Scrub Typhus Antibiotic Resistance Trial

NCT ID: NCT03083197

Last Updated: 2026-01-12

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.

Recruitment Status

RECRUITING

Clinical Phase

PHASE4

Total Enrollment

177 participants

Study Classification

INTERVENTIONAL

Study Start Date

2017-10-15

Study Completion Date

2026-10-31

Brief Summary

Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.

Study type: Randomized Control Treatment Trial

Study population: Male and female patients with ≥15 years of age and acute scrub typhus

Duration: 2 years

Study Design: Prospective, open-label, randomized-controlled treatment trial in patients ≥15 years old admitted to hospital with acute scrub typhus. Randomization into 3 oral treatment arms (each n=59 patients, total n=177): i) 7 days of doxycycline, ii) 3 days of doxycycline, and iii) 3 days of azithromycin

Primary Objective: To evaluate the clinical and microbiological responses in scrub typhus patients to three oral treatment regimens: 7 days of doxycycline, 3 days of doxycycline, and 3 days of azithromycin

Secondary Objectives:

1. To perform pharmacokinetic/pharmacodynamics (PK/PD) characterization of the therapeutic responses for doxycycline and azithromycin, incl. serial bacterial load measurements.
2. To define clinical, bacterial, pathophysiological and pharmacological factors associated with disease severity, fever-clearance times (FCT), treatment failures and relapse/re-infection.
3. To determine the minimum inhibitory concentrations (MIC) of clinical Orientia tsutsugamushi isolates to doxycycline, azithromycin and chloramphenicol, using in vitro growth-inhibition assays
4. To genotype all clinical isolates using whole genome sequencing for comparative genomics.
5. To dissect the natural immune response in scrub typhus, using antigen-specific cellular immune and antibody studies, and cytokine profiling

Detailed Description

Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.

The funder is USAMRMC - MIDRP and Grant No. DHP-Award D6.7\_15\_C2\_I\_15\_J9\_1317

Conditions

See the medical conditions and disease areas that this research is targeting or investigating.

Scrub Typhus

Study Design

Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.

Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

Review each arm or cohort in the study, along with the interventions and objectives associated with them.

Doxycycline 7 days

loading dose 200mg PO, then 100mg PO every 12 hours for 7 days

Group Type ACTIVE_COMPARATOR

Doxycycline 7 days

Intervention Type DRUG

loading dose 200mg PO, then 100mg PO every 12 hours for 7 days

Doxycycline 3 days

loading dose 200mg PO, then 100mg PO every 12 hours for 3 days

Group Type ACTIVE_COMPARATOR

Doxycycline 3 days

Intervention Type DRUG

loading dose 200mg PO, then 100mg PO every 12 hours for 3 days

Azithromycin 3 days

loading dose 1000mg PO on day 1, then 500mg PO every 24 hours on days 2 and 3

Group Type ACTIVE_COMPARATOR

Azithromycin 3 days

Intervention Type DRUG

loading dose 1000mg PO on day 1, then 500mg PO every 24 hours on days 2 and 3

Interventions

Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.

Doxycycline 7 days

loading dose 200mg PO, then 100mg PO every 12 hours for 7 days

Intervention Type DRUG

Doxycycline 3 days

loading dose 200mg PO, then 100mg PO every 12 hours for 3 days

Intervention Type DRUG

Azithromycin 3 days

loading dose 1000mg PO on day 1, then 500mg PO every 24 hours on days 2 and 3

Intervention Type DRUG

Eligibility Criteria

Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.

Inclusion Criteria

* Age ≥ 15 years old
* Hospitalization with acute undifferentiated fever (temperature \> 37.5°C, tympanic) ≤14 days or patients admitted to hospital with a history of fever ≤ 14 days who subsequently develop fever within 24 hours of admission
* Clinically suspected scrub typhus: defined as acute undifferentiated fever with no clear focus of infection and negative malaria blood smear and/or negative malaria RDT. Patients may have one, none, or a combination of other clinical findings such as eschar, rash, lymphadenopathy, headache, myalgia, cough, nausea and abdominal discomfort.
* A positive scrub typhus RDT (Scrub Typhus IgM RDT, InBios International, Seattle, WA, USA) and/or positive PCR-based detection of O. tsutsugamushi DNA from the admission blood sample
* Written informed consent and/or, written informed assent as required
* Able to take oral medication

Exclusion Criteria

* Known hypersensitivity to tetracycline, doxycycline or azithromycin
* Administration of doxycycline, azithromycin, chloramphenicol, rifampicin, or tetracycline during the preceding 7 days
* Pregnancy or breast-feeding
* Patients with myasthenia gravis or systemic lupus erythematosus
* Patients with an established infection (diagnostic test required) e.g. acute malaria, dengue, leptospirosis, typhoid, Japanese encephalitis etc.
* Current TB or TB treatment in ≤ 6 months (contain active antibiotics against Orientia spp.)
* Current HAART use for HIV, long term use of immunosuppressants (e.g. steroids, chemotherapy, TNF-inhibitors and related agents)
* Patients with severe disease whom the clinical team feel their condition necessitates the need for additional scrub typhus treatment beyond the allocated antibiotic treatment assigned at randomization (e.g. IV chloramphenicol and/or PO/NG rifampicin)
Minimum Eligible Age

15 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

Meet the organizations funding or collaborating on the study and learn about their roles.

Shoklo Malaria Research Unit

OTHER

Sponsor Role collaborator

Chiangrai Prachanukroh Hospital

OTHER

Sponsor Role collaborator

University of Oxford

OTHER

Sponsor Role lead

Responsible Party

Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.

Responsibility Role SPONSOR

Principal Investigators

Learn about the lead researchers overseeing the trial and their institutional affiliations.

Assoc. Prof. Daniel Paris

Role: PRINCIPAL_INVESTIGATOR

Mahidol-Oxford Tropical Medicine Research Unit, Bangkok, Thailand

Locations

Explore where the study is taking place and check the recruitment status at each participating site.

Shoklo-Malaria Research Unit (SMRU)

Mae Sot, Changwat Tak, Thailand

Site Status NOT_YET_RECRUITING

Chiangrai Prachanukroh Hospital

Chiang Rai, , Thailand

Site Status RECRUITING

Countries

Review the countries where the study has at least one active or historical site.

Thailand

Central Contacts

Reach out to these primary contacts for questions about participation or study logistics.

Assoc. Prof. Daniel Paris

Role: CONTACT

+6622036373

Tri Wangrangsimakul

Role: CONTACT

+6622036333

Facility Contacts

Find local site contact details for specific facilities participating in the trial.

Rose McGready, Prof

Role: primary

Tri Wangrangsimakul, MD

Role: primary

Other Identifiers

Review additional registry numbers or institutional identifiers associated with this trial.

START

Identifier Type: -

Identifier Source: org_study_id

More Related Trials

Additional clinical trials that may be relevant based on similarity analysis.

Scrub Typhus RDT Study
NCT03269266 COMPLETED
Azithromycin for Meningococcal Carriage
NCT06618534 RECRUITING PHASE2