A randomised trial to evaluate the immune response of COVID-19 vaccines in adults and adolescents

The PICOBOO study is an ongoing Australian trial designed to figure out the best strategies for COVID-19 booster vaccinations. As new variants emerge and new vaccine formulations become available, this trial is designed to adapt and keep answering the most current questions. Rather than testing a single new vaccine, it compares different booster combinations to understand which offers the best immune response with the least side effects. Participants give blood and saliva samples at set intervals so researchers can measure how well different booster strategies stimulate the immune system. This ongoing approach means the trial can stay relevant as the pandemic situation changes, giving Australian health authorities the best evidence to guide national vaccine policy. You may be eligible if you are 12 years of age or older, have already completed a primary COVID-19 vaccination series (specific eligibility depends on which vaccine you received and your age), and are registered on the Australian Immunisation Register. People who have received a booster in the last 3 months, those with severe immune system problems, or those with a history of serious allergic reactions to vaccine components are not eligible.