The subjects aged 60 years and above with chronic bronchitis and chronic obstructive pulmonary disease were recruited to receive three doses of inactivated COVID-19 vaccine on day 0, day 21 and day 111, respectively.~Blood samples were collected before the first dose, 28 days after the second dose, before the third dose, 28 days after the third dose and 6 months after the third dose, respectively.~Any local or systemic adverse events that occurred within 21/28 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 three doses of inactivated COVID-19 vaccine on day 0, day 21 and day 111, respectively .