New study reveals the silent tuberculosis epidemic in South Africa

A groundbreaking study led by the University of Cape Town (UCT) has unveiled a concerning trend among adults living with tuberculosis (TB) patients: the majority of TB cases is asymptomatic at the time of screening. Published in The Lancet Global Health, the research highlights the pressing need to rethink how TB testing is approached in South Africa and other high-burden countries.

Dr Simon Mendelsohn, the lead author of the study and a senior researcher at UCT’s South African Tuberculosis Vaccine Initiative (SATVI), emphasised that the standard practice of testing individuals only after they exhibit symptoms, such as a persistent cough, is grossly inadequate. “National surveys typically determine who gets a sputum test by first checking for symptoms or conducting a chest X-ray. This new study shows that these methods miss a significant number of TB cases, particularly those individuals who are not yet symptomatic,” explained Mendelsohn.

The researchers, part of the RePORT South Africa Network, visited households in three communities and offered sputum laboratory tests to all adult contacts of TB patients, regardless of their symptom status or chest X-ray results. The findings were alarming: roughly 80% of those diagnosed with TB showed no symptoms, and more than half of these had chest X-rays that appeared normal yet were still capable of transmitting the disease. “Relying solely on symptoms or X-rays means many infectious individuals escape detection and treatment in the early stages of the disease,” Mendelsohn warned.

This study's implications for public health are profound. As TB continues to be a leading cause of mortality in South Africa, the research advocates for a seismic shift in current TB screening protocols. “IIf we want to cut transmission, we need to find TB earlier — by going into communities and offering tests before individuals recognise their symptoms,” stated Mendelsohn.

In light of the findings, the researchers propose a series of proactive measures:

• Take testing to people: Implement community-level screening for household contacts of TB patients and other high-risk groups, regardless of their health status.
• Update screening protocols: Integrate microbiological tests into programmes that currently rely solely on symptoms and chest X-rays to reduce the number of missed TB cases.
• Measure the real burden: Adjust national TB surveys to include universal sputum testing for contacts and other at-risk groups to ensure silent TB cases are identified and accounted for.

The full study, titled “Screening for asymptomatic tuberculosis among adults with household exposure to a patient with pulmonary tuberculosis: a prospective observational cohort study,” can be accessed through medical journals and digital platforms.