Salama Iman, Sami Samia, Saleh Rehan, Mohsen Amira, Elserougy Safaa, Emam Hanaa, Said Zeinab
Department of Community Medicine Research, National Research Centre, Egypt.
Department of Child Health, National Research Centre, Egypt.
J Egypt Public Health Assoc. 2017 Jun 1;92(2):77-85. doi: 10.21608/epx.2018.8945.
Although Egypt had adopted implementation of routine infant hepatitis B virus (HBV) vaccination in 1992, its effectiveness is not evaluated on a national scale. Assessment of early and long-term seroprotection after compulsory vaccination is an important measure for monitoring the success of the vaccination program.
The aim of this study was to assess HBV seroprotection and immune memory in children and adolescents who were vaccinated during infancy in Cairo Governorate.
The study was carried out in two phases. The first phase was a cross-sectional study carried out in five districts in Cairo Governorate, recruiting 819 children in the age range of 9 months to 16 years. All children had received full doses of the compulsory HBV vaccination. Serum samples were taken from each child and assessed for antibody against hepatitis B virus surface antigen (anti-HBs) titer; total antibodies against HBV core antigen, and HBV surface antigen. HBV DNA was investigated by real-time PCR for those who were HBV core antigen or HBV surface antigen positive. In the second phase, nonseroprotected children (anti-HBs <10 IU/I) received HBV booster dose. AntiHBs titer was reassessed after 4 weeks to identify anamnestic response. Individuals showing antibody concentrations ofless than 10 IU/l were then given an additional complete course of vaccination.
Four out of 819 children had HBV breakthrough infection. The seroprotection rate was 60.7%, and was significantly higher among children aged less than 5 years compared to the older age groups and among boys compared to girls. Multivariate logistic analysis showed age as the only independent predictor of low anti-HBs titer. About 95% of nonseroprotected children developed anamnestic response postbooster. Anti-HBs geometric mean titer (GMT) increased significantly from pre-booster (13.8±16.9IU/L) compared to post-booster (307±6.0IU/L, P<0.001). Anti-HBs GMT was significantly higher among children with prebooster anti-HBs level ≥1 IU/l (424.9±4.4 IU/l) compared to children with undetectable level (178.3±8.3).
Despite waning of anti-HBs over time, long-term protection still exists. The high anamnestic response rate signifies the existence of immune memory and giving a booster dose is not recommended. However, we suggest that prolonged follow up and surveillance of vaccinees immunized at an early age should be continued.
尽管埃及于1992年开始实施常规婴儿乙型肝炎病毒（HBV）疫苗接种，但其有效性尚未在全国范围内进行评估。评估强制接种疫苗后的早期和长期血清保护是监测疫苗接种计划成功与否的一项重要措施。
本研究的目的是评估开罗省婴儿期接种疫苗的儿童和青少年的HBV血清保护和免疫记忆情况。
本研究分两个阶段进行。第一阶段是在开罗省的五个区开展的横断面研究，招募了819名年龄在9个月至16岁之间的儿童。所有儿童均已接种了完整剂量的强制性HBV疫苗。采集每个儿童的血清样本，评估乙型肝炎病毒表面抗原抗体（抗-HBs）滴度、抗HBV核心抗原总抗体以及HBV表面抗原。对HBV核心抗原或HBV表面抗原呈阳性的儿童通过实时PCR检测HBV DNA。在第二阶段，对未产生血清保护的儿童（抗-HBs<10 IU/I）接种HBV加强剂量疫苗。4周后重新评估抗HBs滴度以确定回忆反应。然后对抗体浓度低于10 IU/l的个体再接种一个完整疗程的疫苗。
819名儿童中有4名发生HBV突破性感染。血清保护率为60.7%，5岁以下儿童的血清保护率显著高于年龄较大的儿童组，男孩的血清保护率显著高于女孩。多因素逻辑分析显示年龄是抗-HBs滴度低的唯一独立预测因素。约95%未产生血清保护的儿童在接种加强剂量疫苗后出现回忆反应。与接种加强剂量疫苗前（13.8±16.9IU/L）相比，抗-HBs几何平均滴度（GMT）在接种加强剂量疫苗后显著升高（307±6.0IU/L，P<0.001）。接种加强剂量疫苗前抗-HBs水平≥1 IU/l的儿童的抗-HBs GMT显著高于检测不到抗-HBs水平的儿童（424.9±4.4 IU/l比178.3±8.3）。
尽管抗-HBs水平会随时间下降，但长期保护仍然存在。高回忆反应率表明存在免疫记忆，不建议接种加强剂量疫苗。然而，我们建议继续对早期接种疫苗者进行长期随访和监测。
