Safety and Immunogenicity of the Malaria Vaccine, R21/MatrixM, in Healthy Thai Adults

Inclusion Criteria

The participant is eligible to enter the study if all of the following apply:

• Participant is a healthy adult, aged 18 to 55 years (inclusive), of Thai origin.
• Participant is willing and able to give informed consent to participate in the trial
• Able, in the investigator's opinion, and willing to comply with the study requirements and follow-up.
• Women of childbearing potential: must agree to practice continuous, effective contraception for the duration of the trial, and have a negative pregnancy test before each vaccination. (Costs for contraceptives will be reimbursed by the trial.)

Exclusion criteria

The following criteria should be checked at the time of study entry. If ANY exclusion criterion applies, the subject must not be included in the study:

• Pregnancy or breastfeeding, or planned pregnancy during the course of the study.
• Presence of any medical condition (physical or mental) which, may place the participant at undue risk or interfere with the results of the study*. Including: serious cardiac, renal, hepatic or neurological disease, severe malnutrition
• Any confirmed or suspected immunosuppressive or immunodeficient condition. Including: history of splenectomy, human immunodeficiency virus (HIV) infection
• Chronic administration (>14 days in total) of immunosuppressants or other immune-modifying drugs within six months of enrollment. Including: oral corticosteroids equivalent to prednisone > 20 mg/day (a)
• History of an autoimmune disease
• Hepatitis B surface antigen (HBsAg) or Hepatitis C antibody(b) detected in serum.
• Screening electrocardiogram (ECG) demonstrating a QTc interval ≥ 450 ms
• Seropositivity for hepatitis C virus (antibodies to HCV) at screening (b)
• Finding on safety laboratory values as defined below:
• AST > 2 x upper normal limit
• ALT > 2 x upper normal limit
• Anaemia (Hb 2 x upper normal limit
• Abnormalities of examination or investigations at screening. Including: hepatomegaly, right upper quadrant abdominal pain or tenderness, abnormal blood tests (as defined in the protocol which are not listed above)
• Positive malaria parasitaemia (RDT) at screening or baseline (Month 0, Day 0).
• Receipt or planned receipt of an investigational medical product or participation in an interventional clinical trial during the study period
• Contraindications to the use of artemisinins, piperaquine or primaquine*. Including: use of medications with known potential interactions, prior allergic reactions to one or more components of the drug regimen.
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine (e.g. egg products)
• History of clinically significant contact dermatitis.
• Contraindication to intramuscular (IM) injection*
• Administration of a vaccine not included in the study protocol within 30 days of a study vaccine (c).
• History of anaphylaxis post-vaccination.
• Administration of immunoglobulins and/or any blood products during the period starting three months before the first dose of study vaccine or planned administration during the study period.
• subject to the investigator's judgement

Exceptions:

a Inhaled and topical steroids. b Participation in hepatitis C vaccine study with confirmed negative HCV antibodies prior to participation in that study, and negative HCV RNA PCR at screening for this study c The following vaccinations may be administered more than 7 days before or after a study vaccination: polio, diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b, Bacillus Calmette-Guérin (BCG vaccine), measles, influenza, pneumococcal disease, COVID-19 or yellow fever