One method to determine the long-term protection provided by hepatitis B vaccine against HBV infection is to estimate the cumulative incidence of chronic carrier status and breakthrough infection of previously vaccinated individuals in different periods. Up to now, no international standard suggests that hepatitis B vaccine should be used as a routine immunization program. However, it is an important issue to discuss the immune protection of healthy children with negative hepatitis B surface antibody and the duration of this protection in the future. Therefore, this study aims to evaluate the existence of immune protection of healthy children with negative hepatitis B surface antibody, find a method to evaluate the immune protection induced by hepatitis B vaccine.~The main content of the study: To recruit healthy children. Children lacking HBsAb were selected for immune memory test and receive a Hep B booster. The results of Antibody positive group and antibody negative group were compared and analyzed. To find out the most suitable method for evaluating immune protection.
Worldwide, hepatitis B virus (HBV) infection is a major cause of acute hepatitis,and chronic infection with HBV often leads to chronic hepatitis, liver cirrhosis,and hepatocellular carcinoma. So far, the most effective way to prevent HBV infection in susceptible population is to inject hepatitis B vaccine. However, long-term protection against hepatitis B virus (HBV) after vaccination remains widely debated. This study aims to evaluate the existence of immune protection in healthy children with negative hepatitis B surface antibody and find a method to evaluate the immune protection induced by hepatitis B vaccine.