inclusion criteria: phase i: participants are eligible to be included in the study only if the following conditions are met: male or female aged ≥18 years old when signing icf; participants that were fully vaccinated with mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; ability to read, understand, and fill in record cards; those who are clinically judged to be healthy, the results of physical examination, vital signs and laboratory tests during the screening period are normal, or although beyond the normal reference range, they are judged by investigators to be of no clinical significance; fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening. phase ii: participants are eligible to be included in the study only if the following conditions are met: male or female aged ≥18 years old when signing icf; participants that were fully vaccinated with mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; ability to read, understand, and fill in record cards; healthy participants or participants with pre-existing medical conditions who are in stable condition. the "pre-existing medical conditions" include but not limited to hypertension, diabetes, chronic cholecystitis and cholelithiasis, chronic gastritis that meet the described criteria. a stable medical condition is defined as disease not requiring significant change in therapy or no need for hospitalization as a consequence of worsening disease state for at least 3 months prior to enrollment; fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening.

inclusion criteria: phase i: participants are eligible to be included in the study only if the following conditions are met: male or female aged ≥18 years old when signing icf; participants that were fully vaccinated with mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; ability to read, understand, and fill in record cards; those who are clinically judged to be healthy, the results of physical examination, vital signs and laboratory tests during the screening period are normal, or although beyond the normal reference range, they are judged by investigators to be of no clinical significance; fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening. phase ii: participants are eligible to be included in the study only if the following conditions are met: male or female aged ≥18 years old when signing icf; participants that were fully vaccinated with mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; ability to read, understand, and fill in record cards; healthy participants or participants with pre-existing medical conditions who are in stable condition. the "pre-existing medical conditions" include but not limited to hypertension, diabetes, chronic cholecystitis and cholelithiasis, chronic gastritis that meet the described criteria. a stable medical condition is defined as disease not requiring significant change in therapy or no need for hospitalization as a consequence of worsening disease state for at least 3 months prior to enrollment; fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening.

inclusion criteria: participants are eligible to be included in the study only if the following conditions are met: male or female aged ≥18 years old when signing icf; participants that were fully vaccinated with adenovirus vectored or mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; ability to read, understand, and fill in record cards; phase i participants only: those who are clinically judged to be healthy, the results of physical examination, vital signs and laboratory tests during the screening period are normal, or although beyond the normal reference range, they are judged by investigators to be of no clinical significance; phase ii participants only: healthy participants or participants with pre-existing medical conditions who are in stable condition. a stable medical condition is defined as disease not requiring significant change in therapy or no need for hospitalization as a consequence of worsening disease state for at least 3 months prior to enrollment; fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening.

inclusion criteria: participants are eligible to be included in the study only if the following conditions are met: male or female aged ≥18 years old when signing icf; participants that were fully vaccinated with adenovirus vectored or mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; ability to read, understand, and fill in record cards; phase i participants only: those who are clinically judged to be healthy, the results of physical examination, vital signs and laboratory tests during the screening period are normal, or although beyond the normal reference range, they are judged by investigators to be of no clinical significance; phase ii participants only: healthy participants or participants with pre-existing medical conditions who are in stable condition. a stable medical condition is defined as disease not requiring significant change in therapy or no need for hospitalization as a consequence of worsening disease state for at least 3 months prior to enrollment; fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening.

inclusion criteria: participants are eligible to be included in the study only if the following conditions are met: male or female aged ≥18 years old when signing icf; participants that were fully vaccinated with adenovirus vectored or mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; ability to read, understand, and fill in record cards; phase i participants only: those who are clinically judged to be healthy, the results of physical examination, vital signs and laboratory tests during the screening period are normal, or although beyond the normal reference range, they are judged by investigators to be of no clinical significance; phase ii/iii participants only: healthy participants or participants with pre-existing medical conditions who are in stable condition. a stable medical condition is defined as disease not requiring significant change in therapy or no need for hospitalization as a consequence of worsening disease state for at least 3 months prior to enrollment; fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening.

inclusion criteria: participants are eligible to be included in the study only if the following conditions are met: male or female aged ≥18 years old when signing icf; participants that were fully vaccinated with adenovirus vectored or mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; ability to read, understand, and fill in record cards; phase i participants only: those who are clinically judged to be healthy, the results of physical examination, vital signs and laboratory tests during the screening period are normal, or although beyond the normal reference range, they are judged by investigators to be of no clinical significance; phase ii/iii participants only: healthy participants or participants with pre-existing medical conditions who are in stable condition. a stable medical condition is defined as disease not requiring significant change in therapy or no need for hospitalization as a consequence of worsening disease state for at least 3 months prior to enrollment; fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening.

inclusion criteria: participants are eligible to be included in the study only if the following conditions are met: 1. male or female aged ≥18 years old when signing icf; 2. participants that were fully vaccinated with adenovirus vectored or mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. 3. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; 4. ability to read, understand, and fill in record cards; 5. phase i participants only: those who are clinically judged to be healthy, the results of physical examination, vital signs and laboratory tests during the screening period are normal, or although beyond the normal reference range, they are judged by investigators to be of no clinical significance; 6. phase ii/iii participants only: healthy participants or participants with pre-existing medical conditions who are in stable condition. a stable medical condition is defined as disease not requiring significant change in therapy or no need for hospitalization as a consequence of worsening disease state for at least 3 months prior to enrollment; 7. fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening.

inclusion criteria: participants are eligible to be included in the study only if the following conditions are met: 1. male or female aged ≥18 years old when signing icf; 2. participants that were fully vaccinated with adenovirus vectored or mrna anti-sars-cov-2 vaccine, and the last dose is ≥6 months away from the vaccination of this study. 3. participants that can sign written icf and voluntarily participate in the trial, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial; 4. ability to read, understand, and fill in record cards; 5. phase i participants only: those who are clinically judged to be healthy, the results of physical examination, vital signs and laboratory tests during the screening period are normal, or although beyond the normal reference range, they are judged by investigators to be of no clinical significance; 6. phase ii/iii participants only: healthy participants or participants with pre-existing medical conditions who are in stable condition. a stable medical condition is defined as disease not requiring significant change in therapy or no need for hospitalization as a consequence of worsening disease state for at least 3 months prior to enrollment; 7. fertile men and women of childbearing age voluntarily agree to take effective contraceptive measures from signing icf to 6 months after the study vaccination; the pregnancy test results of women of childbearing age are negative on screening.