Persistence of Anti-HBs Antibody and Immunological Memory in Healthy Individuals Vaccinated with Hepatitis B Vaccine

Hepatitis B is an infectious illness caused by hepatitis B virus (HBV) which infects the liver of hominoidea, including humans, and causes an inflammation called hepatitis. Hepatitis B virus (HBV) infection is one of the major public health problems in the world (1). About 350 to 400 million people are chronically infected with hepatitis B worldwide. Originally known as ‘serum hepatitis’ (2), the disease has caused epidemics in parts of Asia and Africa, and it is endemic in China (3). Approximately 45% of the world population live in hyper-endemic areas where prevalence of hepatitis B surface antigen (HBsAg) is greater than 8%; 43% live in mid-endemic areas where HBsAg prevalence is 2% to 7%; and 12% live in hypoendemic areas where HBsAg prevalence is less than 2% (1,4). The acute illness causes liver inflammation, vomiting, jaundice and rarely, death. Chronic hepatitis B may eventually cause liver cirrhosis and liver cancera fatal disease with very poor response to current chemotherapy (5). However, the infection is preventable by vaccination (6). Vaccination against hepatitis B stimulates the body's immune defenses and protects most people. Effective control of HBV transmission in areas of high and intermediate endemicity would not be possible without vaccination of the vulnerable group of the population (7). The WHO strategy for effective control of HBV infection and its sequel is mass vaccination of neonates and children within the framework of Expanded Program on Immunization (EPI) (8). It has been recommended that all countries integrate hepatitis B vaccine into national immunization by the year 1997 (8). Hepatitis B virus (HBV) infection is one of the major public health problems in the world. It is estimated that there are three hundred million HBV carriers and around one million deaths annually due to HBV infection worldwide. Vaccination is considered to be the best solution to this problem. The present study was conducted to investigate the efficacy of the vaccine administered against hepatitis B and to reveal the immunological memory against the vaccine. Samples were taken from both male (74 individuals) and female (37 individuals) from different age groups ranging from three to sixty three years. Among the population studied, both good (63.06%) and hypo (36.94%) responders were found. All the individuals (100%) showed a satisfactory result having an anti-HBs antibody titer above the protective level (≥ 10 IU/L). Received 19 February 2011/Accepted 25 April 2011 Persistence of Anti-HBs Antibody and Immunological Memory in Healthy Individuals Vaccinated with Hepatitis B Vaccine