inclusion criteria: participants are eligible to be included in the study only if all of the following criteria apply: type of participant * participants who have willingness and ability to comply with study requirements/procedures (if applicable, with assistance by legally authorised representative) based on the assessment of the investigator. * participants who have not yet received 3 doses of covid-19 vaccine (2 as primary series and a booster dose). persons who have received no prior vaccination are eligible to enroll at day 0 to start a primary series. persons who have received a single dose of covid-19 vaccine at least 8 week prior (note that this includes persons who have received a single dose of johnson \& johnson vaccine) are eligible to enroll at day 70 to complete their primary series and receive a booster dose 3 months thereafter. persons who have received a primary series of covid-19 vaccine at least 3 months prior are eligible to enroll at day 170 to receive a booster. * informed consent * capable of giving signed informed consent, as described in appendix a, which includes compliance with the requirements and restrictions listed in the informed consent form (icf) and in this protocol. * note: a separate informed consent will be used for optional sample collection. * provision of signed and dated written icf prior to any mandatory study specific procedures, sampling, and analyses. * age * participant must be ≥ 18years of age at the time of signing the informed consent and residing in the catchment area of select hospitals in botswana.

inclusion criteria: participants are eligible to be included in the study only if all of the following criteria apply: type of participant * participants who have willingness and ability to comply with study requirements/procedures (if applicable, with assistance by legally authorised representative) based on the assessment of the investigator. * participants who have not yet received 3 doses of covid-19 vaccine (2 as primary series and a booster dose). persons who have received no prior vaccination are eligible to enroll at day 0 to start a primary series. persons who have received a single dose of covid-19 vaccine at least 8 week prior (note that this includes persons who have received a single dose of johnson \& johnson vaccine) are eligible to enroll at day 70 to complete their primary series and receive a booster dose 3 months thereafter. persons who have received a primary series of covid-19 vaccine at least 3 months prior are eligible to enroll at day 170 to receive a booster. * informed consent * capable of giving signed informed consent, as described in appendix a, which includes compliance with the requirements and restrictions listed in the informed consent form (icf) and in this protocol. * note: a separate informed consent will be used for optional sample collection. * provision of signed and dated written icf prior to any mandatory study specific procedures, sampling, and analyses. * age * participant must be ≥ 18years of age at the time of signing the informed consent and residing in the catchment area of select hospitals in botswana.

inclusion criteria: participants are eligible to be included in the study only if all of the following criteria apply: type of participant participants who have willingness and ability to comply with study requirements/procedures (if applicable, with assistance by legally authorised representative) based on the assessment of the investigator. participants who have not yet received 3 doses of covid-19 vaccine (2 as primary series and a booster dose). persons who have received no prior vaccination are eligible to enroll at day 0 to start a primary series. persons who have received a single dose of covid-19 vaccine at least 8 week prior (note that this includes persons who have received a single dose of johnson & johnson vaccine) are eligible to enroll at day 70 to complete their primary series and receive a booster dose 3 months thereafter. persons who have received a primary series of covid-19 vaccine at least 3 months prior are eligible to enroll at day 170 to receive a booster. informed consent capable of giving signed informed consent, as described in appendix a, which includes compliance with the requirements and restrictions listed in the informed consent form (icf) and in this protocol. note: a separate informed consent will be used for optional sample collection. provision of signed and dated written icf prior to any mandatory study specific procedures, sampling, and analyses. age participant must be ≥ 18years of age at the time of signing the informed consent and residing in the catchment area of select hospitals in botswana.

inclusion criteria: participants are eligible to be included in the study only if all of the following criteria apply: type of participant participants who have willingness and ability to comply with study requirements/procedures (if applicable, with assistance by legally authorised representative) based on the assessment of the investigator. participants who have not yet received 3 doses of covid-19 vaccine (2 as primary series and a booster dose). persons who have received no prior vaccination are eligible to enroll at day 0 to start a primary series. persons who have received a single dose of covid-19 vaccine at least 8 week prior (note that this includes persons who have received a single dose of johnson & johnson vaccine) are eligible to enroll at day 70 to complete their primary series and receive a booster dose 3 months thereafter. persons who have received a primary series of covid-19 vaccine at least 3 months prior are eligible to enroll at day 170 to receive a booster. informed consent capable of giving signed informed consent, as described in appendix a, which includes compliance with the requirements and restrictions listed in the informed consent form (icf) and in this protocol. note: a separate informed consent will be used for optional sample collection. provision of signed and dated written icf prior to any mandatory study specific procedures, sampling, and analyses. age participant must be ≥ 18years of age at the time of signing the informed consent and residing in the catchment area of select hospitals in botswana.