This is a global phase III clinical trial to evaluate efficacy,safety, immuogenicity of Ad5-nCoV manufactured by Cansino and Beijing Institute of Biotechnology in health adults aged 18 years old and above.

The study will be double-blind, placebo-controlled trial with participants randomly allocated 1:1 to placebo and experimental vaccine cohorts.

The immunization schedule is one doses intramuscular injections (deltoid).