R21/MM Dosing, Presentations, and Preservatives

This is a single blind randomised controlled trial (Phase 3 trial). This study aims to assess whether a half-dose of the R21/Matrix-M malaria vaccine is as effective as the full dose in children and adults. The results will help optimize vaccine usage and improve malaria prevention strategies. All participants will receive the same number of injections and will be randomly assigned to receive one of the followings: * Group 1: Adults and adolescents receiving the standard adult vaccine dose: 10μg R21/50μg Matrix-M (n=125). * Group 2: Adults and adolescents receiving a half of the standard adult vaccine dose: 5μg R21/50μg Matrix-M: 10 dose vials with adaptor Preservative Free (n=125) * Group 3: Adults and adolescents receiving a half of the standard adult vaccine dose: 5μg R21/50μg Matrix-M: 10 dose vials with 2PE Preservative (n=125) Clinical procedure for participants: * Standardized symptom questionnaire * Physical examination: Weight, height, pulse, blood pressure, respiratory rate, tympanic temperature. Spleen and liver size will be recorded if palpable. Pregnancy test (for female of child bearing potential) * Venous blood collection (Pre-vaccination) 3mL * Vaccination