This is a Phase 2, randomised, and double-blinded study. The participants will be randomised to receive either the investigational product or the placebo at a ratio of 2:1. 0.5 mL of the assigned vaccine will be administered as an IM injection. Each participant will be followed up for 6 months after vaccination.~The primary objective aims to assess the safety, tolerability, and reactogenicity of Baiya SARS-CoV-2 Vax 2 vaccine in adults (18-64 years old) as a booster vaccination following vaccination with the alternate and widely used COVID-19 vaccines, which are AstraZeneca vaccine or mRNA vaccine.~The secondary objective aims to evaluate safety, tolerability, reactogenicity, and immunogenicity up to 28 days after the booster vaccination.~An interim analysis of all safety and available immunogenicity data up to Visit 6 (Day 29 ±3) will be conducted for the DSMB review.
The investigational product Baiya SARS-CoV-2 Vax 2 vaccine is a second-generation of protein subunit vaccine from plant to prevent COVID-19 disease.~This is a Phase 2, randomised, and double-blinded study to assess the safety, tolerability, reactogenicity and immunogenicity of Baiya SARS-CoV-2 Vax 2 vaccine, when used as a booster vaccination following vaccination with the alternate and widely used COVID-19 vaccines, which are AstraZeneca vaccine or mRNA vaccine.