inclusion criteria: 1. volunteers aged 18 and above at the time of screening; 2. volunteers can provide with informed consent and sign informed consent form (icf); 3. have received covid-19 vaccine, and the interval between the last vaccination ≥ 3 months.

inclusion criteria: 1. volunteers aged 18 and above at the time of screening; 2. volunteers can provide with informed consent and sign informed consent form (icf); 3. have received covid-19 vaccine, and the interval between the last vaccination ≥ 3 months.

inclusion criteria: volunteers aged 18 and above at the time of screening; volunteers can provide with informed consent and sign informed consent form (icf); have received covid-19 vaccine, and the interval between the last vaccination ≥ 3 months.

inclusion criteria: volunteers aged 18 and above at the time of screening; volunteers can provide with informed consent and sign informed consent form (icf); have received covid-19 vaccine, and the interval between the last vaccination ≥ 3 months.