Inclusion criteria  Age 18 and older Health care worker in the private or public service The President and Deputy President of South Africa* (The President and Deputy President of South Africa have been included in the protocol to address the issue of vaccine hesitancy. ) Willingness and ability to comply vaccination plan and other study procedures. Capable of giving electronic or personal signed informed consent as described in Appendix 5, which includes compliance with the requirements in this protocol.  Inclusion criteria for the sub-cohort  Age 18 and older Health care worker in the private or public service Willingness and ability to comply with all scheduled visits, vaccination plan, laboratory tests, and other study procedures, with follow-up at an ENSEMBLE site. Capable of giving electronic or personal signed informed consent as described in Appendix 5, which includes compliance with the requirements in this protocol.  Exclusion criteria  Any significant acute or chronic medical condition, situation or circumstance that in the opinion of the PI/designee makes the participant unsuitable for participation in the study, or jeopardises the safety or rights of the participant Participant reports being pregnant at time of enrolment, planning conception within 3 months. Participants who report breastfeeding at the time of enrolment will be excluded. Current participation in any other research studies that would interfere with the objectives of this study. The determination of whether participation in another study would be exclusionary for a given participant will be made by the PI/designee. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine. Participants who have experienced major venous and arterial thrombosis occurring with thrombocytopenia following vaccination with any COVID-19 vaccine should not enrol in Sisonke. Participants with a history of heparin-induced thrombocytopenia.  Note:  • Vaccination within 14-90 days with other COVID19 or non-specific vaccines are not exclusionary but should be discussed with study PI or designee.  Conditions of interest:  We note that international reports of VITT have not identified a risk factor, nor does there appear to be any prothrombotic state that indicates a risk factor for this immune response.  Nevertheless, the Sisonke study will enrol participants with chronic history of severe clotting disorders only after consultation and approval of the study Protocol Safety Review Team (PSRT).  We have identified certain specific conditions of special interest such as:  cerebral venous sinus thrombosis, antiphospholipid syndrome Individuals on therapeutic anticoagulants for current or previous arterial or venous thrombosis or embolism