Due to significant delays in receiving local regulatory approval to extend the shelf-life of the IMP.

A phase Ib age de-escalation and dose escalation open label clinical trial of the safety, immunogenicity and ex-vivo efficacy of a candidate malaria vaccine Pfs25-IMX313/Matrix-M administered intramuscularly in healthy adults and young children in Tanzania

This study aims to evaluate safety, immunogenicity, and transmission blocking activity of Pfs25IMX313-Matrix-M in healthy Tanzanian adults and children naturally exposed to malaria in Bagamoyo district, Tanzania. The study will enrol 45 volunteers comprising of 13 adults (18-45 years) and 32 children (5-12 years).

Inclusion Criteria:

1. Healthy adult aged 18 to 45 years or children aged 5-12 years.
2. Planned long-term (at least 30 months from the date of recruitment) or permanent residence in Bagamoyo town.
3. Adults with a Body Mass Index (BMI) 18 to 30 Kg/m2; or children (5-12 years) with the BMI between 13 and 25 Kg/m2.
4. Able and willing (in the Investigator's opinion) to comply with all study requirements.
5. Agreement to refrain from blood donation for the duration of the study
6. Written informed consent to participate in the trial.
7. Women only: Must practice continuous effective contraception* for the duration of the study.

Exclusion Criteria:

1. Use of immunoglobulins or blood products (e.g., blood transfusion) at any time in the past.
2. Receipt of any vaccine in the 14 days preceding enrolment, or planned receipt of any other vaccine within 14 days following each vaccination.
3. Receipt of an investigational product in the 30 days preceding enrolment, or planned receipt during the study period.
4. Concurrent involvement in another clinical trial or planned involvement during the study period
5. Prior receipt of an investigational vaccine likely to impact on interpretation of the trial data, as assessed by the Investigator
6. Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV infection; asplenia; recurrent, severe infections and chronic (more than 14 days) immunosuppressant medication within the past 6 months (inhaled and topical steroids are allowed).
7. History of allergic disease or reactions likely to be exacerbated by any component of the vaccine (e.g. egg products)
8. Any history of anaphylaxis in reaction to vaccinations
9. Pregnancy, lactation or intention to become pregnant during the study.
10. History of cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ).
11. History of serious psychiatric condition that may affect participation in the study.
12. Any other serious chronic illness requiring hospital specialist supervision.
13. Suspected or known injecting drug abuse in the 5 years preceding enrolment.
14. Seropositive for hepatitis B surface antigen (HBsAg) or hepatitis C (HCV IgG).
15. Volunteers unable to be closely followed for social, geographic or psychological reasons.
16. Any clinically significant abnormal finding on biochemistry or haematology blood tests, urinalysis or clinical examination. In the event of clinically significant abnormal test results, confirmatory repeat tests will be requested. Procedures for identifying laboratory values meeting exclusion criteria will be described in a study specific SOP.
17. 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.