RecruitingNot Applicable

Clinical Study to Assess Minimum Mosquito Bites for P. Vivax Infection in Thai Adults

Thailand24 participantsStarted 2026-02-02

Plain-language summary

This study is a human challenge study to assess the minimum infective mosquito bite dose in a controlled human malaria Infection (via P. vivax sporozites) in healthy volunteers. The results will inform the development of a P. vivax mosquito-delivered CHMI trial platform, supporting safer and more accurate vaccine efficacy assessments. Conducting the trial in individuals genetically and immunologically similar to the target population will also enhance the relevance of findings to real-world endemic settings. 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.

Who can participate

Age range

20 Years – 55 Years

Sex

ALL

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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

. Healthy adult aged 20 to 55 years with weight more than 50 kg.
. No recent malaria infection.
. Red blood cells positive for the Duffy antigen/chemokine receptor (DARC).
. CYP2D6 alleles consistent with normal metaboliser status.
. Normal level of Glucose-6-phosphate dehydrogenase (G6PD) enzyme activity by the WHO definition.
. Women only: Must 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.

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

The minimum number of infected mosquito bites.

Timeframe: Up to 21 days after the individual CHMI

Trial details

NCT IDNCT07257965

SponsorUniversity of Oxford

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2027-08-31

Contact for this trial

Nicholas Day, MD

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

View on ClinicalTrials.gov More Plasmodium Vivax Infection trials