A Longitudinal Study of Humoral Immune Responses Induced by a 3-Dose Inactivated COVID-19 Vaccine in an Observational, Prospective Cohort
16 Pages Posted: 1 Mar 2022
Abstract
Objective: To quantify the dynamic SARS-CoV-2 specific antibody levels induced by an inactivated COVID-19 vaccine, CoronaVac.
Methods: An observational, prospective cohort study was performed with 93 healthy healthcare workers from a tertiary hospital in Nanjing, China. Serum SARS-CoV-2 specific IgM, IgG, and ACE2-blocking antibodies were measured at seven time points among participants who received 3 doses of inactivated COVID-19 vaccine.
Results: SARS-CoV-2 specific IgG and ACE2-blocking antibody seroconversion rate is high after receiving primary and booster immunization. Besides, vaccine immune responses were negatively correlated with age. Additionally, SARS-CoV-2 specific IgG and ACE-2-blocking antibody titers were highly correlated with neutralization titers of D614G, Omicron, and Delta strain.
Conclusions: CoronaVac elicited robust SARS-CoV-2 specific IgM, IgG and ACE2-blocking antibody responses. Monitoring SARS-CoV-2 antibody responses induced by vaccination would provide important guidance for the immunogenicity evaluation of COVID-19 vaccines.
Note:
Funding Information: This study was supported by Clinical Trials from the Affiliated Drum Tower Hospital, Medical School of Nanjing University (2021-LCYJ-PY-09), Nanjing Important Science & Technology Specific Projects (2021-11005), Nanjing Medical Science and Technique Development Foundation (QRX17141 and YKK19056), Social Development Foundation of Jiangsu Province BE2021739).
Conflict of Interests: The authors have declared that no conflict of interest exists.
Ethical Approval: The study design has been approved by the Ethics Committee of Nanjing Drum Tower Hospital (2021-034-01).
Trial Registration: This study has been registered with ClinicalTrials.gov (NCT04729374).
Keywords: COVID-19, SARS-CoV-2, humoral immune responses, vaccine, booster
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