The subjects aged 60 years and above with chronic bronchitis and chronic obstructive pulmonary disease were recruited to receive the schedule of two doses inactivated COVID-19 vaccine with the interval of 21 days .~Blood samples will be collected 2 times: before the 1st dose of vaccinatioin and 28 days after the 2nd dose of vaccination.~Any local or systemic adverse events that occurred within 21 days after vaccination will be recorded.
Evaluation of immunogenicity and safety of the subjects aged 60 years and above with chronic bronchitis and chronic obstructive pulmonary disease recruited to receive the schedule of two doses inactivated COVID-19 vaccine with the interval of 21 days .