For the past four days, Singapore has reported more than 1,000 new Covid-19 cases daily, bringing the total number to 11,178 as of April 23, 12pm.

On April 21, Prime Minister Lee Hsien Loong addressed the nation for the fifth time and announced that the circuit breaker period will extend for another four weeks till June 1, 2020.

While the cases linked to foreign worker dormitories contribute to the daily large spikes, the number of cases arising from the rest of the community remains a concern.

Covid-19 situation in Singapore after three weeks of circuit breaker period

Here are some graphs to take stock of the progress Singapore has made over the past three weeks of the circuit breaker period.

The circuit breaker period officially commenced on April 7 and a downward trend can be observed for Covid-19 cases with links identified in the community, which suggests the measures are effective to some extent.

In contrast, there is no clear downward trend for the daily unlinked cases in the past three weeks, hovering at around 19 cases reported each day.

This was also what PM Lee highlighted in his speech to explain the need to tighten measures and extend the circuit breaker.

Furthermore, there are also other work pass permit holders residing outside of dormitories with the possibility of interacting with the rest of the community.

There is, however, an upward trend of Covid-19 cases (both linked and unlinked) in the past three weeks among these workers who do not live in the dormitories.

As a precautionary move, the Ministry of Manpower (MOM) has required all work permit holders and S Pass holders in the construction industry to be placed on mandatory stay-home notices (SHNs) from April 20 to May 4 (both dates inclusive), according to a news release from April 18.

Overall, the daily number of Covid-19 cases in Singapore, excluding cases from foreign worker dormitories, did not seem to decrease significantly in the past three weeks.

PM Lee in his speech also mentioned that "there is a larger, hidden reservoir of Covid-19 cases in the community, and this reservoir is the source of these unlinked cases, which we have not detected”.

How big is this hidden reservoir of Covid-19 cases?

In response to Mothership's query, infectious disease specialist at Mount Elizabeth Novena Hospital, Leong Hoe Nam estimated that there are at least five such unknown infected individuals in the community at one time.

"I think there are at least five such individuals at any one time... But more likely 10-15. They are spreading viruses unknowingly."

Leong said that anyone can be asymptomatic and he is concerned of the number of unlinked cases.

"I am concerned of this small unlinked. You can have a super spreading event and all we have done is busted."

This is also why Leong is supportive of tightening the social interaction measures and said that the initial circuit breaker measures were "grossly insufficient".

Supportive of tighter measures

He added that he would prefer even tighter measures such as disallowing jogging outside without masks.

"The tighter the controls, the more miserable we are, the more the virus dies."

Leong mentioned that he is supportive of what fellow doctor, Billy Tan, wrote on Facebook last week.

On Tan's post, he pointed out allowing people to exercise outside without masks was a "loophole" and that could facilitate the spread of the virus.

"The tighter we lock down the more successful we are and the earlier we get out of it. I hate it. But the earlier and quicker we swallow the bitter pill, the sooner we move on," Leong said.

Measures can be loosened if daily cases reduced to less than 5

Looking ahead, Leong said that we can consider loosening the circuit breaker period if the daily number of cases in the community is reduced to less than five.

With the tighter restrictions, he believes Singapore should be able to achieve that goal by June.

Having said that, there is definitely no room for complacency as he said Singapore should still aim for zero cases.

Top photo via Masagos Zulkifli's Facebook