Efficacy of Hepatitis B Vaccine Boosters Among Neonatally Vaccinated Children in Chongqing

Hepatitis B virus (HBV) infection is a major public health problem around the world. More than 2 billion people have been infected with HBV. Although the World Health Organization (WHO) has incorporated hepatitis B vaccination into routine immunization programs for infants and adolescents since 1986 to reduce the incidence of chronic liver diseases, liver cirrhosis and hepatocellular carcinoma associated with hepatitis B virus, there are still more than 400 million chronic carriers. Although it is currently recognized that the most effective way to prevent HBV infection in susceptible population is to inject hepatitis B vaccine, the protective effect of the neonatally vaccinated children weakened as time goes on, which involves the question of the need of boosters. However, there are still some problems concerning hepatitis B vaccine boosters for healthy children. In China, there has not been a standardized directory to guide hepatitis B vaccine booster. Scholars have great controversy on the necessity, age, dosage and other aspects of hepatitis B vaccine booster. Researchers conducted an investigation on the Anti-HBs level of 93,326 Chinese children aged 1 - 16 who completed basic immunization. The results showed that the proportion of HBsAb positive in children aged 1 - 8 years old decreased dramatically, with 8 - year - old children having the lowest proportion of protective antibody. Therefore, this study is intended to explore the protective effect of hepatitis B vaccine on the body and the effect of multiple vaccines. This study will recruit some healthy children with anti-HBs at a low level (titer \<10mIU/mL and \[10,100) mIU/mL) in Chongqing and conduct selective re-vaccination according to the results of the first detection of hepatitis B surface markers in healthy children. According to the changes of immune status after booster, the efficacy of hepatitis B vaccine boosters was comprehensively evaluated.