This includes giving a lower dose of the Pfizer-BioNTech vaccine, or a protein-based vaccine produced by Novavax. A control group will receive a meningitis vaccine (Bexsero, against MenB bacteria) followed by a Pfizer-BioNTech COVID-19 vaccine later in the study. This means participants will not know what third dose vaccine they are receiving until three months after their vaccine dose. They will also examine if a one-third adult dose of the Pfizer-BioNTech vaccine is at least as good as a full child dose of the same vaccine. ‘Thousands of volunteers are still stepping forward for a number of vaccine booster studies, two years on since we began to recruit into the first COVID-19 vaccine studies.
