| Objectives1. To study the immune status of children between5to16years old who received Hepatitis B(HepB)primary vaccination in infancy, and to evaluate the long-term immunological effect ofHepB.2. To study the immunogenicity and influencing factors of HepB booster vaccination forchildren between5and16.3. To evaluate the immunological effect of different HepB booster vaccination strategies, soas to provide scientific support for formulating proper booster vaccination strategy.MethodsResearch samples were selected from6cities in Zhejiang Province based on local level ofHepB endemicity: Yuhuan and Xianju [areas of high Hepatitis B virus (HBV) endemicity],Longquan and Qingyuan (areas of intermediate HBV endemicity), Kaihua and Changshan (areasof low HBV endemicity). Two towns were then selected from each of these cities.From localschools, children between5and16, who received HepB primary vaccination during infancy but nobooster vaccination, were selected through cluster sampling. Questionnaire surveys were thenconducted among these children, so as to collect information including their name, gender, birthdate, home address and past record of receiving HepB vaccination. In the next step,3ml of venousblood was collected from each of these children, to further test HBV surface antigen (HBsAg),antibodies to HBV surface antigen (anti-HBs) and antibodies to HBV core antigen (anti-HBc).Only those with all three negative indicators could enter the pool of final samples.Four differentHepB were then injected into these children on a0-1-6month schedule. One month after theinjection of the first dose,3ml of venous blood was collected from each of these children again, totest anti-HBs. The same was done after the third doze had been injected for1month. Finally, viachemical luminescence method, all serological indicators went through quantitative detection. Alldata was input twicely by EPI data3.2software, and was then analyzed by SPSS18.0.Results1. Long-term immunological effect of HepB primary vaccinationThis study has surveyed and collected blood samples from7,454children who receivedprimary vaccination.The total positive rate of HBsAg, anti-HBs and anti-HBc were1.19%,43.91% and4.28%. The anti-HBs positive rate was lower in areas of low HBV endemicity than in areas ofintermediate and high HBV endemicity. Along with the growth of age, these children’s averageanti-HBs positive rates gradually declined from59.24%to37.39%,and the trend was significantdifference(P﹤0.05).The Geometric Mean Titer (GMT) of7,117children with both negativeHBsAg and anti-HBc was4.75mIU/ml. Changes in factors like age and local HBV endemicity didcause significant differences in the level of GMT.2. Effect of HepB booster vaccination3,824children received the first dose of four different HepB, namely HepB vaccine madefrom recombinant Deoxyribonucleic Acid（DNA）Techniques in Yeast (HepB-Y), HepB vaccinemade from recombinant DNA Techniques in Hansenula Polymorpha Yeast (HepB-HPY), HepBvaccine made from recombinant DNA Techniques in Chinese Hanlster Ovary（CHO）Cell(HepB-CHO), and Hepatitis A and Hepatitis B combined vaccine.Testing results showed that therelevant anti-HBs positive rates were89.91%,92.92%,90.80%and86.31%. The GMTs were247.35mIU/ml,776.68mIU/ml,299.36mIU/ml and168.97mIU/ml respectively, and there weresignificant differences (P﹤0.05). Anti-HBs positive rates and GMTs were lower in areas of lowHBV endemicity than areas of high HBV endemicity. Besides, along with the growth of age, bothanti-HBs positive rates and GMTs declined.After all three doses of the four different HepB, anti-HBs positive rates were respectively99.50%,99.66%,99.05%and99.00%, but there was nosignificant difference (P﹥0.05). GMTs were650.98mIU/ml,2493.98mIU/ml,580.17mIU/ml and443.84mIU/ml respectively, and the difference was significant (P﹤0.05). Changes in local level ofHBV endemicity didn’t cause significant differences in anti-HBs positive rates and GMTs (P﹥0.05). Anti-HBs positive rates of children from each age group were higher than98%, but GMTswere higher among children at younger ages. After the first dose and the third dose of HepB, anti-HBs positive rates were90.40%and99.35%respectively, while GMTs were344.82mIU/ml and894.58mIU/ml. Both of them were significant differences (P﹤0.05).Conclusions1. Children who received HepB primary vaccination in infancy can lose their immunememory after5to16years. HepB booster vaccination is needed for children with negative anti-HBs.2. The four afore-mentioned HepB, HepB-Y, HepB-HPY, HepB-CHO as well as Hepatitis Aand Hepatitis B combined vaccine, all have excellent immunological effects of booster vaccination.3. The immunological effects gradually decline with the prolongation of time after primaryvaccination. The effects of3doses are better than1dose. |
PDF Full Text Request