NCT04083508

Vivax Malaria Human Infection Studies in Thailand

A Clinical Study to Assess the Feasibility of a Controlled Human Plasmodium Vivax Malaria Infection Model Through Sporozoite Infection in Thai Adults

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 6 (estimated)
• Sponsor: University of Oxford · Academic / Other
• Sex: All
• Age: 20 Years – 55 Years
• Healthy volunteers: Accepted

Summary

This study is a human challenge study to assess the feasibility and safety of controlled human malaria infection (via P. vivax sporozites) in healthy volunteers, and to develop a bank of P. vivax-infected blood for use in future controlled human P. vivax malaria infection studies. Additional objectives are to obtain data on host immune response to P. vivax infection and pre-treatment gametocytaemia. 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.

Detailed description

Six healthy, malaria-naïve Thai adults, aged between 20 and 55 years will be recruited at the Medical Therapeutics Unit (MTU) in the Hospital for Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok. The overall period of participation will be 15 months: a 3-month screening process prior to the Day 0 challenge, followed by 1 year after challenge. All inclusion and exclusion criteria will be checked to ensure eligibility criteria have been met prior to Day 0. Volunteers will be admitted as inpatients to the CTU on Day -1 ( a day prior to the challenge day). Challenge (bites from 5 infected mosquitoes) will be administered at the Insectarium unit, Department of Entomology, Faculty of Tropical Medicine, Mahidol University. The infected mosquitoes will be prepared by the Malaria Vivax Research unit (MVRU, Faculty of Tropical Medicine, Mahidol University). Following successful feeding by the infectious mosquitoes, volunteers will be monitored daily as inpatients for parasitemia and clinical presentation of malaria infection (Days 1-5). Beginning on Day 6, volunteers will be assessed twice a day and, at a timepoint that will depend upon the level of parasitaemia and/or degree of the volunteer's symptoms, up to 250 mL of blood will be drawn and then antimalarial treatment will be prescribed. The standard malaria radical cure according to standardguideline will be chloroquine, followed by direct observed of oral primaquine (PQ) 30 mg once daily until a total dose of 10 mg/kg is achieved. Upon confirmation of clinical recovery, completion of chloroquine treatment and laboratory absence of infection, volunteers will be discharged and followed daily as outpatients through completion of oral primoquine therapy. After completion of antimalarial therapy, all volunteers will continue to be followed for 1 year after Day 0: * Outpatient CTU visits on Days 28,60, 90, 180, and 365 post-challenge. Procedures to be performed during these visits will include review of symptom diary cards, medical history, physical examination and assessment of adverse events. Blood samples will also be obtained to detect malaria antigens and assess immune response. * Volunteers will be contacted by study staff every 2 weeks between visits until Day 365, to inquire for malaria symptoms or other adverse events.

Conditions

• Plasmodium Vivax Infection

Interventions

Type	Name	Description
OTHER	Mosquito bites	Successful feeding of 5 infected P. vivax mosquitoes

Timeline

• Start date: 2020-10-05
• Primary completion: 2026-04-30
• Completion: 2026-04-30
• First posted: 2019-09-10
• Last updated: 2026-01-12

Locations

1 site across 1 country: Thailand