Experiences, perceptions and ethical considerations of the malaria infection study in Thailand.
Bhensri Naemiratch, Natinee Kulpijit, Supanat Ruangkajorn...
https://pubmed.ncbi.nlm.nih.gov/39875955Actively Recruiting
Phase Not Applicable
Age: 20Years - 55Years
All Genders
Healthy Volunteers
ID04083508
A Clinical Study to Assess the Feasibility of a Controlled Human Plasmodium Vivax Malaria Infection Model Through Sporozoite Infection in Thai Adults
Led by University of Oxford · Updated on 2026-01-12
6
Participants Needed
1
Research Sites
N/A
Total Duration
On this page
Sponsors
U
University of Oxford
Lead Sponsor
M
Mahidol University
Collaborating Sponsor
AI-Summary
What this Trial Is About
Researchers are evaluating the safety and feasibility of a controlled human malaria infection using Plasmodium vivax sporozoites in healthy Thai adults aged 20 to 55 years. This study aims to develop a bank of P. vivax-infected blood for future research and to collect data on the immune response and gametocytaemia following infection. The study is funded by the UK Wellcome Trust and conducted at Mahidol University in Bangkok. Six healthy volunteers will be admitted to a clinical trial unit where they will receive bites from five infected mosquitoes to introduce the malaria parasite. Participants will be monitored closely as inpatients for the first five days, then twice daily until blood parasitemia and symptoms indicate the need for antimalarial treatment. Treatment will include chloroquine followed by supervised oral primaquine until the full dose is completed. After recovery, participants will be discharged and followed as outpatients until the end of therapy. Participants will be followed for one year after the initial challenge, with outpatient visits at days 28, 60, 90, 180, and 365 post-infection. During these visits, symptom diaries, medical histories, physical exams, and blood samples to assess malaria antigens and immune response will be collected. Study staff will also contact volunteers every two weeks to check for symptoms or adverse events. Primary outcomes include successful malaria infection, safety monitoring, and collection of infected blood samples.
CONDITIONS
Brief Title
Vivax Malaria Human Infection Studies in Thailand
Who Can Participate
Age: 20Years - 55Years
All Genders
Healthy Volunteers
Eligibility Criteria
You may qualify if you...
- Healthy adult aged 20 to 55 years with weight more than 50 kg
- Blood group O
- Red blood cells positive for the Duffy antigen/chemokine receptor (DARC)
- CYP2D6 alleles consistent with normal metaboliser status
- Normal blood levels of Glucose-6-phosphate dehydrogenase (G6PDH) by the WHO definition
- Received at least two doses of WHO-approved COVID-19 vaccine
- Agree to practice continuous effective contraception during the study and for 3 months post-challenge
- Agree to refrain from blood donation during the study and for 1 year after study involvement
- Willing to take curative antimalarial treatment following challenge
- Willing to be admitted for blood donation and monitoring until treatment completion and symptoms settle
- Willing to reside in Bangkok for the study duration until treatment completion
- Reachable by mobile phone 24/7 from challenge to treatment completion
- Able to read and write Thai and answer all informed consent questions correctly
- Provided written informed consent
- Educational level of at least an undergraduate degree
- Low cardiovascular risk (less than 10% risk in next 10 years) according to Thai guidelines
You will not qualify if you...
- History of clinical malaria
- Positive malaria PCR, film, or serology indicating recent exposure
- History of severe allergy to mosquito bites
- Any medical condition posing undue risk or interfering with study results (e.g., serious heart, kidney, liver, neurological disease; severe malnutrition; congenital defects; febrile illness)
- Presence of chronic disease or chronic medication use
- Plans to travel outside Bangkok from challenge until 3 months after
- Use of systemic antibiotics with antimalarial activity in 30 days before challenge
- Use of immunoglobulins or blood products in the year before enrollment
- Venipuncture unlikely to allow required blood donation
- Receipt or planned receipt of investigational products or vaccines impacting study data
- Immunosuppressive or immunodeficient conditions including HIV, splenectomy, recurrent or severe infections
- Use of immunosuppressants in past 6 months (except inhaled/topical steroids)
- History of allergic reactions likely worsened by malaria infection
- Pregnancy, lactation, or planning pregnancy during study
- Contraindications or drug interactions with study antimalarials
- Family history of cardiac disease or congenital QT prolongation
- History or evidence of cardiac arrhythmias or prolonged QT interval
- History or suspicion of alcohol or drug abuse
- Concurrent participation in another clinical study
- Low hemoglobin levels
- Abnormal safety laboratory values including liver enzymes, bilirubin, creatinine, calcium, magnesium, fasting blood sugar
- Thalassemia or hemoglobinopathies
- Positive for blood or vector borne infectious diseases (HIV, HBV, HCV, Dengue, Zika, others)
- Positive COVID-19 test by RT-PCR
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
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Your Study Journey
Screening
Duration - 3 months
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Treatment
Duration - Approximately 3 weeks
Participants are admitted as inpatients and receive the malaria sporozoite challenge via mosquito bites, followed by close inpatient monitoring and antimalarial treatment until clinical recovery and laboratory confirmation of infection clearance.
Daily inpatient visits from Day -1 to Day 5, then twice daily assessments from Day 6 until treatment completion
Follow-up
Duration - 1 year
Participants are followed as outpatients with scheduled visits and regular contacts to monitor health status, collect blood samples, and assess immune response and adverse events for up to 1 year after challenge.
Outpatient visits on Days 28, 60, 90, 180, and 365 post-challenge; phone contacts every 2 weeks between visits until Day 365
Trial Site Locations
Total: 1 location
1
Faculty of Tropical Medicine
Bangkok, Thailand, 10400
Actively Recruiting
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Research Team
N
Nicholas Day, MD
J
Jetsumon Sattabongkot Prachumsri, Ph.D
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
OTHER
Number of Arms
1
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