Despite being preventable and curable, tuberculosis (TB) continues to loom large over the global public health landscape. As the second-leading infectious killer following COVID-19, TB claimed over 1.3 million lives worldwide in 2022, with an estimated 10.6 million active cases. 

TB has been endemic in Singapore. In recent years, the city-state has seen a steady decline in TB rates, falling for the fourth straight year in 2022, which reported 1,251 new active cases. Nevertheless, a recent cluster in a local community highlights how complex and challenging it is to keep a rein on the disease.

“Controlling TB transmission is challenging as individuals may develop active TB months or even years after initial exposure,” says Adj A/Prof Adrian Kee, Head & Senior Consultant in the Division of Respiratory & Critical Care Medicine, Department of Medicine, NUH. “With the advent of state-of-the-art genetic sequencing technologies, we can more accurately trace TB cases and conduct screening—but awareness remains key in the fight against the disease.”

Tackling TB effectively hinges on building awareness and understanding. Below, key questions are addressed to shed light on various aspects of TB and its management.

TB is primarily an airborne disease. It’s caused by a bacterium called Mycobacterium tuberculosis, which usually targets the lungs, though other organs, such as the kidneys and the brain, are susceptible too.

Transmission occurs when an individual with active lung TB coughs or sneezes, releasing bacteria-laden droplets into the air, which can then be inhaled by others, leading to infection. Unlike casual interactions that last only minutes or hours, close and prolonged contact over days to weeks is typically necessary for transmission. Activities like sharing utensils, shaking hands or touching toilet seats do not pose a risk of spreading TB.

Symptoms of active TB include a persistent cough (lasting more than three weeks), fever, night sweats, weight loss and fatigue. Occasionally, patients might notice blood in their sputum. Early detection of these symptoms is crucial for effective treatment.

Meanwhile, those with latent TB infection are asymptomatic and non-contagious. However, about 10% of these individuals may develop active TB over their lifetime—with the highest risk occurring within the first two years of infection.

TB detection involves a combination of clinical assessment, chest X-rays and microbiological tests like sputum analysis. Recent advancements in genetic sequencing have given healthcare professionals a shot in the arm regarding their capabilities to accurately link TB cases and pinpoint outbreaks.

Treating active TB typically involves a multi-drug regimen lasting at least six to nine months. Patients generally become non-infectious within two weeks of starting treatment. “Strict adherence to the treatment plan is of paramount importance to prevent a relapse and the emergence of multi-drug-resistant TB strains, which can escalate fatality rates to as high as 58%,” emphasises Adj A/Prof Adrian.

Preventive treatment for individuals with latent TB infection, aimed at reducing the likelihood of developing active TB, involves taking one type of medication for four to six months.

Preventing TB requires minimising exposure to active cases and addressing latent infections, especially among high-risk populations. Participating in evidence-based public health initiatives, such as targeted screening and BCG vaccination for newborns, is crucial in nipping TB in the bud.