A Study to Test the Efficacy of the HBV Vaccine and to Look at the Prevalence of HBV Infection

The prevalence of Hepatitis B core antigen in the Thai population is about 70 %, no data of isolated Hepatitis B core antigen is reported. Hepatitis B core antigen is observed in 10%-20% of individuals from low endemic areas of HBV infection. However, this prevalence of isolated antiHBc would be higher in endemic area of HBV infection. There is conflicting data of occult HBV infection in HIV infected patients. In Thailand, perinatal transmission is the main route of transmission which is different from developed countries. Therefore, isolated antiHBc in Thai people has longer duration than low prevalence regions. Moreover, HBV genotype C and B is common in this region. If the HBV vaccination could eliminate an occult HBV infection in these individuals, the liver related mortality might be reduced. The prevalence and clinical importance of isolated antiHBc in Thai have not been investigated yet. There is also limited data of HBV vaccine response in this setting.