Explainer: When community transmission can be considered ‘widespread’

SINGAPORE — The coronavirus transmission in Singapore has not yet reached a level where it can be described as “widespread”, because the authorities are still able to isolate and contain the spike in new cases, Associate Professor Kenneth Mak said.

The director of medical services at the Ministry of Health (MOH) added that while there has been some community transmission here, it is still “potentially controllable” and the authorities intend to ramp up its containment strategies to curb the spread of the disease.

Assoc Prof Mak was responding to questions from the media during a briefing on Friday (April 3) by the multi-ministry task force that is spearheading Singapore’s response to the coronavirus.

He said: “It is not our assessment at this stage that we have widespread transmission to the extent that our ring fencing and containment strategies have failed.

“We will continue to endeavour and continue to persevere because we believe this will make a difference in allowing the safe-distancing measures to take root and allow (the locally transmitted cases) to settle down.”

TODAY examines under what circumstances the coronavirus transmission could be considered as “widespread”.

FACTORS THAT INDICATE A WIDESPREAD COMMUNITY TRANSMISSION

Speaking to TODAY, infectious disease experts said that there is no hard and fast rule in determining what constitutes a “widespread” community transmission.

However, they said that there are some factors that can indicate whether the infection can no longer be contained.

These include whether there is still capacity in Singapore’s healthcare system to take in infected patients and whether it is still possible to conduct contact tracing to establish links between cases.

Dr Leong Hoe Nam, an infectious diseases specialist at Mount Elizabeth Novena Hospital, said he would consider the disease widespread when Singapore cannot cope with the numbers for contact tracing.

Dr Paul Tambyah, the president of the Asia Pacific Society of Clinical Microbiology and Infection, said that another indicator is the number of active clusters there are in the community.

“With more and more clusters that are still open, the line (between whether community transmission has become widespread or not) becomes greyer and greyer,” he said.

Another sign that the disease has become widespread is when the hospitals are unable to take in infected patients or treat patients who require intensive care, Dr Leong said.

HOW FAR IS SINGAPORE FROM A WIDESPREAD COMMUNITY TRANSMISSION?

The experts told TODAY that Singapore is close to reaching the point of a widespread community transmission.

Associate Professor Hsu Li Yang, who heads the infectious diseases programme at the National University of Singapore’s Saw Swee Hock School of Public Health, said that this can be seen from the number of cases with no known links and new clusters that have emerged in the last two weeks.

He added that by next week, it would be clear whether the stricter travel restrictions and safe-distancing measures that have been put in place have been successful and whether Singapore should expect more local transmissions to take place.

On that note, Dr Leong stressed that it is now more important than ever that individuals maintain safe distancing.

Agreeing, Dr Tambyah said: “This is a particularly critical time as we now have vulnerable populations such as residents of senior citizen homes and migrant workers living in crowded dormitories who are part of new clusters.

“It will be very important to ensure that the most vulnerable are protected.”