Quick answer. Tuberculosis is a bacterial infection (usually of the lungs) spread through the air; it is curable with several months of antibiotics, and in Singapore active TB is a notifiable disease managed through the National Tuberculosis Programme with subsidised, often free, treatment under directly observed therapy.
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Tuberculosis (TB) is an infection caused by the bacterium Mycobacterium tuberculosis. It most often affects the lungs (pulmonary TB) but can involve other parts of the body such as the lymph nodes, spine, kidneys or brain. TB spreads through the air when a person with active lung TB coughs, sneezes or speaks.
TB is curable. With the correct combination of antibiotics taken for the full prescribed course, the great majority of people make a full recovery. In Singapore, active TB is a legally notifiable disease, and care is coordinated through the National Tuberculosis Programme and the Tuberculosis Control Unit (TBCU) at Tan Tock Seng Hospital.
At a glance
| Feature | Latent TB infection | Active TB disease |
|---|---|---|
| Symptoms | None; the person feels well | Cough, fever, weight loss, night sweats |
| Infectious to others | No, cannot spread TB | Yes, lung/throat TB can spread through the air |
| Chest X-ray / sputum tests | Usually normal, sputum negative | Often abnormal X-ray, sputum may be positive |
| Treatment | Preventive therapy to stop progression | Multi-drug antibiotics for several months |
How TB spreads
TB bacteria are carried in tiny airborne droplets released when someone with active TB of the lungs or throat coughs, sneezes, sings or speaks. Another person can become infected by breathing in these droplets, usually after prolonged close contact such as sharing a home or enclosed space.
TB is not spread by shaking hands, sharing food or drink, touching surfaces, or kissing. Most people who breathe in the bacteria do not become sick; their immune system contains the infection, which is then called latent TB.
Latent TB vs active TB
In latent TB infection, the bacteria are present but kept inactive by the immune system. The person has no symptoms, feels well and cannot pass TB to others. However, the latent infection can later ‘wake up’ and become active, especially if the immune system weakens (for example with HIV, diabetes, certain medications or older age).
In active TB disease, the bacteria multiply and cause illness. Lung TB produces symptoms and can be contagious. Treating latent TB with preventive therapy reduces the risk of it progressing to active disease.
Symptoms to watch for
- A persistent cough lasting three weeks or more
- Coughing up phlegm, sometimes streaked with blood
- Unexplained weight loss and loss of appetite
- Fever, especially low-grade fever in the evenings
- Drenching night sweats
- Tiredness and feeling generally unwell
- Chest pain or breathlessness
See a doctor if a cough lasts more than three weeks, particularly with fever, weight loss or blood in the phlegm. Coughing up significant amounts of blood is a reason to seek urgent medical care.
How TB is diagnosed
Diagnosis usually combines several tests. A chest X-ray looks for changes in the lungs. Sputum tests (smear microscopy, culture and molecular tests such as GeneXpert) check phlegm for TB bacteria and can detect drug resistance. For suspected latent TB, a tuberculin skin test (Mantoux) or a blood test (interferon-gamma release assay, IGRA) is used.
Because lung TB can spread, prompt diagnosis allows treatment to start quickly and reduces the chance of infecting others.
Treatment, DOTS and the National TB Programme
Active TB is treated with a combination of antibiotics taken for at least six months. A standard course typically begins with four drugs (such as isoniazid, rifampicin, pyrazinamide and ethambutol), followed by a continuation phase with fewer drugs. Completing the full course is essential to cure the infection and prevent drug-resistant TB.
In Singapore, treatment is delivered through Directly Observed Therapy (DOT/DOTS), where a healthcare worker watches the patient take each dose to ensure the medication is taken correctly and consistently. TB treatment is heavily subsidised, and medication for patients treated under DOT at the TBCU is provided free of charge. Drug-resistant TB is referred to the TBCU at Tan Tock Seng Hospital.
Notification, contact tracing and prevention
Under the Infectious Diseases Act, doctors must notify active TB to the authorities. The TBCU then carries out contact tracing, screening close contacts so that anyone infected can be tested and treated early. This protects families and the wider community.
If you are diagnosed with infectious TB, follow your treatment plan closely, cover your mouth when coughing, ensure good ventilation, and attend all DOT and follow-up appointments. Once treatment has started and a person responds, they usually become non-infectious relatively quickly, but the full course must still be completed.
What to expect during treatment
Starting TB treatment can feel daunting, but knowing what lies ahead helps. You will usually take a combination of tablets and attend regular appointments. In Singapore, treatment is supported by Directly Observed Therapy (DOT), where a healthcare worker observes each dose to help you stay on track and complete the full course. Many people start to feel better within a few weeks, but it is essential to keep taking the medicines for the entire prescribed period, even once symptoms improve, to fully clear the infection and prevent drug resistance.
Some TB medicines can cause side effects, such as a temporary orange-red colour to urine and tears (from rifampicin, which is harmless), nausea, or, less commonly, liver irritation or numbness and tingling. Report yellowing of the eyes, persistent vomiting, severe rash, vision changes or new numbness to your team promptly, as the regimen may need adjusting. Tell your doctor about other medicines and contraception, since rifampicin can reduce the effectiveness of hormonal contraceptives.
Supporting recovery and protecting others
Rest, good nutrition and avoiding alcohol support recovery and reduce the strain on your liver. While you are still infectious, cover your mouth when coughing, ensure rooms are well ventilated, and follow any advice about limiting close contact. Once you respond to treatment, you usually become non-infectious relatively quickly, but you must still finish the full course. Attend all follow-up and contact-tracing appointments so that household members and close contacts can be screened and treated if needed.
Common questions
Will I have to stay in hospital?
Many people are treated as outpatients. Hospital admission may be needed if you are very unwell, highly infectious, or have complications, but most treatment is taken at home with DOT support.
Is TB treatment really free in Singapore?
TB treatment is heavily subsidised, and medication for patients treated under DOT at the Tuberculosis Control Unit is provided free of charge. Ask your care team about financial assistance for those completing treatment.
Can I go back to work?
Once you are no longer infectious and feeling better, your doctor can advise on returning to work or study. The timing depends on your type of TB and how you respond to treatment.
Related guides
- Best Respiratory & Lung Clinics in Singapore — our editorial shortlist
- Bronchiectasis
- Pulmonary Embolism
- Pleural Effusion
Sources
- Communicable Diseases Agency (CDA) – Tuberculosis
- CDA – National Tuberculosis Programme
- MOH – Financial assistance for TB patients completing DOT
- HealthHub – Tuberculosis
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