Science Talk: Is tuberculosis still a problem in Singapore?

Ahead of World Tuberculosis Day on March 24, NCID associate consultant Tay Jun Yang answers some common questions about the disease.

Over the past 16 years, the tuberculosis incidence rate in Singapore has remained between 30 and 40 per 100,000 people. PHOTO: ST FILE

SINGAPORE - Every year, World Tuberculosis Day falls on March 24.

The day is commemorated to raise public awareness about the health, social and economic consequences of tuberculosis (TB), and to step up efforts to end the global TB epidemic.

The World Health Organisation estimates that 9.9 million people worldwide developed the disease in 2020, with 1.5 million deaths globally.

Over the past 16 years, the TB incidence rate in Singapore has remained between 30 and 40 per 100,000 people.

Given that TB was prevalent in Singapore before the 1960s - an immunisation programme for newborn babies was started in the mid-1950s - there is still a sizeable number of older people in Singapore with latent TB infection.

This means that while the bacterium is present in their bodies, they do not show any symptoms and are not infectious as the bacterium is suppressed by the immune system.

These patients can potentially develop active TB disease - when symptoms start to show and the patient becomes infectious - when their immunity wanes, posing a risk of transmission in the community.

Q: How does TB spread, and are family members in the same household at higher risk of contracting TB?

A: TB is a disease that primarily affects the lungs. It spreads through close and prolonged contact with a person who has infectious TB.

TB affecting the lungs (pulmonary) or voice box (larynx) is infectious and it can spread when the infected person coughs, sneezes or speaks.

Hence, people living in the same household, or those who are in frequent, close contact with the affected person, are at higher risk of being exposed to TB and getting infected.

Children below the age of five and people with weakened immune systems are also at increased risk of developing TB.

Q: What precautions should I take to minimise the risk to family members?

People diagnosed with infectious TB should immediately start treatment, which usually involves a combination of several antibiotics, and be put on medical leave for the first two weeks.

While they will become non-infectious after two weeks of treatment, they will still need to complete a minimum six-month course of treatment. During this time, those on treatment do not pose a risk to their family members or other people.

However, during the first two weeks of treatment, they should stay at home except when attending directly observed therapy treatment at the Tuberculosis Control Unit in Moulmein Road or a polyclinic. This treatment requires patients to take their medications under the observation of a healthcare worker.

They should also wear a mask in the presence of other people during the first two weeks of treatment and practise good cough etiquette, such as covering their mouth with a tissue when they cough or sneeze if unmasked.

Q: Where do I go if I want to be screened for TB? What is the TB screening process?

A: People who have been exposed to a person with infectious TB may be called by the NCID to undergo contact screening at the Tuberculosis Control Unit. During screening, they will undergo blood tests and possibly a chest X-ray to determine if they have been exposed to TB.

If diagnosed with active TB disease, they will promptly be started on the appropriate treatment.

If there is evidence of exposure to the TB bacteria but no active disease is detected, also termed latent TB infection, patients will be given a course of preventive therapy to prevent them from developing active TB disease in future.

People who have been exposed to a person with infectious TB may be called by the NCID to undergo contact screening at the Tuberculosis Control Unit (pictured). PHOTO: ST FILE

Q: What symptoms should I look out for?

A: Symptoms of TB include prolonged cough, which is defined as coughing for three weeks or more; coughing blood; weight loss; night sweats or persistent fever.

Individuals who are unwell and display these symptoms should seek medical attention early to ensure prompt diagnosis and treatment.

Q: Can TB be cured?

A: TB is curable. Following TB screening, an outcome from the TB test will determine the course of treatment.

If the test is positive, the doctor will then determine if the person has active TB disease or latent TB infection.

A person with active TB in the lungs or voice box may be infectious and may exhibit specific TB symptoms. If diagnosed with active TB disease, the person should be treated immediately and will need to take at least six months of medications under the direct supervision of a healthcare professional.

TB is curable and more than 95 per cent of people with drug-sensitive TB, which means that the TB bacteria are not resistant to any of the drugs targeted to kill them, are cured as long as they adhere to the prescribed treatment. Otherwise, TB may recur or become resistant to first-line anti-TB drugs.

A person with latent TB infection does not develop symptoms and does not spread TB to others, but the TB bacteria remain in the body.

If diagnosed with latent TB infection, one can be started on a course of preventive treatment to prevent the development of active TB disease in future.

Q: How is TB treatment carried out? Do I really need to go to the clinic and be observed taking my medication every day?

A: The full course of treatment for drug-sensitive TB typically requires patients to take several medications for six to nine months.

Adherence to treatment and medical appointments is important to ensure proper recovery and to prevent the spread of TB in the community.

Poor adherence to medication can lead to drug-resistant forms of TB, which take longer and are harder to treat.

Directly observed therapy is currently the best way of ensuring patients' response and adherence to treatment for their personal health and others around them. An outreach programme is available for patients who are unable to visit the clinics for their treatment due to age or infirmity.

Q: Why am I not protected even though I was given the BCG vaccination as a baby?

A: The Bacillus Calmette-Guerin (BCG) vaccine is administered to all children at birth and protects babies and young children against other serious forms of TB, such as TB meningitis, which affects the brain lining, and disseminated TB, where the bacteria have spread to multiple organs within the individual.

However, it offers limited protection against pulmonary TB, which refers to TB in the lungs. This is the most common form of TB disease among adults.

Hence, people may not be protected from developing pulmonary TB even though they have undergone the BCG vaccination.

Q: How affordable is TB treatment, and are there any subsidies provided?

A: TB treatment is heavily subsidised for Singaporeans and permanent residents. Additional charges would apply for non-basic tests.

Q: How should someone with TB take better care? Are there any specific areas the person should look out for?

A: People diagnosed with TB should adhere strictly to the medication regime.

They should ensure that they take all their medications for the full prescribed period on a regular basis, and make sure they do not skip doses or stop taking the medications early, even if the symptoms go away and they start to feel better.

This ensures that the TB bacteria are successfully eliminated. A healthcare professional will advise them on the side effects to look out for and what they should do if they develop side effects after taking the medication.

If you are caring for someone with TB, give your full support and encourage the person to take the medications.

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