XACT-3 TB Trial
A randomised controlled trial evaluating scalable active case finding for tuberculosis using point-of-care molecular diagnostics (GeneXpert).
XACT-3 is a multi-country randomised controlled trial of a scalable active case-finding intervention for tuberculosis, using a point-of-care molecular test (GeneXpert). The consortium principal investigator is Professor Keertan Dheda. BRTI runs the Harare site. Study updates are published at xact3.co.za.
Background
The reservoir of tuberculosis transmission remains concentrated in large peri-urban settlements in Africa and Asia. Many infectious cases have few symptoms. People often wait until they feel very ill before seeking diagnosis and treatment, and the community stays at risk in the meantime. Actively looking for tuberculosis, including in people with minimal symptoms, can interrupt transmission and start treatment sooner. Active case finding still needs to be optimised. That is what this study is designed to do.
Study aims
- Evaluate a scalable active case-finding intervention using GeneXpert at the point of care.
- Describe the bio-phenotype of microbiologically confirmed but minimally symptomatic tuberculosis found through active case finding.
- Model the cost-effectiveness of active case finding with Xpert at the point of care, compared with centralised laboratories.
Outcome measures
Primary. The proportion of people who test positive and are lost to follow-up before treatment, defined as failure to start treatment by 60 days, and the proportion of infectious patients (smear-positive or with cavitary lung disease) who have not started treatment within 14 days of diagnosis.
Secondary. Time to treatment initiation, whether minimally trained health workers can perform Xpert at the point of care, and turnaround time for Xpert testing in both arms.
Economic. Cost-effectiveness of an active case-finding strategy using Xpert Ultra at the point of care versus centralised laboratories, including the effect on drug-resistant tuberculosis transmission and on HIV prevention.
Harare site team
- Dr Shungu Munyati, Director General
- Dr J. Mutsvangwa, Zimbabwe site principal investigator
- Ashley Nyaradzai Chizema, study coordinator
- Caroline Maposhere, advocacy, communication, and social mobilisation
- Joachim Sadziwa, monitoring and evaluation
- Shylock Chirimumvura, research nurse
- Beauty Makamure, laboratory manager
- Dr Shepherd Shamu, health economist
- Tsitsi Bandason, biostatistician