PLASMODIUM FALCIPARUM MALARIA

The AVERT study is a prospective observational test-negative case control study evaluating the real-world effectiveness of the R21/Matrix-M malaria vaccine among children younger than 5 years in Burkina Faso and Uganda. Children who seek outpatient care with suspected malaria and are eligible for the national R21/Matrix-M vaccination program will be enrolled. Malaria infection will be determined by blood smear microscopy. Children with a positive microscopy result will be classified as cases and children with a negative result as controls. Vaccination history, including the number and timing of doses, will be obtained primarily from vaccination cards or other written records. Vaccine effectiveness will be estimated by comparing the odds of vaccination among cases and controls.

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

This is an open i.e. not blinded, cluster-randomised, controlled intervention study. The study will use a factorial design to estimate the protective effectiveness of mass drug administrations, mass vaccinations, combined mass vaccinations and drug administrations versus the current standard of care.