There will be a total of 800 participants in the study, to be randomised and administered booster doses in this study.~The study will be conducted at 3 clinics in Bandung. Participants will have previously received primary doses of Coronavac or Astranzeneca, with the second dose administered at least 6 months previously.~Participants will be followed for 12 months following the booster vaccine adminstration, with blood samples drawn at baseline, 28 days, 6 months and 12 months following booster vaccine administration.
This is a randomised controlled clinical trial to determine the reactogenicity and immunogenicity of booster doses of SARS-CoV-2 vaccines (Pfizer-BioNTech, AstraZeneca or Moderna) in adults who have previously received either AstraZeneca or Coronavac as their primary doses.~Both fractional and standard doses of Pfizer-BioNTech, AstraZeneca and Moderna will be tested.