Investigating COVID-19 Vaccine Immunity in Children in the Melbourne Infant Study of BCG for Allergy and Infection Reduction

Inclusion Criteria: * Age between five and eleven years (i.e. prior to the twelfth birthday) at the time of enrolment, * Participant who was randomised in the MIS BAIR trial, and * Was randomly allocated to receive and received BCG as part of the MIS BAIR trial, OR, * Was randomly allocated to not receive and did not receive BCG; * Is an individual whose parent/legally acceptable representative (LAR) consented to be contacted about future ethically approved research, during the MIS BAIR trial consent process, AND * Has a parent/LAR capable of understanding the parent/LAR information statement and consent form (PICF) document and providing consent on the participant's behalf. Exclusion Criteria: * Has a known hypersensitivity to the active ingredient or any of the excipients in tozinameran, * Has a prior polymerase chain reaction (PCR)-confirmed diagnosis of COVID-19 whether symptomatic or not, * Has received a COVID-19 vaccine (approved by the TGA or otherwise) prior to trial enrolment, * An individual and/or parent/legally acceptable representative who is unwilling or unable to give written informed consent, * An individual and/or parent/legally acceptable representative who is unwilling or unable to consent to attend all scheduled study visits, * An individual and/or parent/LAR who is unwilling or unable to give consent for blood samples to be taken from the trial participant at each study visit, and * Has or has had a clinically significant medical morbidity (e.g. …