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The Immunogenicity and Safety of Different COVID-19 Booster Vaccination Following CoronaVac or ChAdOx1 nCoV-19 Primary Series
37 Pages Posted: 7 Dec 2021
More...Abstract
Background: The appropriate COVID-19 booster vaccine following inactivated or adenoviral vector COVID-19 vaccination is unclear.
Methods: We prospectively enrolled healthy adults who completed a 2-dose homologous primary series of either inactivated vaccine (CoronaVac) or chimpanzee adenoviral-vector vaccine (ChAdOx1) 8-12 weeks earlier, and allocated them to receive one of the following booster vaccine: inactivated (BBIBP-CorV), ChAdOx1, or mRNA (BNT162b2 at full [30µg] and half [15µg] dose) vaccines. We determined the reactogenicity and the immune responses post-booster. Anti-receptor binding domain IgG (anti-RBD-IgG) geometric mean concentration (GMCs), neutralising antibodies titres (GMT) against Delta and Beta variants, and interferon gamma (IFN-ϒ) responses were determined.
Findings: Of the 352 participants, 285 (81%) were female, and the median age (IQR) was 39 (31-47) years. Overall, the adverse events for all booster vaccines were mild to moderate. Two weeks post-booster dose, 30µg-BNT162b2 induced the highest anti-RBD IgG GMCs in the CoronaVac-prime and ChAdOx1-prime groups (5152 and 2364 BAU/mL), followed by 15µg-BNT162b2 (3981 and 1962 BAU/mL), ChAdOx1 (1358 and 246 BAU/mL), and BBIBP-CorV (154 and 128 BAU/mL), respectively. The GMT against the Delta variant were also highest with 30µg-BNT162b2 (411 and 470) and 15µg-BNT162b2 (499 and 358); followed by ChAdOx1 (271 and 69), and BBIBP-CorV (61·3 and 49). The GMTs against Beta variant were lower but in the same trend. Overall BNT162b2 also induced higher IFN-ϒ response.
Interpretation: Heterologous boosting vaccination with BNT162b2 is the most immunogenic following CoronaVac or ChAdOx1 primary series. A lower dose BNT162b2 may be used as booster in settings with limited vaccine supply.
Clinical Trial Registration Details: The study was registered in thaichinicaltrials.org (TCTR20210719006).
Funding Information: The National Research Council of Thailand.
Declaration of Interests: All authors declare no personal or professional conflicts of interest, and no financial support from the companies that produce and/or distribute the drugs, devices, or materials described in this report.
Ethics Approval Statement: The study procedures, risks, and benefits were explained to all participants before obtaining written informed consent. The procedures in this study adhere to the tenets of the Declaration of Helsinki. The study protocol was approved by the Siriraj Institutional Review Board (COA no. Si 537/2021).
Keywords: Booster, COVID-19, CoronaVac, ChAdOx1, vaccine
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