Immunogenicity of Heterologous Versus Homologous Prime Boost Schedule With mRNA and Inactivated COVID-19 Vaccines
Condition: COVID-19
MeSH terms: COVID-19
Study type: Interventional
Phase: Phase 3

Summary: 
      This study is a randomized, simple-blinded comparative phase III clinical trial comparing the
      immunogenicity of two doses Coronovac to that of a first dose of Coronovac (Sinovac, Beijing,
      China) followed by a booster shot with the mRNA-based BNT162b2 SARS-CoV-2 vaccine (Comirnaty,
      Pfizer-BioNTech).

      The purpose of this study is to evaluate the superiority, safety and immunogenicity of the
      heterologous prime-boost CoronaVac/BNT162b2 vaccination to the homologous CoronaVac/CoronaVac
      regimen.
    

Detailed description: 
      This study is a randomized simple-blinded comparative phase III clinical trial in COVID-19
      vaccine naïve volunteers adults aged between 18 and 60 years. The purpose of this study is to
      evaluate the superiority, safety and immunogenicity of the heterologous prime-boost
      CoronaVac/BNT162b2 vaccination to the homologous CoronaVac/CoronaVac regimen. The study is
      conducted in four different sites located in the North of Tunisia.

      A total of 240 eligible participants were included. Among them, the primary end point data
      were available for 100 participants randomly allocated to heterologous boost group versus 99
      participants randomly allocated to homologous boost dose group.

      Participants are assigned to receive either two injections of the CoronaVac vaccine (1st and
      2nd vaccine), or CoronaVac as 1st dose and Pfizer as 2nd dose in 3 to 4 weeks interval.

      A blood sample (5ml of the whole blood) is collected for each participant at the vaccination
      center before the first dose injection. After verifying the absence of a SARS-CoV-2 infection
      during the interrogation (a follow-up survey), a 2nd blood sample (5ml of whole blood) is
      taken for each participant at the vaccination center before the second dose injection. After
      the two injections, a 3rd blood sample (5ml of whole blood) will be taken for each
      participant between day 21 and day 35 after the second dose. Data collection and all samples
      are treated at Institute Pasteur of Tunis.
    

Intervention name(s): CoronaVac/CoronaVac; CoronaVac/BNT162b2
Intervention type(s): Biological; Biological
Intervention description(s): Two doses at 21-day +/- 3 days. Each innoculation dose is 0.5 ml containing 600 SU in-house unit (equals to 3μg) of SARS-CoV-2 antigen.; First dose of Coronavac. Each innoculation dose is 0.5 ml containing 600 SU in-house unit (equals to 3μg) of SARS-CoV-2 antigen.
Second dose of BNT162b2 at 21-day +/- 3 days. Each dose of the Pfizer-BioNTech COVID-19 Vaccine is 0.3 ml. Each prefilled syringe contains 30 mcg of a nucleoside-modified messenger RNA (modRNA) encoding the viral spike (S) glycoprotein of SARS-CoV-2
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Randomized simple-blinded comparative phase III clinical trial
Masking: Single (Participant)
Primary purpose: Prevention
Keywords: Vaccine; Immunogenicity; Heterologous prime-boost; Coronavac; Pfizer-BioNtech