Following the confirmed cases of four individuals with tuberculosis (TB) in the same HDB block, the Ministry of Health (MOH) will offer voluntary screening free-of-charge for residents and former residents.

On Oct. 24, MOH stated in a news release that the precautionary measure would be taken after detecting the cases at Blk 174D, Hougang Avenue 1.

Identified and investigated

MOH was notified of the cases on Oct. 10, who were diagnosed between Jan. 2018 to June 2020.

The Singapore TB Elimination Programme conducted an investigation, which revealed that the four cases lived in different units, did not identify each other as close contacts, and did not interact other than living in the same block.

MOH said:

"The cluster was subsequently determined due to the results of the genetic sequencing performed in October 2020 as part of retrospective testing of TB cases to determine possible linkages. This revealed that all four cases have similar genetic make-up."

It added that TB clusters are usually found among people in close contact, and that this particular cluster does not fit the typical TB spread.

Of the four cases, two have completed treatment while the other two are undergoing treatment. TB cases rapidly become non-infectious once treatment starts, so the cases are not considered a public health risk.

TB is typically spread through close and prolonged contact with infectious cases

MOH added that TB is typically spread through close and prolonged contact with an infectious individual, and not by contact with items or surfaces touched by a person with TB.

The risk of transmission to people who are not close contacts of a TB case is very low, so screening is not necessary for individuals who may have occasionally visited the block.

TB may be uncommon these days, but it used to be more widespread in Singapore.

Latent TB infection is not uncommon in the population, as TB had been prevalent in Singapore until the 1970s. Older Singaporeans could have been exposed to TB and acquired latent TB infection when they were younger. People with latent TB do not experience symptoms of TB and are not infectious.

Thankfully, TB is curable as long as the cases adhere to treatment, which allows us to prevent outbreaks.

Strongly encouraged to go for screening

Screening will be conducted free of charge at the Tuberculosis Control Unit (TBCU) located at Moulmein Road, from Oct. 26 onwards.

Officers from the unit and the National Centre for Infectious Diseases (NCID) will conduct house visits to all units at the affected block.

Residents may make appointments for the screening with them, or call the TBCU hotline at 6248 4430. Residents who have stayed at the block from Feb. 2020 and wish to go for the screening can also make an appointment by calling the hotline.

The screening is voluntary but the MOH strongly encourages residents to be screened.

Those with positive screening results will be offered appropriate advice and follow-up. Those with active TB will be treated immediately while those with latent non-infectious TB will be monitored and treated if necessary.

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