Journal Article

Immunogenicity of Mix-and-Match CoronaVac/BNT162b2 Regimen versus Homologous CoronaVac/CoronaVac Vaccination: A Single-Blinded, Randomized, Parallel Group Superiority Trial

Ben Hmid, Ahlem, Bettaieb, Jihene, Gharbi, Adel, Chaieb, Nabila, Gereisha, Ahmed Adel, Dellagi, Mongi, Louzir, Hechmi, Galai, Yousr, Hogga, Nahed, Zamali, Imen, Baccouche, Amor, Ben Ghachem, Feriel, Salem, Sadok, Gharbi, Manel, Ben Ahmed, Melika, Khemissi, Chadha, Gdoura, Mariem, Kharroubi, Ghassen, Samoud, Samar, Triki, Henda, Akili, Ghada, Slama, Wissem

2023

Overview

(1) Background: This study aimed to compare the immunogenicity of the mix-and-match CoronaVac/BNT162b2 vaccination to the homologous CoronaVac/CoronaVac regimen. (2) Methods: We conducted a simple-blinded randomized superiority trial to measure SARS-CoV-2 neutralization antibodies and anti-spike receptor binding domain (RBD) IgG concentrations in blood samples of participants who had received the first dose of CoronaVac vaccine followed by a dose of BNT162b2 or CoronaVac vaccine. The primary endpoint for immunogenicity was the serum-neutralizing antibody level with a percentage of inhibition at 90% at 21–35 days after the boost. A difference of 25% between groups was considered clinically relevant. (3) Results: Among the 240 eligible participants, the primary endpoint data were available for 100 participants randomly allocated to the mix-and-match group versus 99 participants randomly allocated to the homologous dose group. The mix-and-match regimen elicited significantly higher levels of neutralizing antibodies (median level of 96%, interquartile range (IQR) (95–97) versus median level of 94%, IQR (81–96) and anti-spike IgG antibodies (median level of 13,460, IQR (2557–29,930) versus median level of 1190, IQR (347–4964) compared to the homologous group. Accordingly, the percentage of subjects with a percentage of neutralizing antibodies > 90% was significantly higher in the mix-and-match group (90.0%) versus the homologous (60.6%). Interestingly, no severe events were reported within 30 days after the second dose of vaccination in both groups. (4) Conclusions: Our data showed the superiority of the mix-and-match CoronaVac/BNT162b2 vaccination compared to the CoronaVac/CoronaVac regimen in terms of immunogenicity, thus constituting a proof-of-concept study supporting the use of inactivated vaccines in a mix-and-match strategy while ensuring good immunogenicity and safety.

• Publisher: MDPI AG,MDPI
• Subject: Antibodies / BNT162b2 / Clinical trials / Comparative analysis / CoronaVac / COVID-19 / COVID-19 vaccines / Homology / Immunogenetics / Immunogenicity / Immunoglobulin G / Infections / International organizations / Life Sciences / Neutralization / Neutralizing / R&D / Research & development / Severe acute respiratory syndrome coronavirus 2 / tolerance / Vaccines