SINGAPORE - All residents of a Housing Board block in Yishun have been asked to go for swab tests starting from Tuesday (June 1) after cases of Covid-19 infections have been detected there.
In a letter to residents seen by The Straits Times on Monday, Grassroots Adviser to Nee Soon GRC Faishal Ibrahim said this was a precautionary measure to ensure the safety and well-being of residents of Block 745 Yishun Street 72.
He added that residents living in surrounding blocks need not be tested unless they have visited households in Block 745 between May 15 and May 24.
"Nee Soon Town Council has done a thorough cleaning and disinfection of the common area at Block 745 and the surrounding blocks," he said.
On May 24, the 304 residents of Block 559 Pasir Ris Street 51 were asked to go for testing after four Covid-19 cases were detected in two households there.
The Ministry of Health said on May 25 that all the tests had come back negative.
Earlier, MOH had identified 11 Covid-19 cases from at least four households in Block 506 Hougang Avenue 8. Two of these were detected from a mandatory testing exercise for residents.
A total of 405 residents and visitors of the block were tested on May 21 and May 22.
Responding to a question raised at Monday's multi-ministry task force press conference, on the circumstances requiring all residents from a block to be tested, Singapore's Director of Medical Services Kenneth Mak said that when clusters in the domestic setting are picked up, the team will start by looking at the obvious chains of transmission and "the modes of transmission that are of concern".
"When we pick up several cases that occur within a fixed geographic vicinity, then we have to be concerned that there may also be chains of transmission that occur to other people that live in that same area," said Associate Professor Mak. "And this is the reason why we would then extend and carry out testing operations."
These testing operations are also reinforced by looking at data from other testing modalities, such as wastewater testing.
Screening wastewater samples could complement clinical testing and provide an additional indicator to assess the level of Covid-19 spread within a community. This is because infected individuals, including those who have mild symptoms or are asymptomatic could still be shedding the virus in their stool.
Assoc Prof Mak noted that this may raise concerns as it could suggest that there are additional people who may be asymptomatic but are potentially infectious to others, creating a sense of urgency to launch testing operations at the respective housing blocks.
"So we look at each cluster on a case-by-case basis, looking at the circumstances and making that decision (on) whether we want to organise these testing operations," he said.
Though such operations are not easy to carry out, Assoc Prof Mak noted that they are necessary as part of Singapore's aggressive testing to stay ahead of the curve and prevent further infections in the community.