On April 3, an assistant manager at the Lido branch of McDonald's saw a doctor for a sore throat and fever. She was given five days' medical leave.

At the end of her medical leave on April 8, the 44-year-old mother of a teenage boy went back to the doctor.

This time, she was sent to Sengkang General Hospital for a Covid-19 swab test.

It was positive.

Over the next nine days, six other employees of the fast-food chain, who had worked across nine outlets, were diagnosed with the coronavirus.

They were a mix of restaurant managers and crew. The youngest was a 25-year-old man and the oldest a 74-year-old woman. Two of them lived together, sharing a room.

Over at the Ministry of Health, doctors and officials watched with increasing concern.

Steps had already been taken by McDonald's to contain this cluster, but did they go far enough?

The company had told all employees from the affected outlets to isolate themselves for 14 days. These restaurants were also closed and underwent deep cleaning.

On April 18, McDonald's stopped takeaways - Singapore had already banned dining-in - and switched to delivery and drive-through service only.

But the ministry - by then battling huge numbers of foreign workers who got infected at worksites and living quarters - felt more had to be done.

A decision was made: From 11am the following day - April 19 - all 135 McDonald's outlets would close down till May 4.

The decision wasn't taken lightly.

The chain employs more than 10,000 people and serves more than six million hungry customers every month.

But, as McDonald's noted on its website: "These are unprecedented times for all of us. With the safety of all our customers and employees as the top priority, we will do all we can to help Singapore flatten the curve."

The company promised to pay salaries to its employees while operations were suspended.

FOUR WAVES

On Jan 23, Singapore saw its first case of Covid-19, a 66-year-old Chinese man from Wuhan, surnamed Wang, in town with his family for a 10-day holiday.

In the 100 days since, the number of infections exploded to 17,548 as of noon yesterday, with more than 15,000 of them foreign workers. Seventeen patients have since died.

Four waves of infection can be discerned so far.

The first was from Jan 23 to Feb 1, when there were 18 cases involving Chinese tourists from Wuhan as well as Singapore residents returning from the city on special evacuation flights.

The second was from Feb 3 to March 10. Infections rose by 152 cases when Singaporeans and residents with links to infected Chinese visitors came down with the virus. New cases with no apparent links to travellers from Wuhan also started to appear.

A third wave started from around March 11 to April 1, when 858 people were diagnosed with Covid-19. The majority were Singaporeans, including students, and residents returning from countries locking down their borders. These "imported" cases exceeded locally transmitted cases on most days.

Amid the worry about imported cases, a fourth wave - a tsunami, really - emerged around March 30. Foreign workers started coming down with the virus, following extensive testing.

Meanwhile, cases continue to pop up in the local community, most recently at the Institute of Mental Health. Overall, however, the local community spread appears to be on the decline, though no links have been traced in some cases.

SAVING LIVES & LIVELIHOODS

For governments everywhere, the pandemic is not just a health crisis but also an economic one.

To contain the virus and save lives, they must restrict movements and economic activity. To relax too soon would risk infections returning and spreading.

Since the pandemic, trade and investment, the lifeblood of an open economy like Singapore, has been choked. Tourism is non-existent.

Domestic economic activity has slowed since the circuit breaker measures came into effect on April 7. The period was extended from May 4 to June 1, with gradual easing in some areas announced yesterday.

The multi-ministry task force managing the pandemic has had to calibrate its measures on both the health and business fronts.

The task force is chaired by Health Minister Gan Kim Yong and National Development Minister Lawrence Wong.

Deputy Prime Minister Heng Swee Keat, who is also the Finance Minister, is its adviser. Major decisions are deliberated at Cabinet level, which Prime Minister Lee Hsien Loong chairs and where other senior ministers share their expertise.

The task force is supported by civil servants and medical professionals, and also takes guidance from medical and research experts led by Chief Health Scientist, Professor Tan Chorh Chuan.

DPM Heng says strong measures, including the circuit breaker, have to be taken to protect lives. These have had an economic impact.

"Some have characterised the choices we had to make as a trade-off between 'protecting lives' and 'protecting livelihoods'," he tells Insight.

"But this is a false dichotomy. If we do not take strong measures to contain the virus now, the situation can easily escalate and the economic disruption would be much more severe then.

"But if everyone cooperates fully during this circuit breaker period, we can break the chain of local transmission and resume economic activities in a calibrated way."

Mr Wong believes the majority of Singaporeans understood the rationale behind the circuit breaker measures and did their part to comply.

"But not everyone can adjust to the requirements. There are very real social and economic costs. Jobs and livelihoods are at stake," he says.

The impact is likely to be felt disproportionately by the lower-income and vulnerable groups, he adds. And being cooped up and isolated at home for long periods will also not be good for their health and well-being.

"We considered very carefully before we decided to proceed with the circuit breaker and then to extend it for another month," he says.

"We knew that businesses and workers were already hurting greatly. But in the end, we decided that we had to proceed, so as to break the transmission chain and stamp out the virus."

At the same time, he points out, the Government has drawn on the reserves to help Singaporeans tide through this period. Since February, DPM Heng has announced $63.7 billion worth of support for workers, companies and households.

Policymaking is challenging because the virus is new and scientists are still struggling to understand it.

"In a crisis like this, we have to deal with fog-of-war decision making," says Mr Wong.

"We have to make consequential decisions within a very short period of time, with not a lot of data and information on hand. And these are important decisions that impact people's lives."

Openness and transparency are crucial in a health crisis.

Minister for Communications and Information S. Iswaran says Singapore has had to adapt its measures as it learns more about the virus from the evidence, the science, and the experience of other countries.

"Against this backdrop, we have done our best to explain the rationale for the measures, and any changes we have had to make, in a transparent manner in order to build public trust and social cohesion," he says.

"To succeed in this battle against Covid-19, we all need to know what we need to do and why we need to do it."

THE MEDICAL FIGHT

Because of Singapore's experience with outbreaks like the severe acute respiratory syndrome (Sars) in 2003 and H1NI in 2009, the Republic had infectious disease protocols in place when China announced the virus to the world on Dec 31.

By Jan 2, temperature checks had been set up at checkpoints for incoming flights from Wuhan, and doctors islandwide alerted to watch out for pneumonia patients with a travel history to Wuhan.

Contact tracing systems were in place and the newly built 330-bed National Centre for Infectious Diseases in Novena, officially opened just last September, was at the ready.

In the weeks that followed and as infections rose, more measures were rolled out progressively, including border controls and quarantine orders, culminating - for now - in the circuit breaker measures.

Prof Tan, who was director of medical services during Sars, says the most important takeaway from that period was experience.

There are now many individuals, from administrative leaders to medical professionals and front-line workers, who had gone through an epidemic.

They have the confidence and the knowledge of what to do - including the use of protective gear - which has led to somewhat less anxiety, he tells Insight.

In the early months of Covid-19, Singapore was held up as a model of virus detection, both by epidemiologists and the world media.

A widely quoted report by epidemiologists from the Harvard T. H. Chan School of Public Health in February described Singapore as "a gold standard of near-perfect detection".

But the new virus was not so easy to beat.

"It's actually a virus that's been designed to be difficult to control," says Prof Tan.

When news first emerged of its existence, the virus was thought to have initially jumped from an animal to man but with limited human to human transmission.

"At that point in time, it wasn't such a big worry because you've seen this also with bird flu and others, where there's no efficient transmission between people," he says.

"But once the reports started that human to human transmission was occurring, and clearly was quite efficient, then that was the part where we all got worried."

Worse was to come.

Studies then started showing people with mild or no symptoms spreading the virus, indicating some asymptomatic spread.

Prof Tan notes that the amount of virus shed by patients is highest very early at the onset of disease.

"All these things make it very hard to control," he says, "and which is part of the reason we have difficulty in closing down on outbreaks as quickly as we'd like to be able to do."

THE MASK ISSUE

The emerging knowledge of the coronavirus was a reason Singapore's stance on the wearing of masks changed.

Early in the outbreak, people started hoarding masks. The Government took the decision to distribute four surgical masks to each household, to be used if a person was unwell and on the way to see a doctor.

In public messages, the focus was on how masks should be worn only by those who are unwell or in close contact with infected people.

Wearing a mask when well also gives a false sense of security, ministers said, as they emphasised personal hygiene instead. There was also the issue of how stocks of surgical masks had to be preserved for medical use.

On April 3, PM Lee announced that mask-wearing was no longer discouraged due to new evidence of asymptomatic transmission and the possibility of undetected cases in the community.

Mask-wearing when stepping out became mandatory from April 14.

Asked about this, Prof Tan says the Government has been taking an evidence-based, data-driven approach.

At the point when advice was first given, it was widely accepted that coronavirus transmission started only when a person was symptomatic.

The picture changed with convincing evidence that pre-symptomatic transmission could occur.

"It means that... even if I'm a very responsible person, I can't even tell whether I'm infected, in which case then it argues for universal mask usage as a way to... reduce the risk of spread."

That said, while an unwell person wearing a mask helps protect others from his infected droplets, the use of masks to protect yourself from other people is still not a settled issue.

"Certainly, cloth masks and so on are probably not very effective," he says. "Surgical masks are better but then you have to be properly trained, you got to use it consistently, you got to use it properly and then you got to combine it with hand hygiene, etc."

PROBLEM AT THE DORMS

More than the issue of masks, the explosion of cases at cramped, crowded foreign worker dormitories has led to questions about the Government's handling of the pandemic.

Why had the Government allowed such poor conditions to linger? Why hadn't it acted earlier to prevent the outbreak among the workers? If it had, wouldn't the rush to find alternative accommodation for the workers been avoided?

On the poor conditions at dormitories - a longstanding issue in Singapore - Manpower Minister Josephine Teo says: "There will be a time to look back properly and follow up on the lessons learnt."

For now, the focus is to look after the workers and make sure they stay healthy, she says.

She points out that MOM has been guided by medical evidence.

Up till mid-March, there was no evidence of widespread transmission among the migrant worker population.

There were no clusters except for a small one in mid-February at Seletar Aerospace Heights.

There were no clusters at the dormitories either, and the medical consensus then was that asymptomatic transmission was unlikely.

She says the foreign worker population hadn't been ignored.

The first thing the Government did upon news of the virus was to progressively limit the inflow of workers to minimise the risk of imported cases.

From late January, MOM told dormitory operators to be more vigilant. Materials were produced in the workers' native languages to encourage them to take steps to protect themselves.

Non-essential facilities like gyms and TV rooms were also closed, meal times and recreational hours were staggered and intermixing between blocks stopped.

MOM enforcement officers also worked weekends to discourage large congregations at popular hangouts.

Mrs Teo says epidemiological findings provide some preliminary clues on the infection among the workers.

A good number of infected dormitory residents were linked through common worksites. Workers from different dormitories may have also gathered during their rest days to socialise and shop. Back in the dormitories, they socialised with other friends, cooking, eating and relaxing together.

"Despite the safe distancing measures in place then, the virus spread in the dormitories much like how it had spread among housemates, friends and the community," she says.

"So it's not clear that measures at the dorms alone would have made enough of a difference. Interventions were probably needed at workplaces and even on the social front. The three must come together, as they do now."

THE ECONOMIC FIGHT

On the economic front, the Government has rolled out a list of help.

Key in DPM Heng's $63.7 billion package is the Jobs Support Scheme where the Government pays out 75 per cent of wages for April and May on the first $4,600 of a worker's gross monthly pay, and at least 25 per cent for a further seven months, depending on the sector.

There are also measures, like for the self-employed, and Mrs Teo points out initiatives like the SGUnited Jobs Initiative which lists readily available jobs.

For Trade and Industry Minister Chan Chun Sing, keeping Singapore's supply chains robust and resilient has been a major preoccupation.

The Government has to constantly review its plans to stay "two steps ahead" of the rapidly evolving challenges, he says.

A number of agreements have been signed with other countries, including a Joint Declaration with New Zealand. This saw Singapore receiving food supplies from New Zealand and the Republic helping facilitate New Zealanders making their way home and with sourcing for medical supplies.

In the short term, the key focus for the economy continues to be preserving jobs and ensuring businesses have access to credit lines and cash flow. "Our aim is to be among the first off the block when the recovery comes," he says.

The next 100 days will remain difficult on both fronts.

Prof Tan warns that the coronavirus "still has many tricks up its sleeve and we have to be really very vigilant".

Health Minister Gan gives this assurance: "We will spare no effort to contain the situation and keep our people safe. This has been our priority from the start of this global pandemic, and will remain so."

In his May Day message, PM Lee said circuit breaker measures can be eased after the number of new cases are brought down, and Singapore can then progressively restart the economy. But Singapore must proceed cautiously, with safeguards, so infections do not flare up again.

He also urged employers and workers to take a longer-term view.

"Workers must accept wage sacrifices to keep businesses going. And employers must make every effort to keep their workers, and help them through this difficult period."

Over at McDonald's, the company announced last week that although it can restart operations on May 4, it was extending its closure for a little longer, for the safety and well-being of workers and customers.

As for the seven employees with Covid-19, there's some good news.

Its spokesman tells Insight that none was seriously ill.

One is fully recovered and resting at home, and the other six are on the road to recovery.

@STsumikotan

• Additional reporting by Timothy Goh