SINGAPORE – The Ministry of Health (MOH) will be conducting a mass mandatory tuberculosis (TB) screening exercise from Jan 11 to 15 for residents and workers of blocks 1 and 3 Jalan Bukit Merah, ABC Brickworks Market and Food Centre and Thong Kheng Seniors Activity Centre @ Queenstown.

Ten new tuberculosis cases in the country have been discovered to be part of a Jalan Bukit Merah cluster that first surfaced in 2022. In total, the cluster now has 28 cases.

Voluntary screening will also be offered to other groups, including frequent visitors to blocks 1, 2 and 3 Jalan Bukit Merah and the market and food centre. Around 3,000 individuals are expected to participate in the exercise, which is being held to identify any undetected active cases and prevent further transmission.

The Straits Times answers some questions about the disease.

Q: Does this screening exercise mean that TB has resurfaced in Singapore?

A: TB is endemic in Singapore. While active TB cases have been going down, there are new cases every year. There were around 1,200 new active TB cases in Singapore in 2022.

Latent TB infection is not uncommon here. Its prevalence increases with age, ranging from 2 per cent among those aged between 18 and 29 years old, to 29 per cent among those aged between 70 and 79 years old.

Q: What is the difference between latent TB infection and active TB disease?

A: A person with active TB disease is likely infectious and may have symptoms such as a prolonged cough, persistent fever, night sweats, weight loss, fatigue, chest pain and, on rare occasions, blood in sputum. Such patients need to be treated promptly. If not, they can become sicker and more infectious, an MOH spokesman said. The disease can also become more difficult to treat if a person waits too long and the TB bacteria start to invade more parts of the body, he said.

A person with latent TB infection does not have symptoms and cannot spread it to others, as the TB bacteria remain inactive in the body. However, the disease can be activated months or even years later due to a weakened immune system, certain medical conditions or other factors.

Q: How will the onsite screening be conducted?

A: From Jan 11 to 13, staff from MOH and the National Centre for Infectious Diseases (NCID) will be going from door to door to conduct mandatory screening in the homes of residents of blocks 1 and 3 Jalan Bukit Merah. Stations for mandatory screening will be set up at the open-air carpark next to Block 2 from Jan 11 to 15, to cater to those working at the blocks or the ABC Brickworks Market and Food Centre.

The screening for those who are offered voluntary screening will also be done at the stations at the car park, on Jan 14 and 15, but MOH said it is strictly by appointment only. To make an appointment, go to https://go.gov.sg/tbs

Q: What is the screening process for TB at Jalan Bukit Merah?

A: The screening will be done in two stages. The first stage, from Jan 11 to 15, involves administering a blood test to check for TB exposure or latent TB infection.

In the second stage, from Jan 18 to 29, those who tested positive on the blood test will have to undergo additional evaluation, including a chest X-ray and clinic review. This is done to see if they have active TB disease.

Q: Do I have to pay for the screening?

A: No, both mandatory and voluntary screenings are free of charge, with priority given to those for whom screening is mandatory, MOH said.

Q: How is TB treated?

A: Those with latent TB infection have to take a drug for four to six months.

Those with active TB disease have to take a combination of drugs for six to nine months. They become non-infectious and their symptoms will resolve very quickly.

But if they do not finish their six- to nine-month course, the rate of relapse is very high. More than getting TB again, they may get resistant forms of TB, said the MOH spokesman.

To ensure that they take the drugs across the entire period, they will have to make a trip to the polyclinic to take their medication, under the observation of a healthcare worker.

Typically, in the first two months, they need to take their medications daily. In most cases, after the first two months, they can take it three times a week, but they will still have to do that at the polyclinic, said an NCID spokesperson.

Q: If I have latent TB infection, what are the chances of it developing into active TB disease?

A: About 10 per cent of those with latent TB infection will develop active TB disease over their entire lifetime, but the risk is highest in the first two years after being infected, said the NCID spokesperson.

Half of this group will develop it in the first two years after exposure, while the rest will develop it later during their lifetime. 

The treatment for those with latent TB infection is about 60 per cent to 90 per cent effective in preventing a person from having active TB disease.

Q: I have recovered after being treated for active TB disease. Can I get it again?

A: The likelihood of being infected again is there, but it is extremely low. More than 95 per cent of those who complete their treatment for active TB disease are successfully treated. There is a 5 per cent chance of relapse, but this can occur many years down the road, NCID said.

There is a TB vaccine given at birth, known as Bacillus Calmette-Guerin or BCG, which is effective in preventing serious forms of TB, such as TB targeting the linings of the brain in young children, but it does not protect against lung TB in adults.

Q: Can I get TB from shaking hands with a person who has TB disease?

A: No. TB is not spread through shaking hands, kissing, touching bed linen or toilet seats.

Q: Does mask-wearing help protect me from getting TB?

A: In general, individuals who are inclined to wear masks for protection against Covid-19 or other respiratory diseases, can do so. There is no specific recommendation for the Jalan Bukit Merah area because the risk there at this point is no different from anywhere else, said MOH.

The key objective is for people to come forward to be screened.

So far, most of the people identified through TB screening had latent TB infections.

Although they were not infectious, they were given treatment to prevent them from getting TB down the road.

Q: What precautions can I take if I am showing symptoms of active TB disease?

A: Individuals with TB symptoms should wear a mask and avoid going to crowded places.

When an individual is diagnosed with active TB, he will be started on treatment immediately and placed on medical leave.

Once treatment starts, he will quickly become non-infectious. There is no need to close workplaces or places where a recently diagnosed active TB case has visited.