Evaluation of immunogenicity, safety and persistence of the subjects aged 60 years and above with chronic bronchitis and chronic obstructive pulmonary disease received the third dose of inactivated COVID-19 vaccine .

The subjects aged 60 years and above with chronic bronchitis and chronic obstructive pulmonary disease recruited to receive a third dose of inactivated COVID-19 vaccine.

Blood samples will be collected 3 times: before the third dose of vaccinatioin，28 days and 6 months after the third dose of vaccination.

Any local or systemic adverse events that occurred within 21 days after vaccination will be recorded.

Inclusion Criteria:

• Subjects aged 60 and above with full capacity for civil conduct;
• Chronic bronchitis (or chronic obstructive pulmonary disease) diagnosed by a medical institution at level I or above;
• Body temperature < 37.3 ° C confirmed by clinical examination before enrollment ;
• Able and willing to complete the entire study plan during the study follow-up period;
• Have the ability to understand the study procedures, voluntarily sign informed consent, and comply with the requirements of the clinical study protocol;
• Subjects participating in the past clinical trial have completed two doses of COVID-19 vaccine and blood collection before and after immunization;

Exclusion Criteria:

• Subjects were previously confirmed cases of COVID-19 or asymptomatic infected persons;
• Being allergic to any component of vaccines (including excipients) ;
• Injection of non-specific immunoglobulin within 1 month before enrollment;
• Injection of live attenuated vaccines within 1 month and injection of other vaccines within 14 days before enrollment;
• Subjects who have experienced severe allergic reactions to vaccines (e.g. acute anaphylaxis, urticaria, angioneurotic edema, dyspnea, etc.);
• Having uncontrolled epilepsy and other progressive neurological disorders and a history of Guillain-Barre syndrome;
• Having severe liver and kidney diseases, malignant tumors, acute diseases or acute episodes of chronic diseases;
• Have been diagnosed with congenital or acquired immunodeficiency, HIV infection, lymphoma, leukaemia or other autoimmune diseases;
• Have been diagnosed with thrombocytopenia or other clotting disorders that may contraindicate subcutaneous injection;
• During an acute episode of chronic bronchitis/chronic obstructive pulmonary disease;
• Subjects who had vaccine-related adverse reactions after the second dose;
• Having high fever (axillary temperature ≥39.0℃) for three days after the second dose of inoculation, or severe allergic reaction;
• Having any adverse nervous system reaction after the second dose;
• During the acute onset of a chronic disease, or the recovery of acute complications less than two weeks;
• Other reasons for exclusion considered by the investigator.