Comparative kinetics of SARS-CoV-2 anti-spike protein RBD IgGs and neutralizing antibodies in convalescent and naïve recipients of the BNT162b2 mRNA vaccine versus COVID-19 patients
Ioannis P. Trougakos, Evangelos Terpos, Christina Zirou, Aimilia D. Sklirou, Filia Apostolakou, Sentiljana Gumeni, Ioanna Charitaki, Eleni‐Dimitra Papanagnou, Tina Bagratuni, Christine‐Ivy Liacos, Andreas Scorilas, Eleni Korompoki, Ioannis Papassotiriou, Efstathios Kastritis, Meletios Α. Dimopoulos
Abstract
BACKGROUND: Coronavirus SARS-CoV-2, the causative agent of COVID-19, has caused a still evolving global pandemic. Given the worldwide vaccination campaign, the understanding of the vaccine-induced versus COVID-19-induced immunity will contribute to adjusting vaccine dosing strategies and speeding-up vaccination efforts. METHODS: Anti-spike-RBD IgGs and neutralizing antibodies (NAbs) titers were measured in BNT162b2 mRNA vaccinated participants (n = 250); we also investigated humoral and cellular immune responses in vaccinated individuals (n = 21) of this cohort 5 months post-vaccination and assayed NAbs levels in COVID-19 hospitalized patients (n = 60) with moderate or severe disease, as well as in COVID-19 recovered patients (n = 34). RESULTS: We found that one (boosting) dose of the BNT162b2 vaccine triggers robust immune (i.e., anti-spike-RBD IgGs and NAbs) responses in COVID-19 convalescent healthy recipients, while naïve recipients require both priming and boosting shots to acquire high antibody titers. Severe COVID-19 triggers an earlier and more intense (versus moderate disease) immune response in hospitalized patients; in all cases, however, antibody titers remain at high levels in COVID-19 recovered patients. Although virus infection promotes an earlier and more intense, versus priming vaccination, immune response, boosting vaccination induces antibody titers significantly higher and likely more durable versus COVID-19. In support, high anti-spike-RBD IgGs/NAbs titers along with spike (vaccine encoded antigen) specific T cell clones were found in the serum and peripheral blood mononuclear cells, respectively, of vaccinated individuals 5 months post-vaccination. CONCLUSIONS: These findings support vaccination efficacy, also suggesting that vaccination likely offers more protection than natural infection.