Hepatitis B virus, HBV infection, is a major global health problem. The worldwide prevalence of HBsAg positivity is estimated to be 3.6 percent. The prevalence varies among different regions. The [inaudible] prevalence can be found in most African, Western Pacific, including China and Taiwan and some Southeastern Asian regions where the prevalence is as high as eight to 15 percent. Regarding the global distribution of HBV infection, more than 2 billion people have been infected with HBV. Two hundred and forty eight million people suffer from chronic HBV infection, and this problem, chronic HBV infection, accounts for around 30 of all cirrhosis and 53 of the hepatocellular carcinoma. Eventually, above 15 to 25 percent of chronic HBV infection patient will die from these comorbidities. The major complication of chronic HBV infection is liver cirrhosis and hepatocellular carcinoma. Several viral factors such as HBV antigen status, high HBV viral loads and HBV genotypes are associated with the development of HCC. Besides, some host factors including age, gender, family history of HCC, alcohol consumption, and hepatic inflammation fibrosis also have contributions. In major history of HBV infection there are two major routes of HBV transmission. One is perinatal infection, the baby gets the virus from their mothers during the early intrauterine life, or during the delivery process, or shortly after birth. In the absence of vaccination prophylaxis, 85 percent of infants born to HBeAg positive or high viraemia mothers will become chronic infected. Another route is called horizontal transmission. The HBV virus is transmitted by open wounds, blood transfusion, sharing unsterilized needles and unprotected sexual contact. HBV chronicity rate varies with the ages of patient at a time of acute HBV infection, ranging from 90 percent in a perinatal infection, 20-60 percent in children under five years old to below 5-10 in immuno competent adults. Worldwide, the majority of persons with chronic HBV infection are infected at birth or in early childhood. Data in Taiwan reported in 2009, also demonstrated that age at infection, a faster nature cause of HBV infection. Chronicity is the most important. Chronicity is most common following acute infection in neonates. In Taiwan, in era before universal HBV immunization, 2.5 million people above 15-20 percent of the adult population are HBV carriers. About 70-80 percent of hepatocellular carcinoma and liver cirrhosis are related to chronic HBV infection in adults. Both of them are the leading cause of deaths. Before the era of HBV vaccination program, professor Beasley already found that there are production efficacy [inaudible] HBIG plus HBV vaccines was higher than the group with no prophylaxis in preventing HBV infection of infants born to HBsAg and HBeAg double positive mothers. Persistent HBs antigenemia developed in only 5.7 percent of the total 159 infants receiving prophylaxis. But in 88 percent for the count throws in groups of HBIG plus vaccines, group ABC represented the subgroups with vaccination at different time schedules. We can find there was no difference in efficacy between these three schedules. On July 1st, 1984, amassed immunization program against HBV infection was launched in Taiwan. Two years later in 1986, professor [inaudible] conducted a study to assess the efficacy of this program. She found that the infants who were born to highly infectious carrier mothers and receive HBIG plus vaccines on schedule had a lower prevalence of HBsAg positivity than those who only received vaccines on schedule, but without HBIG. This confirmed the value of HBIG in preventing chronic HBV infection. Another study conducted in 1985 reported that there was no significant differences of protective efficacy in the groups with four doses of HBV vaccines plus one or two shots of HBIG. One dose of HBIG seems to be enough. On the other hand, if a mother was HBeAg negative HBV carrier, then the protective efficacy between HBIG plus HBV vaccines and HBV vaccines only is similar.
