Neutralizing and Total/IgG Spike Antibody Responses Following Homologous CoronaVac vs. BNT162b2 Vaccination Up to 90 Days Post-Booster

Chin Shern Lau; John Thundyil; May Lin Helen Oh; Soon Kieng Phua; Ya Li Liang; Yanfeng Li; Jianxin Huo; Yuhan Huang; Biyan Zhang; Shengli Xu; Tar Choon Aw

doi:10.3390/antib11040070

Neutralizing and Total/IgG Spike Antibody Responses Following Homologous CoronaVac vs. BNT162b2 Vaccination Up to 90 Days Post-Booster

Antibodies (Basel). 2022 Nov 8;11(4):70. doi: 10.3390/antib11040070.

Authors

Chin Shern Lau¹, John Thundyil², May Lin Helen Oh³, Soon Kieng Phua¹, Ya Li Liang¹, Yanfeng Li⁴, Jianxin Huo⁵, Yuhan Huang⁵, Biyan Zhang⁵, Shengli Xu^{5

6}, Tar Choon Aw^{1

7

8}

Affiliations

¹ Department of Laboratory Medicine, Changi General Hospital, Singapore 529889, Singapore.
² Medical Affairs, Abbott, Singapore 189352, Singapore.
³ Department of Infectious Diseases, Changi General Hospital, Singapore 529889, Singapore.
⁴ GenScript Biotech (Singapore) Pte Ltd., Singapore 349248, Singapore.
⁵ Singapore Immunology Network, Agency for Science, Technology and Research, Singapore 138648, Singapore.
⁶ Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore.
⁷ Department of Medicine, National University of Singapore, Singapore 117599, Singapore.
⁸ Academic Pathology Program, Duke-NUS Medical School, Singapore 169857, Singapore.

Abstract

Introduction: We documented the total spike antibody (S-Ab), IgG S-Ab and neutralizing antibody (N-Ab) responses of BNT162b2/CoronaVac vaccinees up to 90 days post-booster dose.

Methods: We included 32 homologous regimen CoronaVac vaccinees and 136 BNT162b2 mRNA vaccinees. We tested their total S-Ab (Roche), IgG (Abbott) and N-Ab (Snibe) levels at set time points from January 2021 to April 2022. All subjects were deemed to be COVID-19-naïve either via clinical history (CoronaVac vaccinees) or nucleocapsid antibody testing (BNT162b2 vaccinees).

Results: All antibodies peaked 20-30 days post-inoculation. In BNT162b2 vaccinees, all post-booster antibodies were significantly higher than second-dose peaks. In CoronaVac vaccinees, IgG showed no significant differences between peak third-/second-dose titers (difference of 56.0 BAU/mL, 95% CI of -17.1 to 129, p = 0.0894). The post-vaccination titers of all antibodies in BNT162b2 vaccinees were significantly higher than those in CoronaVac vaccinees at all time points. Post-booster, all antibodies declined in 90 days; the final total/IgG/N-Ab titers were 7536 BAU/mL, 1276 BAU/mL and 12.5 μg/mL in BNT162b2 vaccinees and 646 BAU/mL, 62.4 BAU/mL and 0.44 μg/mL in CoronaVac vaccinees.

Conclusion: The mRNA vaccine generated more robust total S-Ab, IgG and N-Ab responses after the second and third vaccinations.

Keywords: BNT162b2; CoronaVac; SARS-CoV-2; antibodies; vaccination.

Grants and funding

This research received no external funding. We would like to thank Abbott Diagnostics, Singapore, for providing assay kits for this study.