Salama Iman I, Sami Samia M, Elserougy Safaa M, Emam Hanaa M, Salama Somaia I, Elhariri Hazem M, Hemeda Samia A, Hassanain Amal I, Abdel Mohsen Aida M, Fouad Walaa A, El Etreby Lobna A, Said Zeinab N
Community Medicine Research Department, National Research Center, Cairo, Egypt.
Child Health Department, National Research Center, Cairo, Egypt.
Oman Med J. 2020 Sep 30;35(5):e175. doi: 10.5001/omj.2020.117. eCollection 2020 Sep.
We sought to assess the prevalence of hepatitis B virus (HBV) seroprotection among vaccinated children in the Assiut governorate, Egypt, and assess a booster dose immune memory response among non-seroprotected children.
Using a multistage cluster sample, 566 children were recruited from three clusters: one urban and two rural. Children were aged from nine months to 16 years old. All participants received the full three doses of the compulsory HBV vaccine during infancy. Serum hepatitis B surface antigen (HBsAg), total anti-hepatitis B core (anti-HBc) antibodies, and quantitative detection of anti-HBs were measured using enzyme-linked immunosorbent assay. Repeatedly positive samples for HBsAg/anti-HBc were submitted for quantitative HBV DNA detection using real-time polymerase chain reaction. Non-seroprotective participants (anti-HBs < 10 IU/L) were given a booster dose of HBV vaccine. Two weeks later, a blood sample was taken from each child to assess an anamnestic response.
The seroprotection rate was 53.2%, and only two children had HBV breakthrough infection (0.4%) with positive serum anti-HBc and HBV DNA. Age was the only significant predictor for non-seroprotection with an adjusted odds ratio (OR) of 3.2, 9.4, and 9.9 among children aged 5-10, 11-15, and > 15 years, respectively, compared to younger children ( < 0.001). About 85% of non-seroprotected children developed an anamnestic response after receiving the booster dose, and 84.3% of responders had a good response ( 100 IU/L). Undetectable pre-booster titer was found to be the only risk factor for non-response to booster with OR = 3.2 ( < 0.010). About 95.7% of children who were not responding to booster dose developed immune response after receiving the three doses of HBV vaccine.
Older age of children was the only significant predictor for HBV non-seroprotection. High anamnestic response rate signifies the presence of immune memory with long-term protection despite the waning of anti-HBs over time. However, some children with pre-booster undetectable anti-HBs titers may be unable to develop anamnestic response, and a second vaccination series might be necessary for HBV protection for these children.
我们试图评估埃及阿斯尤特省接种疫苗儿童中乙肝病毒（HBV）血清保护的流行情况，并评估未获得血清保护的儿童接种加强剂量疫苗后的免疫记忆反应。
采用多阶段整群抽样方法，从三个群组中招募了566名儿童：一个城市群组和两个农村群组。儿童年龄在9个月至16岁之间。所有参与者在婴儿期均接受了完整的三剂强制性乙肝疫苗接种。采用酶联免疫吸附测定法检测血清乙肝表面抗原（HBsAg）、总抗乙肝核心（抗-HBc）抗体以及抗-HBs的定量检测。对HBsAg/抗-HBc反复呈阳性的样本，采用实时聚合酶链反应进行HBV DNA定量检测。对未获得血清保护的参与者（抗-HBs<10 IU/L）给予一剂乙肝疫苗加强针。两周后，从每个儿童采集血样以评估回忆反应。
血清保护率为53.2%，仅有两名儿童发生HBV突破性感染（0.4%），血清抗-HBc和HBV DNA呈阳性。年龄是未获得血清保护的唯一显著预测因素，与年龄较小的儿童（<0.001）相比，5-10岁、11-15岁和>15岁儿童的调整优势比（OR）分别为3.2、9.4和9.9。约85%未获得血清保护的儿童在接种加强剂量疫苗后出现回忆反应，84.3%的反应者反应良好（≥100 IU/L）。加强针前检测不到滴度是对加强针无反应的唯一危险因素，OR=3.2（<0.010）。约95.7%对加强针无反应的儿童在接种三剂乙肝疫苗后产生了免疫反应。
儿童年龄较大是未获得HBV血清保护的唯一显著预测因素。高回忆反应率表明存在免疫记忆，尽管抗-HBs随时间下降，但仍具有长期保护作用。然而，一些加强针前抗-HBs滴度检测不到的儿童可能无法产生回忆反应，对于这些儿童，可能需要进行第二系列疫苗接种以保护其免受HBV感染。
