Things have turned quickly for the worse in Singapore, one of a handful of countries that had been praised for handling this crisis well. In contrast to many other places, Singapore’s suppression strategy until recently was focused on quarantine measures that began on January 21 that relied heavily on testing and contact tracing to discover community transmission clusters. Schools were not closed and ‘shelter in place’ lockdown orders were not issued because it appeared the strategy was working. However, starting at the end of March, Singapore’s confirmed case trajectory started going exponential with a series of highest daily records. A threshold-based partial lockdown order went out on April 3rd.
READ: Our Imperial Report explainer describes how this kind of ‘trigger’ process works.
As of 13 April, Singapore has seen 2,918 cases of COVID-19, with 2,323 current active cases. Of those active cases, 1,158 are hospitalized as stable, 29 are critical, and 1,165 are recovering in isolation. 586 have recovered, while nine have died directly from COVID-19. The largest spike in cases occurred on 13 April, with 386 new cases, indicating the highest daily total may be yet to come. The first case was reported on 23 January when a male, age 66, arrived from Wuhan. Singapore immediately implemented contact tracing to identify possible clusters related to the first case.
Singapore’s Second Wave
In addition to testing and contact tracing, most industrialized Asian countries have increasingly relied on strict travel restrictions and/or quarantine measures for arrivals to cut off new imports. Singapore restricted Wuhan arrivals on January 29th, as the number of infections reached 10. These measures came only days after Taiwan and Hong Kong’s similar measures, with lockdowns inside China dramatically reduced exports by this time. From January through early March, Singapore largely tracked alongside Hong Kong and Taiwan as global First Wave success cases.
By April, however, Chinese imports were near the bottom of the Top 15 list of detected imports for all three. Singapore started detecting imports from Indonesia and later Malaysia, both of which have substantial cross-border traffic with Singapore and are now the country’s third and fourth largest source of imports. Compounding this was the real Second Wave in the form of returning students, travellers, and businesspeople from the US and Europe (the US and UK now rank in the top two COVID-19 exporting countries for all three now). All three have been eight times as many imports from the United States as they originally got from Wuhan in January.
Singapore was the first country to begin implementing contact tracing via serological testing. They have also been ahead of many other countries in using technology for contact tracing. The expansive tracing model Singapore is using allowed for spotting and identifying several clusters from imported cases in late February. The problem with Singapore’s intent focus on imported cases from Asia, however, was a delay in spotting imported cases from countries which were under testing, chiefly the United Kingdom and United States. When this became apparent in contact tracing studies, mandatory quarantine was established for all returning residents, with a significant number of students from the UK and US eventually presenting mild symptoms.
Even with stricter quarantine measures, local clusters were still breaking out, most which were related to dormitories, schools, churches, or construction sites. The spark in local clusters led to the raising of the DORSCON level from Yellow to Orange, implicating continuous intervention to stop the spread. Serological testing on the scale Singapore has implemented is currently being researched globally, but not thoroughly practiced in western countries. The practice is key to identifying people who have SARS-CoV-2 antibodies, possibly allowing them back to work and showing which personnel can safely work on the front line. A combination of the RT-PCR test for infection and the serological testing for immunity is key to developing further public policy for June through August.
Yet, a serological test would not be the end of research matters, and it has not been for Singapore. Research suggests recovered patients will be immune, but that is not still being definitively determined. Furthermore, at time of writing, there are 94 cases pending contact tracing, as the confirmation test, and the subsequent tracing, demands time. There are two tests developed in Singapore, one with 90 percent sensitivity, and another that is the “gold standard”, but takes three to five days. Hence, there is lag time in identifying a possible cluster of cases.
The Limits of Contact Tracing
Unlike Hong Kong, Macau, Singapore neither schools or asked people to try to work from home until just recently. Like Taiwan, Singapore relied mostly on testing contact-tracing to fight COVID-19 without implementing domestic lockdown measures. However, Singapore wound up hey receiving a lot more imports than either Hong Kong or Taiwan: 592 cases with recent travel history, specifically from Malaysia and Indonesia. Contacting Tracing had a considerable effect on eliminating the possibility that these imported cases did not spark unmonitored clusters. There is evidence they might have overlooked transmission from pre-symptomatic cases. In China, pre-symptomatic transmission was estimated to be 12.6 percent, while in Singapore, initial levels of pre-symptomatic transmission were 6.4 percent.
As evidenced by hundreds of new cases everyday, there is a possibility pre-symptomatic transmission was not caught upon import, and lead to undetected and unmonitored local transmission. The reproductive rate in Singapore was also assumed to be below one, which would have biased investigators from spotting local transmission. This might have been the case in January and February, but not for the Second Wave that likely began in early March. The assumption the R0 was below one, however, was based on contact tracing, and not lockdown measures. This is important, as theR0 without lockdown measures could be as high as three to five; regardless of the exact number, it is higher than the seasonal flu r_0 of 1.3.
The other factor that must be considered is lag time. The timeline for a case to be symptomatic is up to 14 days, with a median of five days. While more research needs to confirm the viral timeline, the running hypothesis is serious cases will need hospitalization in the second week of disease, mild cases will begin recovery after 14 days, and death can take up to a month to occur. Hence, imported cases may turn into domestic spread that take up to 14 days to spot, with another two to three weeks for hospitals and statistical testing to see the increase.
Therefore, the implication is that Singapore assumed pre-symptomatic transmission was a benign problem – that contact tracing (i.e. catching imported cases) alone would maintain a domestically low R0 – that unknown sources were not a possibility, or not worth checking back on – and lockdown policy did not include the need to account for the lag in spotting cases. That is, the lag time implicated pre-symptomatic spread would readily occur during the vulnerable period with the government only locking down once numbers reflected this spread.
Singapore’s COVID19 Trigger
Thus far, Singapore has been following the Imperial College model as a trigger point for policy decision. The serological testing has been key to Singapore being a leading nation for reflecting the true number of cases, and thus allowing them to make appropriate decisions in accompaniment with the reality they are facing. However, there have been three glaring areas where Singapore may have ignored the Imperial College report: The above discussed lack of domestic lockdowns (broadly defined) and lack of early school closures. Cramped and unsanitary foreign worker dormitories, managed by the private sector and largely unregulated by the state, also played a role
Schools were not closed until 8 April, as the country has recently entered a “circuit breaker” lockdown. The Imperial College Model suggested that a third of transmissions occur at schools and workplaces. Unlike Hong Kong and Macau, Singapore did not proactively trace local cases, and while they can be praised on proactively tracing imported cases before the concept was popular globally, the government failed to take necessary measures to close down highly probable transmission points. Only a few clusters are related to schools, but distance-learning measures may have added additional punctuality to stopping domestic spread. Other research suggests that schools are not potential high infection points, and Singapore’s lack of children and young adults infected support this. However, schools and universities often host large gatherings – gatherings which are potential infection points.
The second area of criticism of Singapore’s approach has been the foreign worker dormitory infections, which is the leading source of clusters. These dormitories often provide little ventilation, are extremely enclosed, packed with double-decker beds, boarding 12 to 20 people per room and have poor toilet sanitation measures. Poor plumbing is a possible condition for creating a high infection point, making living conditions for impoverished workers especially deadly. Considering foreign workers are often the overlooked class in Singapore, they are also the least likely to get tested until it’s too late and transmission in their circles begins. This was exemplified when two dormitories (S11 and Westlite Toh Guan) housing 20,000 people were sealed due to widespread transmission. Two more dorms were put under isolation, involving three new clusters on April 11th.
COVID-19’s Economic Impact
The outbreak among foreign workers also raises questions about their position in a contracting economy. Even if Singapore recovers quickly due to tracking and tracing as an island nation, there could be fewer jobs once the workers are healthy. After a 2.2 percent contraction in Q1, the hardest hit sectors were construction and service – the most prevalent jobs for foreign workers. Singapore’s Foreign Minister Vivian Balakrishnan is already planning for the economic contraction to last a year, with other data estimating a contraction worse than the 2003 SARS economic slide. Minister Indranee Rajah has added there is no model or past experience to provide an estimate or guidance for economic contraction.
In response to the economic slide, Singapore has already set aside 1.9 billion SGD. Part of the programs will include industry and innovation initiatives, extended training for job skills, and sanitation/hygienic efforts which will be co-funded by the government. Additional monetary plans have been extended for self-employed individuals, a demographic which will receive specific support from the government per Josephine Teo. In the coming days, additional plans could be extended to aid foreign workers. Much of the monetary plan may be put on maintaining and creating advantage for Singapore as a finance, technical, and logistics hub; hence, the heavy-handed efforts to include the private sector in combatting the virus. The month of April may start to show which sectors will be most vulnerable, as Singapore’s “circuit breaker” measures only shut down non-essential businesses this last week.