subjects must meet all of the following inclusion criteria to be eligible for inclusion in the study: inclusion criteria: 1. subjects willing and able to give signed informed consent to participate in study, 2. healthy male or female aged 18 - 59 years (including both groups), 3. subjects who were vaccinated with coronavac for 2 doses and who had a minimum of 90 days and a maximum of 270 days after the second dose, 4. subjects with minimum 28 days and maximum 42 days between coronavac 1st and 2nd dose vaccines, 5. female subjects of childbearing potential should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, male subjects of potential to have children should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, 6. in the opinion of the investigator, subjects capable and willing to comply with all study requirements, 7. subjects are willing to agree to abstain from donating blood during the study. subjects meeting any of the following criteria will not be included in the study:

subjects must meet all of the following inclusion criteria to be eligible for inclusion in the study: inclusion criteria: 1. subjects willing and able to give signed informed consent to participate in study, 2. healthy male or female aged 18 - 59 years (including both groups), 3. subjects who were vaccinated with coronavac for 2 doses and who had a minimum of 90 days and a maximum of 270 days after the second dose, 4. subjects with minimum 28 days and maximum 42 days between coronavac 1st and 2nd dose vaccines, 5. female subjects of childbearing potential should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, male subjects of potential to have children should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, 6. in the opinion of the investigator, subjects capable and willing to comply with all study requirements, 7. subjects are willing to agree to abstain from donating blood during the study. subjects meeting any of the following criteria will not be included in the study:

subjects must meet all of the following inclusion criteria to be eligible for inclusion in the study: inclusion criteria: subjects willing and able to give signed informed consent to participate in study, healthy male or female aged 18 - 59 years (including both groups), subjects who were vaccinated with coronavac for 2 doses and who had a minimum of 90 days and a maximum of 270 days after the second dose, subjects with minimum 28 days and maximum 42 days between coronavac 1st and 2nd dose vaccines, female subjects of childbearing potential should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, male subjects of potential to have children should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, in the opinion of the investigator, subjects capable and willing to comply with all study requirements, subjects are willing to agree to abstain from donating blood during the study. subjects meeting any of the following criteria will not be included in the study:

subjects must meet all of the following inclusion criteria to be eligible for inclusion in the study: inclusion criteria: subjects willing and able to give signed informed consent to participate in study, healthy male or female aged 18 - 59 years (including both groups), subjects who were vaccinated with coronavac for 2 doses and who had a minimum of 90 days and a maximum of 270 days after the second dose, subjects with minimum 28 days and maximum 42 days between coronavac 1st and 2nd dose vaccines, female subjects of childbearing potential should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, male subjects of potential to have children should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, in the opinion of the investigator, subjects capable and willing to comply with all study requirements, subjects are willing to agree to abstain from donating blood during the study. subjects meeting any of the following criteria will not be included in the study:

subjects must meet all of the following inclusion criteria to be eligible for inclusion in the study: inclusion criteria: subjects willing and able to give signed informed consent to participate in study, healthy male or female aged 18 - 60 years (including both groups), subjects who were vaccinated with coronavac for 2 doses and who had a minimum of 90 days and a maximum of 270 days after the second dose, subjects with 4-6 weeks between coronavac 1st and 2nd dose vaccines, female subjects of childbearing potential should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, in the opinion of the investigator, subjects capable and willing to comply with all study requirements, subjects are willing to agree to abstain from donating blood during the study. subjects meeting any of the following criteria will not be included in the study:

subjects must meet all of the following inclusion criteria to be eligible for inclusion in the study: inclusion criteria: subjects willing and able to give signed informed consent to participate in study, healthy male or female aged 18 - 60 years (including both groups), subjects who were vaccinated with coronavac for 2 doses and who had a minimum of 90 days and a maximum of 270 days after the second dose, subjects with 4-6 weeks between coronavac 1st and 2nd dose vaccines, female subjects of childbearing potential should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, in the opinion of the investigator, subjects capable and willing to comply with all study requirements, subjects are willing to agree to abstain from donating blood during the study. subjects meeting any of the following criteria will not be included in the study:

subjects must meet all of the following inclusion criteria to be eligible for inclusion in the study: inclusion criteria: 1. subjects willing and able to give signed informed consent to participate in study, 2. healthy male or female aged 18 - 60 years (including both groups), 3. subjects who were vaccinated with coronavac for 2 doses and who had a minimum of 90 days and a maximum of 270 days after the second dose, 4. subjects with 4-6 weeks between coronavac 1st and 2nd dose vaccines, 5. female subjects of childbearing potential should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, 6. in the opinion of the investigator, subjects capable and willing to comply with all study requirements, 7. subjects are willing to agree to abstain from donating blood during the study. subjects meeting any of the following criteria will not be included in the study:

subjects must meet all of the following inclusion criteria to be eligible for inclusion in the study: inclusion criteria: 1. subjects willing and able to give signed informed consent to participate in study, 2. healthy male or female aged 18 - 60 years (including both groups), 3. subjects who were vaccinated with coronavac for 2 doses and who had a minimum of 90 days and a maximum of 270 days after the second dose, 4. subjects with 4-6 weeks between coronavac 1st and 2nd dose vaccines, 5. female subjects of childbearing potential should be willing to ensure that they or their partner use effective birth control methods continuously from 1 month before and up to 3 months after vaccination, 6. in the opinion of the investigator, subjects capable and willing to comply with all study requirements, 7. subjects are willing to agree to abstain from donating blood during the study. subjects meeting any of the following criteria will not be included in the study: