210-Day Kinetics of Total, IgG, and Neutralizing Spike Antibodies across a Course of 3 Doses of BNT162b2 mRNA Vaccine

Chin Shern Lau; May Lin Helen Oh; Soon Kieng Phua; Ya-Li Liang; Tar Choon Aw

doi:10.3390/vaccines10101703

210-Day Kinetics of Total, IgG, and Neutralizing Spike Antibodies across a Course of 3 Doses of BNT162b2 mRNA Vaccine

Vaccines (Basel). 2022 Oct 12;10(10):1703. doi: 10.3390/vaccines10101703.

Authors

Chin Shern Lau¹, May Lin Helen Oh², Soon Kieng Phua¹, Ya-Li Liang¹, Tar Choon Aw^{1

3

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Affiliations

¹ Department of Laboratory Medicine, Changi General Hospital, 2 Simei Street 3, Singapore 529889, Singapore.
² Department of Infectious Diseases, Changi General Hospital, Singapore 529889, Singapore.
³ Department of Medicine, National University of Singapore, Singapore 117599, Singapore.
⁴ Academic Pathology Program, Duke-NUS Graduate Medical School, Singapore 169857, Singapore.

Abstract

Introduction: We tested the total spike antibody (S-Ab), IgG/IgM S-Ab, and neutralizing antibody (N-Ab) responses of COVID-19-naïve subjects from before their first BNT162b2 vaccination up to 210 days after boosting. Methods: We studied 136 COVID-19-naïve subjects who received three doses of the Pfizer mRNA vaccine (39 males, 97 females, mean age 43.8 ± 13.5 years) from January 2021 to May 2022. Serum was assessed for total S-Ab (Roche), IgG/M (Abbott), and N-Ab (Snibe). Results: Peak antibody levels were measured 20-30 days after each dose, with booster dosing eliciting significantly higher peak antibodies than the second dose: total S-Ab 2219 vs. 19,551 BAU/mL (difference 16,667 BAU/mL, p < 0.0001); IgG 2270 vs. 2932 BAU/mL (difference 660 BAU/mL, p = 0.04); and N-Ab 3.52 vs. 26.4 µg/mL (difference 21.4 µg/mL, p < 0.0001). Only IgM showed a lower peak post-booster antibody titer (COI 2.11 vs. 0.23, difference 1.63, 95% CI 1.05 to 2.38, p < 0.0001). By 180−210 days after the second or third vaccination, total S-Ab/IgG/N-Ab had decreased by 68.7/93.8/73.6% vs. 82.8/86.3/79.5%. The half-lives of IgG and N-Ab antibodies were longer after the third vaccination (IgG: 65 vs. 34 days, N-Ab: 99 vs. 78 days). Conclusion: Total S-Ab/IgG/N-Ab showed a greater increase post-booster, with IgG/N-Ab having a longer half-life.

Keywords: SARS-CoV-2; booster vaccination; kinetics.

Grants and funding

This research received no external funding. We would like to acknowledge Roche Diagnostics, Singapore, Abbott Diagnostics, Singapore, and Snibe Diagnostics, Singapore for providing test kits for this study.