IN-006

Primary objectives: 1) To evaluate the safety and reactogenicity of a single dose of IN006 in healthy subjects aged 60 years and above; 2) To evaluate the humoral immune response 28 days after the first vaccination of IN006 in healthy subjects aged 60 years and above. Secondary objectives: To evaluate the persistence of humoral immunity in healthy subjects aged 60 years and above after the first vaccination of IN006.