AUTHOR=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 

TITLE=Reduced durability of hybrid immunity to SARS-CoV-2 in immunocompromised children

JOURNAL=Frontiers in Immunology

VOLUME=Volume 15 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1502598

DOI=10.3389/fimmu.2024.1502598

ISSN=1664-3224

ABSTRACT=BackgroundIn endemic COVID-19, immunocompromised children are vulnerable until vaccinated but the optimal primary vaccination regime and need for booster doses remains uncertain.MethodsWe 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.ResultsImmunocompromised 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.DiscussionImmunocompromised children may benefit from a 3-dose primary vaccination regime, with yearly or twice-yearly booster doses for sustained immunity.