The hepatitis A takes the children as the main objects to invade, which can be found in the rural and urban infant institutions as the epidemic. To administrate the hepatitis A vaccine on children is the effective measure to prevent form the infection of the hepatitis A. at present, the domestic activated hepatitis A vaccine and imported inactivated hepatitis A vaccine are being applied in China. In September 1998, while we conducted the second phase of clinic study on the domestic inactivated hepatitis A vaccine, the study on immunogenicity and the safety of the inactivated hepatitis A applied on the children of HBsAg carriers were performed as the follows,

1.        Materials and Methods

1.1    The inactivated hepatitis A vaccine was provided by Tangshan Yi’an Bioengineering Co., Ltd., containing 1000U or 500U viral antigen in each dose, with the ratified number of 971201.

1.2    Vaccinated objects: children aged 1-10 years, anti-HAV (-), ALT<40U.

1.3    Vaccination method: injection at deltoid muscle of the upper arm, 6-month interval between the first dose and the second dose (0.6 schedule).

1.4    Blood sample: 3 ml of venous blood was taken in 1 month after the primary immunization, and 1 and 6 months after the booster immunization, to asepsis separate the serum, kept at -20℃ for test.

1.5    Anti-HAV test

1.5.1    Standard Hepatitis A antibody: it was provided by the WHO with the ratified number of 990201, and the concentration at 98.6U/ml.

1.5.2    The qualitative test of hepatitis A antibody: the ELISA agent was used, provided by the Abbott Company, with the ratified number of 5477 RM100, and the competitive restraint rate > 50% was positive.

1.5.3    HA antibody level test: the hepatitis A antibody agent box calibrated by standard HA antibody was used to test with the ratified number of 990528, and the sensitivity of 106-127 mIU/ml.

1.6    HBV test: the agent box (ELISA) was purchased from Shanghai Industry Kehua Bioengineering Technology Company, with the ratified number of 980605 and 980702.

1.7    ALT test: Innovated Laishi Method, the reference value < 40U, produced by Beijing Chemical Plant, with the ratified number of 980820.

1.8    HBsAg carrier children       there are 10 children carrying both positive HBsAg and positive HBeAg.

1.9    Side effects observation: the body temperature should be measured after 0 (instant), 8, 24, 48 and 72 hours after each dose was vaccinated, to observe the local effects and the systematic effects, the abnormality can be judged according to the referred document ^[4].

2          Results

2.1    Observe the liver function: after the inactivated hepatitis A vaccine was administrated, the positive HBsAg and negative HBeAg children were normal for ALT. Within 72 hours after vaccination, there were no significant side effects.

2.2    Hepatitis A antibody level: as for the HBsAg carriers and healthy children, in one month after the primary immunization and in 1 and 6 months after the booster immunization, the levels of their antibodies were raised significantly (See Table 1). Under the different dosages, compared the HBsAg carriers and the healthy children, the average P values of them were more than 0.05, without significant difference.

Table 1       The anti-HAV level at injection (geometric mean titer of anti-HAV mIU/ml)

3         Discussions

The inactivated hepatitis A has been brought into use in abroad, and the comparative experiments at random ^[5] have been done in children and adults. The antibody positive seroconversion rate can reach to 100% after 2 or 3 doses are vaccinated, with high anti-HAV level. The inactivated hepatitis A vaccine has ever been used together with the vaccine of the yellow fever, but there is no interference each other ^[6]. However, the antibody level report on HBsAg carrying children after applied by inactivated hepatitis A vaccine hasn’t been found till now. Aiming at 10 HBsAg carrying children, the safety and the immunogenicity of the inactivated hepatitis A vaccine were compared. Although the compared personnel were not many, it is making great contribution on the real application of the inactivated hepatitis A vaccine in China. The significant local and systematic effects were not found in 72 hours after the HBsAg carrying children were administrated the inactivated hepatitis A vaccine, and the ALT was normal, which proved that the vaccine was safe to the children. The HBsAg had no interference on the vaccination response of the inactivated HAV vaccine. The antibody levels of the HBsAg carrying children in 1 month and 6 months after the booster immunization had no significant differences with those of the healthy children. Therefore, the forgoing study showed that, Both HBsAg carrying children and the healthy children had the good vaccination responses on the inactivated hepatitis A vaccine.

Thanks to Mr. Cui Lianyun, and Mr. Li Haijun of Pingshan County Epidemic Prevention Station for their participation.

References

1          Wang Liwei, Jia Yiping, Zhang Henxing, and Associates, Investigation on hepatitis A prevalence in a village, Chinese Journal of  Epidemiology Magazine, 1987, 3: 184.

2          Xu Dezhong, Zhuo Wenli, Li Yuanjing, and Associates, The Epidemiological Investigation on HAV in Infant Institutions, China Medicine Magazine, 1985, 3: 148. 

3          The Epidemiological Observation on Long-term Effects of the Activated Hepatitis A Vaccine (H2 strain) Applied on Children, China Epidemiology Magazine, 2000, 4: 316.

4          Ze Wenyuan, Side Effects of the Vaccination and the Treatment Principles, Planning Immunology edited by Ze Wenyuan, Shanghai, Science and Technology Works Press, 1997, 41-52.

5.    Richtmona R. Chaves RI, Moadones JS, et al. Immunoenicity and efficarr of a killed   

        hepatitis A vaccine is day care ceater children J Med Virol 1996, 48:148-150

6.    Gil A  Geosales A careeo JR, et al. The interference of yellow fever vaccine with the

       immune response to a signle-down inactivated hepatitis A vaccine ( 1440 EIU) a   

      control study on adults. Vaccine 1996 14; 1028-1030.