inclusion criteria: 1. axillary temperature ≤37.0 ℃. 2. aged 18 years and above, after 3, 4, 5, or 6 months since finished two doses schedule of institute of medical biology chinese academy of medical sciences sars-cov-2 inactivated vaccine. 3. proven legal identity, could come each visit. 4. participants should understand the contents of the informed consent form, the vaccine in this trial, voluntarily sign the informed consent form.

inclusion criteria: 1. axillary temperature ≤37.0 ℃. 2. aged 18 years and above, after 3, 4, 5, or 6 months since finished two doses schedule of institute of medical biology chinese academy of medical sciences sars-cov-2 inactivated vaccine. 3. proven legal identity, could come each visit. 4. participants should understand the contents of the informed consent form, the vaccine in this trial, voluntarily sign the informed consent form.

inclusion criteria: axillary temperature ≤37.0 ℃. aged 18 years and above, after 3, 4, 5, or 6 months since finished two doses schedule of institute of medical biology chinese academy of medical sciences sars-cov-2 inactivated vaccine. proven legal identity, could come each visit. participants should understand the contents of the informed consent form, the vaccine in this trial, voluntarily sign the informed consent form.

inclusion criteria: axillary temperature ≤37.0 ℃. aged 18 years and above, after 3, 4, 5, or 6 months since finished two doses schedule of institute of medical biology chinese academy of medical sciences sars-cov-2 inactivated vaccine. proven legal identity, could come each visit. participants should understand the contents of the informed consent form, the vaccine in this trial, voluntarily sign the informed consent form.