The immune response to SARS-CoV-2 in COVID-19 as a recall response susceptible to immune imprinting: A prospective cohort study.

Unlabelled: The antibody response to SARS-CoV-2 does not follow the immunoglobulin isotype pattern of primary responses, conflicting with the current interpretation of COVID-19.

Methods: Prospective cohort study of 191 SARS-CoV-2 infection cases and 44 controls from the second wave of COVID-19. The study stratified patients by severity and analyzed the trajectories of SARS-CoV-2 antibodies and multiple immune variables.

Results: Isotype-specific antibody time course profiles to SARS-CoV-2 revealed a pattern of recall response in 94.2 % of cases. The time course profiles of plasmablasts, B cells, cTfh high-resolution subsets, and cytokines indicated a secondary response. The transcriptomic data showed that this cohort is strictly comparable to contemporary cohorts.

Conclusions: In most cases, the immune response to SARS-CoV-2 is a recall response. This constitutes a favorable scenario for most COVID-19 cases to be subjected to immune imprinting by endemic coronavirus, which, in turn, can influence the immune response to SARS-CoV-2.