Comparative Characterization of Human Antibody Response Induced by BNT162b2 Vaccination vs. SARS-CoV-2 Wild-Type Infection

Abstract

Humoral immunity after SARS-CoV-2 immunization or natural infection is thought to be evanescent. In our study, we aimed to longitudinally characterize the kinetics of antibody titers after dual BNT162b2 immunization or wild-type infection. Vaccinated and recovered individuals displayed distinct antibody kinetics, as convalescents had detectable RBD-, S1-specific, and neutralizing IgG antibody titers two weeks post-infection that gradually increased longitudinally, while RBD-, S1-specific, and neutralizing IgG were detected in vaccinees after the first dose, increased significantly 3 weeks post the second dose and decreased significantly 4–5 months thereafter. Neutralizing IgG was significantly higher initially in convalescent individuals; however, vaccines displayed significantly higher neutralizing antibodies 4–5 months post the second dose. In both groups, there was a strong negative association between elapsed time and antibody levels. The avidity of anti-RBD antibody titers increased significantly in patients longitudinally, while in vaccinees initially increased, with subsequent decrease, remaining however higher than antibody avidity of recovered individuals at all time-points. Anti-RBD antibodies were strongly correlated with neutralizing and anti-S1 antibodies in both groups at all time-points. This study facilitates our further understanding of immune response to SARS-CoV-2 and vaccines.

Serum antibody levels to SARS-CoV-2 receptor-binding domain (RBD) in convalescent patients and vaccinated individuals of northern Nevada

“…As shown in Figs 1 and 2 , there was a greater anti-RBD response in the vaccinated group versus the naturally infected group, despite a longer timeframe between immunization and sample collection. The data from this study supports both greater overall titer induction and longer duration from vaccination compared to natural infection, and confirms similar findings in other studies [ 15 – 17 ]. Furthermore, titers to the Wu-Hu-1 RBD confer some cross-reactive antibodies to the RBD of emerging viral isolates.…”

Retained avidity despite reduced cross-binding and cross-neutralizing antibody levels to Omicron after SARS-COV-2 wild-type infection or mRNA double vaccination

“…Study groups also differed in age, yet multivariable analysis revealed no confounding impact of said age differences between study cohorts on avidity results, a finding supported by a previous study from our group that showed no difference in avidity maturation across age (33). We consider higher avidity in vaccinated individuals likely to reflect a possible benefit of repeated exposure to the antigen (28,34,35); a perception also in line with our finding that vaccination was shown to be a predictor of avidity maturation toward the new variant, independent of antibody titer.…”

“…Selected samples from the vaccinated cohort were OM IgG antibody concentration-matched to the convalescent samples to prevent any influence of antibody level on avidity determination and guarantee comparability of the avidity maturation progress, because the antibody concentrations have been shown to affect avidity outcomes (24). Contrary to our findings of higher antibody concentrations toward the WT S1 protein [GM (95% CI): 28 1C, D). This finding remained significant in a multivariable regression analysis that adjusted for age, sex, and days after contact (Supplementary Tables 2, 3).…”

“…Our results of an overall 75% of WT positive individuals fits well into research showing considerable IgG antibody waning after an initial peak within the first 3 months after antigen contact. Data on antibody dynamics have further shown initially high IgG levels (especially after vaccination) to decay rapidly, eventually plateauing into stable levels, persisting up to 1 year and beyond (19,(28)(29)(30)(31)(32).…”

Evolution of antibody titers after two doses of mRNA Pfizer-BioNTech vaccine and effect of the third dose in nursing home residents

“…Antibody levels showed high variability in all investigated groups. Considering that the exact date of infection of each PI resident was not available (in most cases it was only recorded as "first wave"), it cannot be ruled out that the time elapsed from infection to serological analysis may influence in the different antibody titers found in this cohort as mentioned by other authors [22].…”