Infectious Disease Service, Department of Paediatrics, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore, 229899, Singapore.
Duke-National University of Singapore Medical School, Singapore, Singapore.
Sci Rep. 2023 Oct 13;13(1):17337. doi: 10.1038/s41598-023-44565-x.
There is little information on BNT162b2 vaccine-induced variant-specific immunogenicity, safety data and dynamics of breakthrough infections in pediatric populations. We addressed these questions using a prospective two dose BNT162b2 (10 mcg) vaccination cohort study of healthy children 5-11 years in Singapore. Follow up included blood samples at scheduled visits, daily vaccination symptom diary and confirmation of SARS-CoV-2 infection. Surrogate virus neutralization test (sVNT) and spike-specific T cell responses against SARS-CoV-2 variants were performed. The mean age of 127 participants was 8.27 years (SD 1.95) and 51.2% were males. The median sVNT level against original variant after 1 dose and 2 dose vaccination was 61.4% and 95.1% respectively (p < 0.0001). Neutralizing antibodies against the Omicron variant was the lowest, median 22.4% (IQR 16.5-30.8). However, T cell IFN-γ cytokine response against Omicron variant was high and remained so about 4 months after vaccination. Fever rate increased significantly from 4% (dose 1) to 11.5% (dose 2). The risk of Omicron breakthrough infection decreased by 7.8% for every 1% increase in sVNT inhibition level measured after dose 2 vaccination. BNT162b2 vaccines were safe, induced good T cell responses but poor neutralizing antibodies against Omicron in children. Low neutralizing antibody levels post-vaccination was predictive of subsequent breakthrough infection.
关于 BNT162b2 疫苗引起的针对变异株的免疫原性、安全性数据和突破性感染的动力学，相关信息有限。我们在新加坡进行了一项前瞻性的、两剂 BNT162b2（10μg）接种研究，该研究纳入了 5-11 岁健康儿童。随访包括定期就诊时的血液样本、每日接种症状日记和 SARS-CoV-2 感染的确认。进行了替代病毒中和试验（sVNT）和针对 SARS-CoV-2 变异株的刺突特异性 T 细胞反应检测。127 名参与者的平均年龄为 8.27 岁（标准差 1.95），51.2%为男性。一剂和两剂接种后，针对原始变异株的 sVNT 水平中位数分别为 61.4%和 95.1%（p<0.0001）。针对奥密克戎变异株的中和抗体最低，中位数为 22.4%（IQR 16.5-30.8）。然而，针对奥密克戎变异株的 T 细胞 IFN-γ细胞因子反应较高，并且在接种后约 4 个月仍保持较高水平。发热率从第 1 剂的 4%显著增加至第 2 剂的 11.5%。第 2 剂接种后，sVNT 抑制水平每增加 1%，奥密克戎突破性感染的风险降低 7.8%。BNT162b2 疫苗安全，可诱导良好的 T 细胞反应，但在儿童中针对奥密克戎的中和抗体水平较低。接种后中和抗体水平较低可预测随后的突破性感染。
