Singapore will have to change the way it manages Covid-19 patients as the surging numbers are starting to stretch the capacity of the healthcare system, say experts.
What is more, the number of foreign workers infected is expected to stay high, at least for some days, said Associate Professor Hsu Li Yang of the NUS Saw Swee Hock School of Public Health.
That is because, given the incubation period, those who have already been infected before the current efforts to re-house them kicked in will start to fall sick.
The rise in these numbers can be halted only if the spread is contained.
Prof Hsu, who is both an infectious diseases expert and an epidemiologist, said the spread of the virus in dormitories "must be slowed or else there is a high chance that our hospitals will be overwhelmed, whatever we do".
His colleague at the NUS Saw Swee Hock School of Public Health, Associate Professor Alex Cook, said: "We could easily see 10,000 to 20,000 foreign workers infected by the end of the month if we do not put in place fast and effective measures ensuring actual safe distancing among the workers currently in the dorms."
SURGE IN CASES
Singapore started one month of circuit breaker measures on April 7 to try to reduce the spread of the virus in the community. The first day shops and offices closed and people were told to stay home, there were 106 new infections, including a few in foreign worker dormitories.
But before those circuit breaker measures could provide breathing space to the local community, the outbreak in foreign worker dormitories ran rampant and the overall number of infections shot up dramatically.
Yesterday, there were 623 new cases, with foreign workers making up the vast majority.
Fortunately, most foreign workers here are younger and in better health, so the number of those who may become seriously ill will likely be lower, said the experts.
How foreign worker cases could hit 20,000
Singapore has seen an almost exponential growth in the number of Covid-19 cases recently.
This is because the numbers are growing so rapidly that it is not a matter of adding to the previous total, but almost appears to be one of multiplying the total by some number each day.
Associate Professor Alex Cook of the National University of Singapore Saw Swee Hock School of Public Health, a modelling expert, predicts that at this rate, the number of foreign workers with Covid-19 could reach 10,000 to 20,000 by the end of the month.
Prof Cook said: "The human brain is not well designed to understand exponential growth because it grows so much faster than we expect."
As an example, he cited the story of a wise man who agreed to work for a king and asked to be paid in rice grains on a chessboard that doubled with each square - one on the first, two on the second and so on.
It may seem small, but there is not enough rice in the world to fill the 64th square, he said.
Prof Cook said exponential growth slows if there is herd immunity, meaning that if many people recover from Covid-19 and become immune from contracting it again, they become "wasted" in terms of viral spread - and will not count as a new case.
The other option is strong control measures like identifying and quarantining patients.
But he said: "At this stage, even a slower growth rate will still lead to a lot of infections."
But Prof Cook warned that should the workers be smokers or have high blood pressure, they risk falling critically ill if infected.
Also, as the total number of cases rises, those who need to be hospitalised will increase.
Professor Dale Fisher, a senior infectious diseases expert at the National University Hospital (NUH), estimated that between 5 per cent and 10 per cent of foreign worker cases would need to be hospitalised, and perhaps 1 per cent to 2 per cent would become critically ill.
This is lower than the population norm of 15 per cent to 20 per cent that fall seriously ill and about 5 per cent who might need intensive care.
Singapore had a total of 11,321 acute hospital beds at the end of last year, of which 9,400 are in the public sector. However, since January, when the first case of Covid-19 was identified here, non-urgent treatments have largely been postponed.
As a result of this, bed occupancy rates at public hospitals have gone down from around 90 per cent at the start of the year to about 75 per cent by last week.
That has freed up more than 2,000 public hospital beds. But with the large number of people infected this month, these beds are being filled up rapidly.
The number of Covid-19 patients hospitalised had shot up from 473 on April 3 to 1,886 by Thursday.
Private hospitals, which have slightly more than 1,600 beds, are also helping to care for Covid-19 patients.
There are another 2,000 beds in community hospitals, of which almost half are in the public sector. These can offer some beds for recovering patients to free up capacity in acute hospitals.
Taken altogether, they might still not be enough for the rising number of Covid-19 patients. However, about four in five of these patients usually get just mildly sick.
A small number do become critically ill.
Singapore has about 1,100 critical care beds in all, about equally divided between intensive care (ICU) and high dependency. The Ministry of Health (MOH) said that only the ICU beds have ventilators that critically ill Covid-19 patients might need. These beds are needed by both normal patients as well as those infected by the coronavirus who are critically ill.
So far, the number of Covid-19 patients who need intensive care has remained relatively low, with 23 currently listed as critically ill.
But Prof Fisher said: "If 20,000 get infected, they will need at least 200 ICU beds, and statistically there may be 40 deaths."
Prof Hsu said Singapore needs "to be agile and creative about how we deploy existing manpower and resources", such as building additional facilities and training people to care for the large influx of mild Covid-19 cases.
All three experts said what is needed is a good system for isolating and monitoring Covid-19 patients who are mildly ill outside of hospitals.
Prof Fisher said both healthcare facilities and manpower are still coping, but starting to feel the strain.
Manpower is stretched as the three public healthcare clusters are also providing onsite medical care for the foreign workers in the dormitories as well as other locations they have been re-housed in.
Prof Hsu suggested: "Covid-19 cases should be triaged and those with minimal risk of complications should be sent to community isolation facilities immediately, rather than face a period of observation in an acute hospital.
"They will need to be monitored more carefully at the facility so that they can be rapidly transferred to an acute hospital in the rare event that they deteriorate."
Prof Cook said the current procedure of moving the less serious cases from hospital to other facilities, such as the Expo, may not be sustainable for long. He said: "We will have to accept that milder cases be managed outside of the formal healthcare environment."
Prof Hsu said it is important not to let the healthcare system be overwhelmed, as that would impact other patients.
"There will be delays in follow-ups and treatment for chronic medical conditions, including cancer," he said. "Surgery may be delayed or postponed, and ultimately, there may be more preventable deaths as a consequence. We hope never to reach that situation."