A Clinical Study to Assess the Safety and Feasibility of Controlled Blood-stage Plasmodium Vivax Human Malaria Infection Through Experimental Inoculation of Cryopreserved Infected Erythrocytes in Healthy Thai Adults
The primary objectives of this study are to assess the safety and feasibility of blood-stage controlled human P. vivax malaria infection (CHMI) in healthy adult Thai volunteers through experimental injection of cryopreserved P. vivax infected erythrocytes, and to choose the optimal inoculation dose for future P. vivax CHMI studies. In this study, blood-stage CHMI will be conducted in 8 volunteers per inoculum stock who will each be infected with P. vivax by experimental injection with cryopreserved P. vivax infected erythrocytes, which were collected from the controlled human Plasmodium vivax malaria infection model through experimental sporozoite infection in Thai adults (NCT04083508) . There are currently 4 stocks of inocula from 6 volunteers in the NCT04083508 study, which have differing quantities and stages of parasites. The total number of volunteers of this study will be up to 48 (8 volunteers per inocula stock). The volunteers will be monitored closely as in-patients in the Hospital for Tropical Diseases, and will be treated according to the Research Proposal. This study is funded by the UK Wellcome Trust. The grant reference number are Oxford/MORU: 212336/Z/18/Z and 212336/Z/18/A, and Mahidol University: 212336/A/18/Z and 212336/A/18/A.
‣ The volunteer must meet all of the following criteria to be eligible for the study:
• Healthy Thai adult aged 20 to 55 years with weight at least 50 kg.
• Red blood cells positive for the Duffy antigen/chemokine receptor (DARC)
• Women only: Must practice continuous effective contraception for the duration of study period until 3 months post-challenge.
• COVID-19 vaccination at least two doses of COVID-19 vaccines approved by WHO.
• Agreement to refrain from blood donation during the course of the study and for 1 year after the initiation of antimalarial treatment.
• Willing to be admitted in the Hospital for Tropical Diseases for clinical monitoring, until antimalarial treatment is completed and their symptoms are settling.
• Willing to take a curative antimalarial treatment following CHMI.
• Willing to reside in Bangkok and its vicinity for 2 months after malarial treatment initiation.
• Able to read and write in Thai.
⁃ Provide written informed consent to participate in the trial
⁃ Answer all questions on the informed consent quiz correctly
⁃ Educational level: has at least an undergraduate degree