Immunogenicity of Mix-and-Match CoronaVac/BNT162b2 Regimen versus Homologous CoronaVac/CoronaVac Vaccination: A Single-Blinded, Randomized, Parallel Group Superiority Trial
Samar Samoud,
Jihene Bettaieb,
Mariem Gdoura,
Ghassen Kharroubi,
Feriel Ben Ghachem,
Imen Zamali,
Ahlem Ben Hmid,
Sadok Salem,
Ahmed Adel Gereisha,
Mongi Dellagi,
Nahed Hogga,
Adel Gharbi,
Amor Baccouche,
Manel Gharbi,
Chadha Khemissi,
Ghada Akili,
Wissem Slama,
Nabila Chaieb,
Yousr Galai,
Hechmi Louzir,
Henda Triki,
Melika Ben Ahmed
Affiliations
Samar Samoud
Department of Clinical Immunology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Jihene Bettaieb
Department of Medical Epidemiology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Mariem Gdoura
Department of Clinical Virology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Ghassen Kharroubi
Department of Medical Epidemiology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Feriel Ben Ghachem
Vaccination Center of Ariana City, Ariana Regional Health Directorate, Ariana 2080, Tunisia
Imen Zamali
Department of Clinical Immunology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Ahlem Ben Hmid
Department of Clinical Immunology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Sadok Salem
Department of Medical Epidemiology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Ahmed Adel Gereisha
Department of Clinical Immunology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Mongi Dellagi
Department of Medical Epidemiology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Nahed Hogga
Department of Clinical Virology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Adel Gharbi
Department of Medical Epidemiology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Amor Baccouche
Department of Medical Epidemiology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Manel Gharbi
Department of Clinical Virology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Chadha Khemissi
Department of Clinical Virology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Ghada Akili
Vaccination Center of Ariana City, Ariana Regional Health Directorate, Ariana 2080, Tunisia
Wissem Slama
Vaccination Center of Ariana City, Ariana Regional Health Directorate, Ariana 2080, Tunisia
Nabila Chaieb
Vaccination Center of Ariana City, Ariana Regional Health Directorate, Ariana 2080, Tunisia
Yousr Galai
Department of Clinical Immunology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Hechmi Louzir
Department of Clinical Immunology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
Henda Triki
Laboratory of Transmission, Control and Immunobiology of Infections (LR11IPT02), Institut Pasteur de Tunis, University of Tunis El Manar, Tunis 1068, Tunisia
Melika Ben Ahmed
Department of Clinical Immunology, Pasteur Institute of Tunis, Tunis 1002, Tunisia
(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.
