Study design
RECRUITMENT
We conducted a multicenter, parallel-group, active-control, non-inferiority clinical trial with pragmatic considerations comparing the safety and efficacy of Fakhravac and BBIBP-Corv2 vaccines. It started with two randomized and double-blind arms. We added two additional non-randomized and open-label arms of Fakhravac and BBIBP-Corv2 because of slow recruitment (Comprehensive cohort study design). Participants who declared unwillingness to randomization were retained in the study, but their vaccine choice was based on their preference [This study was conducted in collaboration with the Iran University of Medical Science (IUMS) clinical trial center as the academic contract research organization (CRO). The National Research Ethics Committee approved the study protocol (IR. NREC.1400.006, 24th August 2021).