Initial SARS-CoV-2 vaccination response can predict booster response for BNT162b2 but not for AZD1222

Objective: To determine whether severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibody levels after the first dose of vaccine can predict the final antibody response, and whether this is dependent on the vaccine type. Methods: Sixty-nine recipients of BNT162b2 (Pfizer/BioNTech) and 55 recipients of AZD1222 (AstraZeneca), without previous infection or immunosuppressive medication, were included in this study. Antibody levels were quantified 3 weeks after the first dose [directly before boostering in the case of AZD1222 (11 weeks after the first dose)] and 3 weeks after the second dose using the Roche Elecsys SARS-CoV-2 S total antibody assay. Results: Median pre-booster {BNT162b2: 80.6 [interquartile range (IQR) 25.5-167.0] binding antibody units (BAU)/mL; AZD1222: 56.4 (IQR 36.4-104.8) BAU/mL; not significant} and post-booster [BNT162b2: 2092.0 (IQR 1216.3-4431.8) BAU/mL; AZD1222: 957.0 (IQR 6 84.5-16 84.8) BAU/mL; P < 0.0 0 01] levels correlated well in the recipients of BNT162b2 ( rho= 0.53) but not in the recipients of AZD1222. Moreover, antibody levels after the first dose of BNT162b2 correlated inversely with age ( rho= -0.33, P = 0.013), whereas a positive correlation with age was observed after the second dose in recipients of AZD1222 ( rho= 0.26, P = 0.030). Conclusions: The results of this study suggest that antibody levels quantified by the Roche Elecsys SARS-CoV-2 S assay before the booster shot could infer post-booster responses to BNT162b2, but not to AZ1222. In addition, this study found a vaccine-dependent effect on antibody responses, where age seems to play an ambivalent role. (c) 2021 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Automated summary

The study suggests that antibody levels quantified before the booster shot with the Roche Elecsys SARS-CoV-2 S assay may predict post-booster responses to BNT162b2, but not to AZD1222. There is a vaccine-dependent effect on antibody responses, with age playing an ambivalent role in the immune response.