Asymptomatic TB transmission in Indonesia and South Africa

Plain English summary of protocol

Background and study aims
Tuberculosis (TB) remains one of the leading infectious diseases globally, causing significant morbidity and mortality each year. Despite decades of control efforts, TB continues to pose a major public health challenge, particularly in low- and middle-income countries. Traditionally, TB control strategies have focused on identifying and treating individuals who present with symptoms such as persistent cough, fever, and weight loss. However, emerging evidence indicates that a substantial proportion of people infected with TB bacteria exhibit no symptoms a condition referred to as asymptomatic TB (aTB).
This silent form of TB is particularly concerning because individuals with aTB can still harbor infectious bacteria and contribute to ongoing transmission within communities. The presence of undetected people with TB creates a critical gap in current TB programs, which largely rely on symptom-based screening. As a result, many people with TB remain unidentified, possibly perpetuating the cycle of infection and undermining global TB elimination goals.
The ATTIS study ( Asymptomatic TB Transmission in Indonesia and South Africa) seeks to address this gap by quantifying the role of aTB in TB transmission dynamics. By conducting detailed investigations in households across South Africa and Indonesia, two countries with high TB burdens the study aims to generate robust data on the prevalence, infectiousness, and transmission potential of asymptomatic people with TB. These insights will inform the development of more comprehensive screening strategies that go beyond symptom-based approaches, ensuring earlier detection and treatment.
Understanding and addressing asymptomatic TB is essential for accelerating progress towards global TB targets. Closing this detection gap, especially if people with aTB transmit TB, could significantly reduce TB incidence, prevent new infections, and ultimately save millions of lives worldwide. The findings from ATTIS have the potential to reshape TB control policies and strengthen public health interventions at both national and global levels.

Who can participate?
The study will include adults and adolescents aged 15 years and older living in selected communities in South Africa and Indonesia. In the selected communities, only households with children aged 2 to 14 years will be part of the study, as these children will be tested for TB infection. Pregnant women can participate. All participants must provide informed consent prior to any study procedures. People who cannot understand the study or give consent will not be included. Prisoners and individuals lacking mental capacity will not take part. The goal is to involve a broad range of community members to understand TB transmission in real-life settings.

What does the study involve?
Participants will first be screened in their households. Adults will answer health questions, undergo symptom checks, and provide sputum samples for TB testing. If sputum cannot be collected, a tongue swab may be used. A chest X-ray will also be done for all adults as part of the screening. Children in the household will have blood tests to check for TB infection and may be tested again after 8 to 10 weeks. Some participants will visit clinics for more detailed tests, including blood draws and new diagnostic tools like breath sampling. All results will be shared with participants, and anyone diagnosed with TB will be referred for treatment. Those that are contacts of a person with TB will be referred for TB preventative therapy.

What are the possible risks and benefits of participating?
The study involves minimal risks. Sputum collection is safe but requires precautions to prevent infection spread. Chest X-rays use very low radiation and are considered safe, even for pregnant women with proper shielding. Blood draws may cause slight pain, bruising, or dizziness, but these effects are short-lived. Learning about a new TB or HIV diagnosis can be stressful, so counselling will be provided by the study staff. Strict confidentiality will be maintained to protect personal information. Benefits for participating in the ATTIS study include free TB and HIV screening, early diagnosis, and referral for treatment. Participants also contribute to research that could improve TB control in their communities and globally.

Where is the study being run from?
The study will take place in two countries: South Africa and Indonesia. In South Africa, it will be conducted in KwaZulu-Natal Province, King Cetshwayo and Umkhanyakude districts. In Indonesia, the study will run in Bandung City, West Java Province. These locations were chosen because they have high TB rates but different patterns of disease. South Africa has a high HIV and TB co-infection rate, while Indonesia faces challenges like smoking and undernutrition. Studying these diverse settings will help researchers understand TB transmission better and develop strategies that work in different environments.

When is the study starting and how long is it expected to run for?
The study will commence in February 2026 and will run for 3 years, to December 2028.

Who is funding the study?
Wellcome Trust (UK)
Gates Foundation (USA)

Who is the main contact person?
Prof Limakatso Lebina, Limakatso.lebina@ahri.org
Prof Bachti Alisjahbana, balisjahbana@gmail.com
Prof Emily Wong, Emily.Wong@ahri.org

Contact information

Study information

Eligibility

Locations

Countries of recruitment

• Indonesia
• South Africa

Study participating centres

Results and Publications

Study outputs

Additional files

48655 ATTIS Protocol V1.2_05 Dec 2025.pdf

Protocol file

Editorial Notes

17/12/2025: Trial's existence confirmed by Wellcome.