inclusion criteria: 1. ability to provide written informed consent. 2. participants of either gender of age ≥18 years. 3. received and completed covid-19 vaccine under emergency use authorization (eua) dosing guidelines at least 6 ± 1 month (after receipt of second dose of eua vaccine) prior to enrollment, confirmed by the electronic covid-19 certificate (cowin). 4. expressed interest and availability to fulfill the study requirements. 5. for a female participant of child-bearing potential, planning to avoid becoming pregnant (use of an effective method of contraception or abstinence) from the time of study enrolment until at least four weeks after the vaccination. 6. agrees not to participate in another clinical trial at any time during the study period. 7. agrees to remain in the study area for the entire duration of the study. 8. willing to allow storage and future use of biological samples for future research

inclusion criteria: 1. ability to provide written informed consent. 2. participants of either gender of age ≥18 years. 3. received and completed covid-19 vaccine under emergency use authorization (eua) dosing guidelines at least 6 ± 1 month (after receipt of second dose of eua vaccine) prior to enrollment, confirmed by the electronic covid-19 certificate (cowin). 4. expressed interest and availability to fulfill the study requirements. 5. for a female participant of child-bearing potential, planning to avoid becoming pregnant (use of an effective method of contraception or abstinence) from the time of study enrolment until at least four weeks after the vaccination. 6. agrees not to participate in another clinical trial at any time during the study period. 7. agrees to remain in the study area for the entire duration of the study. 8. willing to allow storage and future use of biological samples for future research

inclusion criteria: ability to provide written informed consent. participants of either gender of age ≥18 years. received and completed covid-19 vaccine under emergency use authorization (eua) dosing guidelines at least 6 ± 1 month (after receipt of second dose of eua vaccine) prior to enrollment, confirmed by the electronic covid-19 certificate (cowin). expressed interest and availability to fulfill the study requirements. for a female participant of child-bearing potential, planning to avoid becoming pregnant (use of an effective method of contraception or abstinence) from the time of study enrolment until at least four weeks after the vaccination. agrees not to participate in another clinical trial at any time during the study period. agrees to remain in the study area for the entire duration of the study. willing to allow storage and future use of biological samples for future research

inclusion criteria: ability to provide written informed consent. participants of either gender of age ≥18 years. received and completed covid-19 vaccine under emergency use authorization (eua) dosing guidelines at least 6 ± 1 month (after receipt of second dose of eua vaccine) prior to enrollment, confirmed by the electronic covid-19 certificate (cowin). expressed interest and availability to fulfill the study requirements. for a female participant of child-bearing potential, planning to avoid becoming pregnant (use of an effective method of contraception or abstinence) from the time of study enrolment until at least four weeks after the vaccination. agrees not to participate in another clinical trial at any time during the study period. agrees to remain in the study area for the entire duration of the study. willing to allow storage and future use of biological samples for future research