Zhong Youjia, Kottaiswamy Amuthavalli, Ang Chen Xiang, Li Hui' En, Yap Gaik Chin, Tay Carina J X, Osman Nurul Elyana, Roslan Siti Namirah Binte, Tan Chee Wah, Yap Wee Chee, Ang Elizabeth Y, Chan Ng Pauline P L, Yap Hui Kim, Lu Liangjian, Aw Marion M, Karthik Sivaraman V, Quak Seng Hock, Quah Thuan Chong, Tham Elizabeth H, Shek Lynette P, Ooi Eng Eong
Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore, Singapore.
Program of Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore.
Front Immunol. 2024 Dec 17;15:1502598. doi: 10.3389/fimmu.2024.1502598. eCollection 2024.
In endemic COVID-19, immunocompromised children are vulnerable until vaccinated but the optimal primary vaccination regime and need for booster doses remains uncertain.
We recruited 19 immunocompromised children (post-solid organ transplantation, have autoimmune disease or were on current or recent chemotherapy for acute lymphoblastic leukemia), and followed them from the start of primary vaccination with BNT162b2 mRNA SARS-CoV-2 until 1-year post-vaccination. We investigated the quality of vaccine immunogenicity, and longevity of hybrid immunity, in comparison to healthy children.
Immunocompromised children failed to produce T cell and memory B cell (MBC) responses reaching thresholds of protection after 2 doses; a third dose however improved both responses. Initially robust hybrid immunity demonstrated significantly more decline in T cell and MBC responses in immunocompromised compared to healthy children, to levels below the protective threshold by month 12.
Immunocompromised children may benefit from a 3-dose primary vaccination regime, with yearly or twice-yearly booster doses for sustained immunity.
在新冠疫情流行地区，免疫功能低下的儿童在接种疫苗之前易受感染，但最佳的初次疫苗接种方案以及加强针的需求仍不确定。
我们招募了19名免疫功能低下的儿童（实体器官移植后、患有自身免疫性疾病或正在接受急性淋巴细胞白血病的当前或近期化疗），并从开始接种BNT162b2 mRNA新冠病毒疫苗起对他们进行随访，直至接种疫苗后1年。与健康儿童相比，我们调查了疫苗免疫原性的质量以及混合免疫的持久性。
免疫功能低下的儿童在接种2剂疫苗后未能产生达到保护阈值的T细胞和记忆B细胞（MBC）反应；然而，第三剂疫苗改善了这两种反应。最初强大的混合免疫显示，与健康儿童相比，免疫功能低下的儿童的T细胞和MBC反应下降更为显著，到第12个月时降至保护阈值以下。
免疫功能低下的儿童可能受益于3剂次的初次疫苗接种方案，并每年或每半年接种加强针以维持免疫力。
