S. Kalimuddin, C. Y. Tham, M. Qui, R. de Alwis, J. X. Sim, J. M. Lim, H. Tan, A. Syenina, S. Zhang, N. Le Bert, A. Tan, Y. S. Leong, Jia Xin Yee, E. Z. Ong, E. Ooi, A. Bertoletti, J. Low
Med, 2021
Background RNA vaccines against Covid-19 have demonstrated ∼95% efficacy in Phase III clinical trials. Although complete vaccination consisted of two-doses, the onset of protection for both licensed RNA vaccines was observed as early as 12 days after a single dose. The adaptive immune response that coincides with this onset of protection could represent the necessary elements of immunity against Covid-19. Methods Serological and T cell analysis was performed in a cohort of 20 healthcare workers after receiving the first dose of Pfizer/BioNTech BNT162b2 vaccine. The primary endpoint was the adaptive immune responses detectable at Days 7 and 10 after dosing. Results Spike-specific T cells and binding antibodies were detectable 10 days after the first dose of vaccine, in contrast to receptor-blocking and SARS-CoV-2 neutralising antibodies which were mostly undetectable at this early time-point. Conclusions Our findings suggest that early T cell and binding antibody responses, rather than either receptor-blocking or virus neutralizing activity, induced early protection against Covid-19. Funding The study was funded by a generous donation from The Hour Glass to support Covid-19 research.
Cited by 30 publications.
Field of study: Medicine