Immunogenicity and reactogenicity of SARS-CoV-2 vaccines BNT162b2 and CoronaVac in healthy adolescents
Jaime S. Rosa Duque, Xiwei Wang, Daniel Leung, Samuel M. S. Cheng, Carolyn A. Cohen, Xiaofeng Mu, Asmaa Hachim, Yanmei Zhang, Sau Man Chan, Sara Chaothai, Kelvin K. H. Kwan, Kaimin Chan, John K. C. Li, Leo L. H. Luk, Leo C. H. Tsang, Wilfred Hing Sang Wong, Cheuk Hei Cheang, Timothy Hung, Jennifer H. Y. Lam, Gilbert T. Chua, Winnie W. Y. Tso, Patrick Ip, Masashi Mori, Niloufar Kavian, Wing Leung, Sophie A. Valkenburg, Malik Peiris, Wenwei Tu, YL Lau
Abstract
We present an interim analysis of a registered clinical study (NCT04800133) to establish immunobridging with various antibody and cellular immunity markers and to compare the immunogenicity and reactogenicity of 2-dose BNT162b2 and CoronaVac in healthy adolescents as primary objectives. One-dose BNT162b2, recommended in some localities for risk reduction of myocarditis, is also assessed. Antibodies and T cell immune responses are non-inferior or similar in adolescents receiving 2 doses of BNT162b2 (BB, N = 116) and CoronaVac (CC, N = 123) versus adults after 2 doses of the same vaccine (BB, N = 147; CC, N = 141) but not in adolescents after 1-dose BNT162b2 (B, N = 116). CC induces SARS-CoV-2 N and N C-terminal domain seropositivity in a higher proportion of adolescents than adults. Adverse reactions are mostly mild for both vaccines and more frequent for BNT162b2. We find higher S, neutralising, avidity and Fc receptor-binding antibody responses in adolescents receiving BB than CC, and a similar induction of strong S-specific T cells by the 2 vaccines, in addition to N- and M-specific T cells induced by CoronaVac but not BNT162b2, possibly implying differential durability and cross-variant protection by BNT162b2 and CoronaVac, the 2 most used SARS-CoV-2 vaccines worldwide. Our results support the use of both vaccines in adolescents.