This is a study in which healthy adult volunteers will be given either an experimental Malaria vaccine or a saline control vaccine.

Each volunteer will receive three vaccinations in total. Volunteers will be randomly allocated to one of two groups:

Group 1 will receive a low dose of the Malaria vaccine on days 0, 28, and 56. Group 2 will receive a saline solution on days 0, 28, and 56.

A randomised, controlled, single-blind clinical trial to evaluate the safety and immunogenicity of the malaria vaccine candidate regime of three (3) doses of R21/Matrix-M1 compared with placebo, in healthy West African adult volunteers living in a malaria-endemic area.

The study will take place at the Centre National de Recherche et de Formation sur la Paludisme (CNRFP)/Unite de Recherche Clinique de Banfora (URC-B). Trial participants will be drawn from the Banfora Health Demographic system, which covers a total population of 30, 000.

Community sensitisation will be undertaken to engage the community with the study and recruit volunteers for participation in the study. The CNRFP study team will hold local community meetings and explain the study to the potentially eligible adult volunteers. During these meetings the investigators will explain the following: the need for a vaccine; the current status of vaccine development (including the fact that this is likely to be a prolonged process); the study screening and informed consent procedure; risks of vaccination and the unproven benefits of vaccination. It will be stressed that these are experimental vaccine regimens and cannot be guaranteed to provide protection, and that it will therefore still be necessary to seek treatment for possible malaria even after vaccination and they should continue to use other protective measures such as bed nets. It will be explained that to aid identification, a photograph of the volunteer will be taken if they are eligible to be enrolled in the trial.

After this meeting, based on the list of adults of suitable age for participation in the trial drawn from the DSS database, volunteers will be asked to participate in a public lottery that is made to randomly select participants who will be invited for a screening visit. All proposed volunteers thus selected will be invited to the Banfora clinical trials centre for the screening visit.

The Volunteer Information Sheet (VIS) will contain detailed information about the study and will be distributed to the proposed volunteers. The investigators will endeavour to ensure that all volunteers fully understand the risks. Any volunteer who appears to have less than complete understanding will be considered unable to give consent. If unable to sign, the volunteer will be asked to thumbprint the consent form in the presence of an impartial witness who will be present during the screening procedures and will countersign the consent form. Fully consented volunteers will undergo the full screening procedures. This consists of medical history, physical examination, and blood sampling for screening tests.

Volunteers will be randomised to receive either three (3) doses of R21/ Matrix-M1 or placebo (normal saline) as control. Simple randomisation into the study groups will be done by an independent statistician based at the University of Oxford. A randomisation code list will be generated by the independent statistician and its use guided by a clear Standard Operating Procedure (SOP). Allocation concealment will be employed by use of opaque sealed envelopes. As this is a single-blind clinical trial design, the laboratory scientists will be blinded to vaccine allocation until the end of the study.

Each volunteer will be monitored for one hour (or longer if necessary) after each vaccination. Each volunteer will be visited at home daily for 6 days after each vaccination (Days 0, 28, and 56) by a field worker for assessment and recording of any solicited and unsolicited AEs in diary cards. If necessary the volunteer will continue to be seen regularly until any observed AEs have resolved or stabilised. Scheduled visits at the CNRFP will be on Days 0, 7, 28, 35, 56, 63, 84, and 140. All volunteers will be followed up to Day 140 post-first vaccination for adverse events.

Inclusion Criteria:

The volunteer must satisfy all the following criteria to be eligible for the study:

• Healthy adults ages 18 to 45 years.
• Willingness to remain in study area for the period of the study.
• Able and willing (in the Investigator's opinion) to comply with all study requirements.
• Women only: Must practice and show documented evidence of continuous effective contraception (e.g. depo-progesterone) or must be willing to take contraceptive measures not to become pregnant for the duration of the study. Willing to have pregnancy tests at screening and vaccination time points.
• Agreement to refrain from blood donation during the course of the study.
• Written informed consent to participate in the trial.

Exclusion Criteria:

The volunteer may not enter the study if any of the following apply:

• Hb less than 10.0g/dl
• Receipt of an investigational product in the 30 days preceding enrolment, or planned receipt during the study period.
• Prior receipt of an investigational malaria vaccine or any other investigational vaccine likely to impact on interpretation of the trial data.
• Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV infection; asplenia; recurrent severe infections and chronic (more than 14 days) immunosuppressant or other immune-modifying drugs medication (for corticosteroids, this will mean prednisolone, or equivalent, ≥ 0.5mg/kg/day) within the past 6 months (inhaled and topical steroids are allowed).
• Use of immunoglobulins or blood products within 3 months prior to enrolment.
• History of allergic disease or hypersensitivity reactions likely to be exacerbated by any component of the study vaccines.
• Any history of anaphylaxis post-vaccination.
• History of clinically significant contact dermititis.
• Pregnancy, lactation or intention to become pregnant during the study.
• Disturbances of electrolyte balance, e.g. hypokalaemia or hypomagnesaemia.
• History of cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ).
• History of serious psychiatric condition that may affect participation in the study.
• History of splenectomy.
• Any other serious chronic illness requiring hospital specialist supervision.
• HIV or Hepatitis B surface antigen seropositivity.
• Volunteers unable to be closely followed for social, geographic or psychological reasons.
• Any clinically significant abnormal finding on biochemistry or haematology blood tests, urinalysis or clinical examination. In the event of abnormal test results, confirmatory repeat test will be requested.
• Any other significant disease, disorder, or finding which may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study or impair interpretation of the study data.

Solicited adverse events will be recorded daily for 7 days post-vaccination Unsolicited AEs of all severities will be recorded from receipt of vaccination through 28 days post-vaccination. After study Day 28, only SAEs or new chronic medical conditions that require ongoing medical management will be recorded through to the last study visit.