[{"arm_notes": "", "treatment_id": null, "treatment_name": "Study participants will be randomly allocated to receive one of the following at visit 1: a fractional dose of Pfizer/Wyeth or AstraZeneca/Fiocruz vaccines; or full dose AstraZeneca/Fiocruz vaccine given at least 4 months (120 days) after two doses of Sinovac/Butantan. Participants; laboratory staff; and clinicians assessing causality will be blinded to the treatment allocation. Randomisation will be performed using a secure internet-based randomisation system ensuring allocation concealment by a member of the local research team. Participants will be allocated in a 1:1:1 ratio.", "treatment_type": "TODO", "pharmacological_treatment": "TODO"}]

[{"arm_notes": "fractional dose", "treatment_id": 1443, "treatment_name": "Bnt162b2+chadox1 ncov-19", "treatment_type": "Rna based vaccine+non replicating viral vector", "pharmacological_treatment": "Vaccine"}, {"arm_notes": "full dose", "treatment_id": 1443, "treatment_name": "Bnt162b2+chadox1 ncov-19", "treatment_type": "Rna based vaccine+non replicating viral vector", "pharmacological_treatment": "Vaccine"}]