inclusion criteria: * 6-59 years of age at the time of enrollment; * able to provide consent or obtain consent from guardian to participate in the trial and sign an informed consent form (icf); * able and willing to complete all the scheduled study procedures during the whole study follow-up period; * axillary temperature ≤37.0℃; * igg ang igm negative for covid-19; * have not received any type of covid-19 vaccines; * no contact history of covid-19; no travel history to medium and high risk regions and abroad in the past 21 days; * participants who are clinically determined to be healthy after checking medical history and physical examination are eligible to receive the product.

inclusion criteria: * 6-59 years of age at the time of enrollment; * able to provide consent or obtain consent from guardian to participate in the trial and sign an informed consent form (icf); * able and willing to complete all the scheduled study procedures during the whole study follow-up period; * axillary temperature ≤37.0℃; * igg ang igm negative for covid-19; * have not received any type of covid-19 vaccines; * no contact history of covid-19; no travel history to medium and high risk regions and abroad in the past 21 days; * participants who are clinically determined to be healthy after checking medical history and physical examination are eligible to receive the product.

inclusion criteria: - 6-59 years of age at the time of enrollment; - able to provide consent or obtain consent from guardian to participate in the trial and sign an informed consent form (icf); - able and willing to complete all the scheduled study procedures during the whole study follow-up period; - axillary temperature ≤37.0℃; - igg ang igm negative for covid-19; - have not received any type of covid-19 vaccines; - no contact history of covid-19; no travel history to medium and high risk regions and abroad in the past 21 days; - participants who are clinically determined to be healthy after checking medical history and physical examination are eligible to receive the product.

inclusion criteria: - 6-59 years of age at the time of enrollment; - able to provide consent or obtain consent from guardian to participate in the trial and sign an informed consent form (icf); - able and willing to complete all the scheduled study procedures during the whole study follow-up period; - axillary temperature ≤37.0℃; - igg ang igm negative for covid-19; - have not received any type of covid-19 vaccines; - no contact history of covid-19; no travel history to medium and high risk regions and abroad in the past 21 days; - participants who are clinically determined to be healthy after checking medical history and physical examination are eligible to receive the product.