Immunogenicity of Heterologous Versus Homologous Prime Boost Schedule With mRNA and Inactivated COVID-19 Vaccines

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.

Inclusion Criteria:Acceptance to participate in the study.Age: 18-60 years old.Non-inclusion criteria:Presence of disability (mainly mental disability).Pregnancy.Patients under immunosuppressive treatment or immunocompromised individuals.Prior Covid-19 infection.Exclusion Criteria:Occurrence of a serious adverse event (death, anaphylactic shock, ...).Subjects wishing to withdraw from the study.Occurrence of a SARS-CoV-2 symptomatic infection during the follow-up period.