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 comirnaty (code name: bnt162b2) for 2 doses and who had a minimum of 90 days and a maximum of 240 days after the second dose, 4. subjects with a minimum of 28 days and a maximum of 42 days between 1st and 2nd dose of comirnaty (code name: bnt162b2) vaccines, 5. female subjects of childbearing potential and male subjects of to have child potential who are willing to ensure that they or their partner use effective contraception continuously from 1 month before vaccination to 3 months after booster 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.

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 comirnaty (code name: bnt162b2) for 2 doses and who had a minimum of 90 days and a maximum of 240 days after the second dose, 4. subjects with a minimum of 28 days and a maximum of 42 days between 1st and 2nd dose of comirnaty (code name: bnt162b2) vaccines, 5. female subjects of childbearing potential and male subjects of to have child potential who are willing to ensure that they or their partner use effective contraception continuously from 1 month before vaccination to 3 months after booster 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.

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 comirnaty (code name: bnt162b2) for 2 doses and who had a minimum of 90 days and a maximum of 240 days after the second dose, subjects with a minimum of 28 days and a maximum of 42 days between 1st and 2nd dose of comirnaty (code name: bnt162b2) vaccines, female subjects of childbearing potential and male subjects of to have child potential who are willing to ensure that they or their partner use effective contraception continuously from 1 month before vaccination to 3 months after booster 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.

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 comirnaty (code name: bnt162b2) for 2 doses and who had a minimum of 90 days and a maximum of 240 days after the second dose, subjects with a minimum of 28 days and a maximum of 42 days between 1st and 2nd dose of comirnaty (code name: bnt162b2) vaccines, female subjects of childbearing potential and male subjects of to have child potential who are willing to ensure that they or their partner use effective contraception continuously from 1 month before vaccination to 3 months after booster 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.

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 comirnaty (code name: bnt162b2) for 2 doses and who had a minimum of 180 days and a maximum of 240 days after the second dose, subjects may have a controlled or moderate comorbidity, female subjects who are 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.

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 comirnaty (code name: bnt162b2) for 2 doses and who had a minimum of 180 days and a maximum of 240 days after the second dose, subjects may have a controlled or moderate comorbidity, female subjects who are 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.