Safety, Immunogenicity and Efficacy of the Blood-stage Plasmodium Vivax Malaria Vaccine Candidate PvDBPII in Matrix M1

Inclusion Criteria

• Healthy adult aged 18 to 45 years.
• Red blood cells positive for the Duffy antigen/chemokine receptor (DARC).
• Normal serum levels of Glucose-6-phosphate dehydrogenase (G6PD).
• Negative haemoglobinopathy screen
• Able and willing (in the Investigator's opinion) to comply with all study requirements.
• Willing to allow the Investigators to discuss the volunteer's medical history with their General Practitioner.
• Women only: Must practice continuous highly effective contraception* for the duration of the study
• Agreement to permanently refrain from blood donation
• Written informed consent to participate in the trial.
• Reachable (24/7) by mobile phone during the period between CHMI and completion of all antimalarial treatment.
• Willing to take a curative anti-malarial regimen following CHMI.
• Willing to reside in Oxford for the post-challenge period, until antimalarials have been completed.
• Answer all questions on the informed consent quiz correctly at first or second attempt
• Female volunteers are required to use a highly effective form of contraception during the course of the study as malaria challenge could pose a serious risk to both maternal health and the unborn foetus.

Exclusion Criteria

• History of clinical malaria (any species).
• Travel to a clearly malaria endemic locality during the study period or within the preceding six months.
• Use of systemic antibiotics with known antimalarial activity within 30 days of CHMI (e.g. trimethoprim-sulfamethoxazole, doxycycline, tetracycline, clindamycin, erythromycin, fluoroquinolones and azithromycin).
• Use of anti-malarials within 30 days of CHMI
• Weight less than 50kg, as measured at the screening visit
• Receipt of immunoglobulins within the three months prior to planned administration of the vaccine candidate.
• Receipt of blood products (e.g., blood transfusion) at any time in the past.
• Peripheral venous access unlikely to allow twice daily blood testing (as determined by the Investigator).
• Receipt of an investigational product in the 30 days preceding enrolment, or planned receipt during the study period.
• Receipt of any vaccine in the 30 days preceding enrolment, or planned receipt of any other vaccine within 30 days preceding or following each study vaccination, with the exception of licensed COVID-19 vaccines, which should not be received between 14 days before to 7 days after any study vaccination
• Planned receipt of a COVID-19 vaccine between 2 weeks before the day of CHMI until completion of antimalarial treatment
• Concurrent involvement in another clinical trial or planned involvement during the study period
• Prior receipt of an investigational vaccine likely to impact on interpretation of the trial data or the P. vivax parasite as assessed by the Investigator.
• 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).
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine e.g. egg products, Kathon
• History of allergic disease or reactions likely to be exacerbated by malaria infection.
• History of clinically significant contact dermatitis
• Any history of anaphylaxis in reaction to vaccinations
• Pregnancy, lactation or intention to become pregnant during the study.
• Use of medications known to cause prolongation of the QT interval and existing contraindication to the use of Malarone.
• Use of medications known to have a potentially clinically significant interaction with Riamet and Malarone.
• Any clinical condition known to prolong the QT interval.
• History of cardiac arrhythmia, including clinically relevant bradycardia.
• Disturbances of electrolyte balance, e.g. hypokalaemia or hypomagnesaemia.
• Family history of congenital QT prolongation or sudden death.
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