Effective Containment — How South Korea’s First Coronavirus Wave was Halted

“Testing on its own will not stop the spread of SARS-CoV-2. Testing is part of a strategy. The World Health Organization recommends a combination of measures: rapid diagnosis and immediate isolation of cases, rigorous tracking and precautionary self-isolation of close contacts.” — COVID-19 Epidemic in Switzerland.

“South Korea has emerged as a sign of hope and a model to emulate. The country of 50 million appears to have greatly slowed its epidemic … Behind its success so far has been the most expansive and well-organized testing program in the world…” — Science Magazine.

“We acted like an army.” — Lee Sang-won, an infectious diseases expert at the South Korea Centers for Disease Control in a statement to Reuters.


If U.S. leadership, under Trump, failed to initially prepare for, recognize, respond to, and effectively communicate to the public on the issue of COVID-19, there was a whole new set of failures surrounding the issue of infectious disease containment. Specifically involving the federal provision of enough tests to the public and to various infectious disease and emergency response agencies to stop a rapidly mounting COVID-19 threat. This failure is a part of the larger response failure by Trump and his administration. In particular, this containment failure was so crucial that it deserves a separate mention (next chapter).

But before we dig into the Trump Administration’s specific failure to provide the tests needed to conduct a successful disease outbreak containment, to gain an accurate picture of the disease outbreak during mitigation, or to provide any hope for an effective reopening of the economy following any successful mitigation, it’s helpful to look at the response of a nation that did manage a successful containment of COVID-19’s first wave. For a rapid response by South Korea, primarily through mass production of tests and subsequent contacts tracing and isolation, squashed what could have been a much more substantial first wave outbreak and ultimately managed to greatly limit new daily cases.

Testing and Containment

Detection and identification of cases, testing which according to CDC is an essential tool for detecting infectious agents, isolation of confirmed cases, contacts tracing, and isolation of confirmed contacts. In a single sentence, this basically defines a strategy of novel infectious disease outbreak containment (based on CDC’s after action reports on SARS response and CDC’s FAQ on SARS).

Epidemic phases and response

Epidemic phases and response interventions. Detection and containment are key responses. Availability of testing is critical for this phase of infectious disease response. Image source: World Health Organization.

It’s used when there’s a new illness outbreak that can’t be effectively treated or cured and when that illness represents a significant threat to life, well being, and a functioning society. In recent years, detection and containment was effective in halting both the first SARS outbreak in 2002 and 2003 and the major Ebola outbreak of 2013-2016. Containment is itself only as effective as the ability to positively identify — often best done through symptoms screening by astute healthcare professionals and testing — a majority of the active cases and to, through contacts tracing, identify each person contacted by the infected individual(s) and to isolate all those involved. If there are not enough tests to measure the number of people infected, if the information management resources do not exist to trace contacts, and if isolation of cases and contacts is not conducted in an effective manner, then containment is unlikely to succeed.

Containment should not be confused with mitigation. But it can be used alongside mitigation as part of a comprehensive strategy of disease response. Mitigation is a strategy to be used either in conjunction with containment of a large outbreak or when containment fails and a widespread outbreak begins to result in disease amplification and/or presents a threat to the effective functioning of healthcare infrastructure. Mitigation often involves social distancing — which is, in effect, the pre-emptive isolation of large sections of society to reduce contacts and to slow disease spread (we’ll talk more about mitigation in a later chapter).

Contact Tracing

Testing and positively identifying cases enables a second aspect of infectious disease containment — contact tracing. This practice can identify cases quickly and, in conjunction with isolation, prevent illness spread. Image source: CDC and CFCF.

Testing and containment is very important in its own right. It can stop an illness in its tracks. It can save thousands, tens of thousands, hundreds of thousands, or even millions of lives. In the present context of the COVID-19 pandemic, containment has succeeded where testing was widely available and when contacts tracing and isolation was conducted effectively. And in the worst outbreaks — such as in the U.S. — containment failed, in large part, due to lack of the capacity to conduct a large number of tests. This failure resulted in a greater outbreak which froze the economy and required large-scale mitigation to slow disease spread, maintain the ability of hospitals to function, and to reduce loss of life from millions to tens or hundreds of thousands.

South Korea — Learning Hard Lessons From MERS

The story of South Korea’s successful response to the first wave of COVID-19 pandemic begins back in 2015 when MERS was producing a global outbreak of new infectious illness. MERS was another novel disease similar to SARS in that it impacted the human respiratory system and resulted in high death rates. It emerged from yet another climatologically hot region — the Middle East. And MERS was still another novel coronavirus. One also with an ultimate origin in bats. However, MERS is thought to have a zoonosis due to harmful interactions between humans and camels. How MERS spread to camels from bats and then to humans remains somewhat unclear. Though it is thought that the consumption of poorly cooked camel meat is a likely vector for transfer of this new illness to human beings.

MERS was far more deadly than SARS — resulting in mortality in about 1/3 of those infected. Its geographic region of origin was the Middle East. And since the time when MERS was first identified in 2012, approximately 2519 individual infections have been reported on a global basis.


A map of MERS transmission and outbreaks. Human outbreak areas shown in red and blue. Note South Korean outbreak in upper right. Image source: WHO.

In 2015, South Korea had its own tough brush with MERS. At the time, a South Korean businessman became ill after a trip to three countries in the Middle East. He sought treatment at three South Korean health facilities before he was diagnosed with MERS and put under isolation. But his contacts over the interim period ultimately resulted in 184 MERS infections within South Korea and 38 deaths. During this period, South Korea conducted a major response effort to contain the horrifying illness. The prospect of a major epidemic sent alarm signals through the country, slowed its economy, and traumatized the public. In response, South Korea produced a, then major, testing, contacts tracing, and isolation response in order to contain the illness. In the end, over 17,000 people were quarantined in an effort that ultimately quashed the outbreak.

Alertness, Training, and an Early Response

Pneumonia-type illnesses appear to have ingrained themselves on the collective consciousness of South Koreans during recent years. The 2015 MERS outbreak was viewed by many as a wake-up call. But the earlier 2002-2003 SARS outbreak and a general understanding of the risks of new coronaviruses appear to have made their cultural mark as well.

Back in December of 2019, according to reports from Reuters, two dozen top infectious disease experts in South Korea conducted a tabletop exercise. The scenario was oddly prophetic — a family becomes infected with a pnemonia-like illness after a trip to China. In the scenario, the new illness could have been a new form of influenza or a coronavirus like MERS or SARS. The exercise left its mark. And the lessons learned from it would be crucial to South Korea’s rapid escalation.

Just one month later, South Korea was organizing a response to an actual coronavirus pandemic emerging from China. And they were about as ready as they would ever be due to a combination of preparation, concern, and apparent luck.  On December 30 of 2019, China and WHO collected and analyzed samples of the novel coronavirus and then communicated first findings. And on January 4th, just five days later, South Korea’s infectious disease experts had access to a test methodology to positively identify COVID-19 cases. This was three days before China had genetically identified the new virus, it was five days before Chinese scientists uploaded a copy of SARS-CoV-2’s genome into an international repository. On January 9th they began lab testing for COVID-19.

They’d learned their lesson from MERS — quick response was absolutely necessary. And top experts still had the recent tabletop exercise fresh on their minds. But they still didn’t have a commercial, mass producible, test. The early testing methodology was slow. It could only manage a small number of cases at a time. As the disease began to rapidly expand in China, South Korean infectious disease experts feared they’d need something that was easily replicated on a mass scale.

On January 27th, South Korean infectious disease control personnel had detected just four cases of COVID-19 but they feared an epidemic. And their fears were rational. They’d experienced the explosive growth of MERS just a handful of years earlier and experts were starting to get hints that COVID-19 was a deceptive illness capable of both eluding detection and rapid expansion without widespread testing and isolation. On the same day, South Korean CDC officials summoned 20 heads of the nation’s medical industry. Their goal — turn South Korea’s lab test into a mass-produced, easy to use, diagnostic test. Just one week later, a diagnostic test produced by one of these companies was approved by South Korea’s CDC.

Lee Sang-won, infectious diseases expert at Korea’s Centers for Disease Control and Prevention, noted to Reuters — “We acted like an army.”

From Testing to Containment — South Korea’s Close Call

The problem with containing a disease like COVID-19 is that it is capable of seriously explosive spread. A single person infected with this illness who gets into a tightly packed setting with a large group or that moves rapidly from person-to-person can become what in disease parlance is known as a super-spreader. On February 18, just 11 days after South Korea had approved a commercially mass-producible test for COVID-19, a woman presenting symptoms who would represent South Korea’s 31st official case tested positive.

She was 61 years of age and, like many of us, she was a social person who delighted in her community. Part of her community was a rather large mega-church — the Shincheonji megachurch in Daegu, about 240 kilometers southeast of Seoul. When her contacts were traced it was found that she attended two services — one on February 9th and another on February 16th. At the time, she was already feeling slightly ill. In the church — 500 attendees would sit, tightly packed, through each 2 hour service.

South Korea Coronavirus Cases

Infection curve for South Korea shows a major spike in cases during late February and early March, then a rapid flattening that experts attribute to mass testing and isolation enabled by widely available tests for people with symptoms. Image Source: Worldometers.

From February 17 through 29, South Korea experienced an explosion of cases jumping from 31 to 3150. The vast majority of these new cases came from members of the Shincheonji megachurch. At this point, South Korea’s outbreak was the largest outside of mainland China. It was an outbreak that threatened to overwhelm the nation of 51 million people. South Korea’s 130 disease detectives were initially swamped by the Shincheonij-centered outbreak. More than 80 percent of patients with respiratory symptoms from this single outbreak were testing positive and the resources of South Korea’s traditional CDC response force was chiefly focused on this one cluster.

South Korea’s disease response teams were reeling. And without the earlier prep-work, they would have surely failed. As it was, South Korea just barely responded in time to prevent a much larger outbreak.

Responsible Governance Leads to Disease-Fighting Success

South Korea’s fast-tracked testing, contacts tracing and isolation system arrived in late February and rapidly expanded into March. This fast-tracking provided a key new disease response capability exactly when it was needed. By the end of February, just as its outbreak was ramping up, widespread road-side testing centers were opened. These centers were specifically set up to manage infected persons. Staff had personal protective equipment (PPE). They’d been trained in proper infection containment and sanitation protocols. And, in total, these centers were capable of testing thousands of people each day.

Drive Through Testing South Korea

One of South Korea’s many drive-through testing centers. At this location, healthcare professionals wearing personal protective equipment (PPE) administer a COVID-19 test. Image source: Government of South Korea.

In addition, specialized government isolation centers were opened for persons infected with COVID-19 — adding an outside capacity that reduced stress to hospitals. People who tested positive were required to download an app on their phone that traced their past movements and contacts. These contacts were also required to download the phone app and to self-isolate. Violators of the self-isolation policy were fined a 2,500 dollar equivalent.

This larger second line of defense enabled South Korea’s health officials to capture cases and conduct larger isolation outside of the initial disease cluster. A massive public health defense infrastructure that effectively sprang up overnight in response to the illness. One that ultimately prevented larger spread, wider sickness, increased illness amplification and death, and a need for even larger resource allocation to fight the disease. A national resource that would prove crucial.

Looking at South Korea’s infection curve, you can see how effective South Korea’s policy of rapid response containment has been. The results speak for themselves. They should count themselves fortunate for the responsiveness and responsibility displayed by their national government and leading healthcare professionals. Their first wave infection curve would have been much worse without it. It could have looked like Italy, or worse, the United States.

(UPDATED — Clarification on South Korea research testing timeline vs China’s COVID-19 research and coordination with WHO.)

Up Next: The Trouble With Testing Part 1 — “No Responsibility at All”

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