of the 16 million people injecting drugs are chronically infected with HBV [88]. The WHO recommends that injecting drug users (IDUs) need to be specifically targeted for prevention and treatment of viral hepatitis [89]. Reduction of risky behaviors and risk reduction strategies such as needle exchanges secondary to HIV/AIDS control efforts have reduced the prevalence of HBV infections in some drug using populations. Efforts to immunize drug users with HBV vaccine have been problematic since drug users are often already infected by the time they are reached by immunization programs and often have little motivation to participate in HBV immunization programs.

Because HBV is highly transmissible sexually, transmission between sexual partners is both an important cause of HBV infection, and is one of the most frequent sexually transmitted infections [90–93]. However, most persons with chronic HBV infection are not aware that they are infected and these silent carriers are an important and difficult to identify source of infection: this is particularly true for sex workers [94–98]. Men who have sex with men (MSM) are one of the groups at highest risk for HBV infection, especially if they engage in high-risk sexual practices [90]. It is mandatory that these populations are targeted for prevention activities and that susceptible individuals receive HB vaccination.

Globally, there a re more than three million people coinfected with HBV and HIV. Coinfection is associated with more rapid progression of liver disease and consequential high morbidity and mortality [99, 100]. People at risk of HIV infection, should be counseled about HVB (and also HCV) coinfection probabilities and dangers and should be considered for receiving effective antiviral therapies for both HIV and HBV.

Organ transpl ant recipients , hemophiliacs and patients on hemodialysis disserve special care and attention. Although these groups, due to their limited population size, play a lesser role from a global perspective, the high incidence and prevalence of HBV in some of these groups make it mandatory to offer them special consideration.