Could Symptom-Free People Be Unknowingly Passing TB to Others? Major Study Launches in South Africa and Indonesia
23 October 2025
KwaZulu-Natal, South Africa & West Java, Indonesia, 23-10-2025 – A groundbreaking new international study will investigate whether people with tuberculosis (TB) who show no symptoms are unknowingly spreading the disease – potentially changing the way the world tackles TB.
South Africa and Indonesia represent two of the World Health Organisation regions with the highest TB burdens. In South Africa, TB remains one of the leading causes of death.
Asymptomatic TB is one of the most complex issues hindering progress in the fight against TB. Evidence suggests that half of all people who have active TB are unaware of their status – because they have no symptoms. In this condition, the bacteria that causes TB is present in the lungs and sputum but does not trigger signs of illness – such as coughing, fever, extreme tiredness and appetite loss. Affected people might not realise they are sick or be diagnosed until their lungs are damaged by the bacteria. It is not yet clearly understood how best to find people with asymptomatic TB and whether this group of people can spread TB to others. The ‘Asymptomatic TB Transmission in Indonesia and South Africa (ATTIS)’ study seeks to address this critical gap in our understanding of TB transmission.
Researchers from Africa Health Research Institute and Padjadjaran University will recruit 90,000 adult volunteers from households with children to take part in community-based TB screening, including chest X-rays, in KwaZulu-Natal, South Africa, and West Java, Indonesia. Among volunteering households, children will be tested for immune responses to Mycobacterium tuberculosis complex (MTBC), the bacteria that causes TB, enabling the study team to assess whether asymptomatic TB in adults is contributing to transmission within families.
ATTIS is co-led by Professor Limakatso Lebina (Africa Health Research Institute (AHRI) director for clinical trials), Professor Emily Wong (AHRI and University of Alabama Birmingham faculty member), and Professor Bachti Alisjahbana (chair of the Research Centre for Care and Control of Infectious Diseases (RC3ID) at the University of Padjadjaran). It is jointly funded by Wellcome and the Gates Foundation for $19.5-million (R340-million) over three years.
“TB is often thought of as a disease that makes people very sick, with symptoms such as persistent cough and weight loss,” said Professor Lebina. “But we know about half of people with TB don’t feel ill at all. If we can understand if they are still passing the infection on, and at what rates, that will be a game-changer for TB control globally.”
The project will also integrate innovative diagnostics and biological investigations. These include testing of exhaled breath and biobanking of blood samples to support cutting-edge research to help us better understand asymptomatic TB, and to detect the condition earlier.
“Currently TB is detected when people seek care at clinics and hospitals when they feel sick,” said Professor Wong. “If the ATTIS study shows that people who feel well have infectious asymptomatic TB, then we might have to flip the paradigm of global TB control away from clinics and screen people in their communities.”
“This collaboration between Indonesia and South Africa brings together two of the countries whose populations are most affected by TB, each with world-class research capacity,” said Professor Alisjahbana. “By working across continents, we can generate stronger evidence, compare findings across different settings, and build a shared foundation for global TB control.”
Source: Africa Health Research Institute
