Vivax Malaria Human Infection Studies in Thailand

NCT04083508 | Recruiting DMC

• 1 other identifier: MAL19002
• Study Type: interventional
• Target: 6
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Plasmodium Vivax Infection

Outcome Measures

Primary Outcomes (3)

• Successful infection of controlled P. vivax sporozoite human challenge

  Measured by successful infection (development of detectable persistent parasitaemia) and malaria clinical symptoms, if any, after mosquito bite malaria sporozoite challenge

  up to 21 days after challenge

• (Serious) Adverse Event(s) occurrences of controlled P. vivax sporozoite human challenge

  Measured by (S)AE(s) occurrences after mosquito bite malaria sporozoite challenge.

  up to 90 days after challenge

• Collection and freezing down of up to 250 mL P. vivax-infected blood from each of the 6 volunteers.

  measured by successful collection and freezing down of up to 250 mL P. vivax-infected blood from each of the 6 volunteers.

  up to 21 days after challenge

Secondary Outcomes (3)

• Cellular Immune response to primary P. vivax infection.

  up to 1 year after challenge

• Humoral Immune response to primary P. vivax infection.

  up to 1 year after challenge

• Gametocytaemia following primary P. vivax infection delivered by the mosquito bite

  up to 1 year after challenge

Study Arms (1)

Malaria challenge

EXPERIMENTAL

Malaria Sporozoite Challenge by mosquito bites.

Other: Mosquito bites

Interventions

Mosquito bites OTHER

Successful feeding of 5 infected P. vivax mosquitoes

Malaria challenge

Eligibility Criteria

• Age: 20 Years - 55 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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.
• COVID-19 vaccination at least two doses of COVID-19 vaccine(s) approved by WHO.
• Agree to practice continuous effective contraception for the duration of study period until 3 months post-challenge.
• Agreement to refrain from blood donation during the course of the study and for 1 year after the end of their involvement in the study.
• Willing to take a curative antimalarial regimen following challenge.
• Willing to be admitted in the Hospital for Tropical Diseases for blood donation and clinical monitoring, until antimalarial treatment is completed and their symptoms are settling.
• Willing to reside in Bangkok for the duration of the study, until all antimalarial treatment has been completed.
• Reachable (24/7) by mobile phone during the period between challenge CHMI and completion of all antimalarial treatment.
• Able to read and write in Thai and able to answer ALL questions on the informed consent questionnaire correctly.
• Provided written informed consent to participate in the trial.
• Educational level: has at least an undergraduate degree.

You may not qualify if:

• History of clinical malaria.
• Positive malaria PCR OR malaria film OR malaria serology (recent exposure)
• History of severe allergy to mosquito bite
• Presence of any medical condition (either physical or psychological) which in the judgment of the investigator would place the participant at undue risk or interfere with the results of the study (e.g. serious underlying cardiac, renal, hepatic or neurological disease; severe malnutrition; congenital defects or febrile condition)
• Presence of chronic disease or chronically use of medication.
• Plan to travel outside of Bangkok within the period of challenge until 3 months after.
• Use of systemic antibiotics with known antimalarial activity in the 30 days before challenge (e.g. trimethoprim-sulfamethoxazole, doxycycline, tetracycline, clindamycin, erythromycin, fluoroquinolones and azithromycin).
• Use of immunoglobulins or blood products (e.g. blood transfusion) at any time in the 1 year preceding enrolment.
• Venipuncture unlikely to allow blood donation according to the protocol as determined by the investigator.
• Receipt of an investigational product or any vaccine in the 30 days preceding enrolment (D0), or planned receipt 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, history of splenectomy, recurrent, severe infections, and chronic infection.
• Immunosuppressant medication within the past 6 months preceding enrolment (D0) (inhaled and topical steroids are allowed).
• History of allergic disease or reactions likely to be exacerbated by malaria infection.
• Female participant who is pregnant, lactating or planning pregnancy during the course of the study.

Sponsors & Collaborators

• University of Oxford: lead
• Mahidol University: collaborator

Study Sites (1)

Faculty of Tropical Medicine

Bangkok, 10400, Thailand

RECRUITING

Related Publications (1)

• Naemiratch B, Kulpijit N, Ruangkajorn S, Day NPJ, Prachumsri J, Cheah PY. Experiences, perceptions and ethical considerations of the malaria infection study in Thailand. BMC Med Ethics. 2025 Jan 28;26(1):14. doi: 10.1186/s12910-024-01160-7.

  PMID: 39875955 DERIVED

Study Officials

• Nicholas Day, MD

  University of Oxford

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Nicholas Day, MD

CONTACT

+66-(0)2-3549170; nickd@tropmedres.ac

Jetsumon Sattabongkot Prachumsri, Ph.D

CONTACT

+66-(0)2-3549100; jetsumon.pra@mahidol.ac.th

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: OTHER
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Mosquito-bite controlled human challenge infection

Study Record Dates

• First Submitted: September 5, 2019
• First Posted: September 10, 2019
• Study Start: October 5, 2020
• Primary Completion: April 30, 2026
• Study Completion: April 30, 2026
• Last Updated: January 12, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will share
• Time Frame: After completion of trial activities and reporting

Locations

TH (1)