Sustainable Community Action for Lung hEalth (SCALE): a cluster randomised trial in Blantyre, Malawi

Tuberculosis (TB) is a major cause of death, with South Africa especially affected because of HIV-TB interactions. Options for improving control are limited. The numerous barriers to diagnosing TB mean that it is often undiagnosed and transmission rates remain high. Reducing cases of undiagnosed TB is critical to ongoing efforts to control it.

We will carry out a cluster-randomised trial (CRT) investigating one approach to reduce undiagnosed TB by using six-monthly enquiries for chronic cough, and TB and HIV diagnosis provided at household level. This intervention is supported by four previous studies showing evidence of effectiveness, but with no CRT of sufficient size to estimate its impact on undiagnosed TB. We will recruit community members to assist with the identification of chronic cough and provide supervised HIV self-testing with support of volunteer groups in intervention arm clusters. This is a well-established way of more effectively delivering community-based interventions in Africa and Asia. Primary clinic management of people with suspected TB and infection control will be strengthened in both arms of the study.

The WHO EndTB strategy includes cautious support for community-wide interventions and warns against scale-up of costly interventions without unequivocal evidence of effect. This study could provide evidence that this inexpensive intervention is effective at identifying undiagnosed TB.