Case Study: South Korea 2020

As COVID-19 cases in the US continue to rise, we can look to other countries that are farther ahead in their epidemics as sources of instruction. Of particular interest is the case of South Korea. SK is a democratic country, with largely privatized healthcare and strong corporate research presence, much like the US. Cases in SK initially grew exponentially but have flattened in recent days with extensive efforts to scale up testing, perform contact tracing, and promote social distancing, without nationwide lockdown. Here we present an overview of SK’s interventions.

Italy and SK had initially shown similar trajectory in the rise of cases, however, SK in recent days has plateaued. The US is about 1-2 weeks behind SK and Italy (fact and figure source).

Strategies for Testing

Both the US and SK detected their first case of COVID-19 on January 20. In response, the SK government urged SK medical companies to immediately develop a testing kit. By February 4, SK approved the first testing kit, when only 16 cases had been confirmed in SK. Rapid approval was possible because of the emergency use authorization policy enacted after the MERS outbreak in 2015. This cooperation between the private biotechnology sector and government led to efficient roll out of its extensive testing capacity. As of mid-March, four biotech companies are producing testing kits around the clock to meet the demand, distributed to over 600 testing centers. All labs upload their results to the shared database and are reported to KCDC, which then releases daily reports detailing the epidemiologic data to the public. SK’s maximal testing capacity is ~22,000 tests per day. Why is extensive testing so important? It means that infected individuals and contacts of those individuals can be isolated and/or treated with minimal delay. This drastically reduces opportunity for transmission, thereby decreasing Re.

In addition to scaling up testing capacity, SK has come up with creative testing strategies to reduce risk of contamination, reduce risk of cross transmission, increase efficiency, and prioritize safety of healthcare workers.

  • Automatic testing: Done by a diagnostic machine, rather than by a lab technician. This decreases risk of contamination, risk of transmission to healthcare workers, and allows for faster turnaround of results.

  • Drive-through testing: Patient stays in their vehicle with recirculating air turned on to minimize risk of transmission to healthcare workers. (Think of it as a makeshift negative pressure vehicle.) This method is much faster than point of care testing, because time is not wasted in disinfecting the facility and reduces risk of cross transmission. The results are texted to patients the next day. As of mid-March, SK has 43 drive-through testing centers, part of more than 600 testing sites.

  • Telephone booth testing: For those without access to vehicles. Nasopharynx and oropharynx swabs are collected while the patient is in a negative-pressure telephone booth sized room, which takes only two minutes to disinfect. This methods has the same advantages as drive-through testing. Link to a video.

Image Source: AFP Image Source: CGTN

Strategies for Containment: Contact Tracing, Quarantine, and Treatment

With a large capacity to test individuals, SK can offer testing to individuals who have been in contact with a confirmed case, even if asymptomatic. When an individual tests positive, thorough contact and location tracing is done through patient interview, credit card use history, CCTV (surveillance camera), and mobile phone location. These locations are disclosed to the public and emergency text alerts are sent to those in the region, so that people can learn whether they came in contact with a confirmed case. All identified close contacts are put under quarantine and monitored daily for developing symptoms. Those who are required to self-quarantine or self-isolate are required to download an app that tracks their location to ensure adherence. Those violating self-isolation can be fined up to 10 million won (~$8,000 USD) and up to one year of imprisonment.

These interventions have allowed for detection of mildly symptomatic to asymptomatic cases, which have contributed to a low case fatality rate of 1.3% in SK in comparison to the 4.8% global average as of March 31st. CFR should not be used to estimate risk of death during an outbreak due to the propensity to underestimate, given the time delay from case confirmed to death confirmed. However, the low CFR in SK may reflect the success of their extensive testing regimen that can detect cases that are missed in other countries without the same testing capacity. Determining asymptomatic carriers and isolating those individuals may be of great importance as increasing evidence (1,2,3,4) suggests that asymptomatic carriers may be a significant vector for transmission. Furthermore, the South Korean health officials recommend wearing masks to all citizens to prevent the spread of COVID-19, and the public embraces mask-wearing. To prevent shortage, the government has taken over the production, distribution and sales and began rationing the masks.

In addition, the government bears the cost of testing and medical care received for COVID-19. It is free regardless of immigration status for anyone with doctor’s referral or contact with an infected person. Those required to quarantine are provided food and other essentials via package deliveries, paid for by the government. This decreases barriers for those of low socioeconomic status, helps curb the panic, and allows for individuals to adhere to strict quarantine.

South Korea’s extensive testing and contact tracing means that areas of outbreak can be recognized early and efforts can be deployed and concentrated to those hotspots to contain the spread. This minimizes the economic and social disruption of nationwide lockdown.

Thought question:

  • What factor(s) may contribute to differences in case fatality rates between countries?

Strategy for Mitigation: Social Distancing

Using aggressive testing and contact tracing measures, SK had been controlling COVID-19 cases since their first reported case on 1/20/2020 until patient 31, deemed a “super spreader,” who tested positive on 2/18/2020. As shown in the figure below, South Korean cases spiked after the 31st patient who had attended mass religious gatherings, coming into contact with more than a thousand people. As of March 25th, this cluster accounts for 55.6% of the confirmed cases in SK. Large mass gatherings in closed, confined spaces have led to massive increases in cases. This stresses that public participation in social distancing is critical for reducing Re, lengthening doubling time, and, thereby, flattening the curve.

Unlike China, SK has not implemented domestic travel bans and did not immediately ban travel from China at the beginning of the outbreak. Instead of a lockdown, South Korea has focused on engaging the public to practice social distancing in addition to cancelling large events, school openings and religious gatherings. While the number of new cases have decreased consistently, there are still clusters of new cases reported. These clusters have been attributed to large gatherings in confined rooms such as churches, call-centers (where large groups of people work in close proximity without wearing masks so they can speak clearly on the phone), internet cafes, hospitals, and gym facilities.

Situation in South Korea as of 4.16.20

Green bars: number of new cases per day; Blue curve: cumulative cases.

As of April 16th 2020 (source: KCDC)

As evidenced by the figure above, numbers of new cases per day have been consistently declining and stabilizing. The slope of the cumulative curve has been decreasing, no longer showing an exponential growth pattern, suggesting that SK may have been successful in reducing Re. While SK's health minister has said he is hopeful that SK has passed the ‘peak’ of the outbreak, it remains to be seen whether this depression is temporary. As stated earlier, the majority of the population has not been infected and therefore remains susceptible. This is particularly challenging given differences in intervention across countries responding to this pandemic, such that the risk of reintroduction from different locations persists. As of April 1st, SK imposed a mandatory 14-day quarantine to all (Koreans and Foreigners) arriving from overseas in an attempt to curb the rise of imported cases. As of April 4th, SK has extended the social distancing campaign to April 19th. Given the long tail of the cases that have followed the peak, the period for contact tracing has also been extended to 2 days before onset of symptoms from 1 day. How SK continuously adapts its control measures to respond to new infections will be a useful case study for other countries.

On April 15th, South Korea held their National Assembly election as scheduled. SK was the first country to hold a nationwide election during the coronavirus pandemic. Extensive safety measures were put into place to prevent another outbreak. All polling stations, which were disinfected regularly, were equipped with hand sanitizers, plastic gloves, non-contact thermometer, and separate polling stations designated for those with elevated temperatures. In order to vote, one had to wear a mask, stand at least 3ft away from others, have their temperature taken, sanitize their hand, and wear the provided plastic gloves. Even those in mandatory quarantine were able to cast their ballots at a restricted time when polling centers were closed to the general public. In addition, SK expanded early in-person and mail-in voting options to reduce crowding. SK had a record turnout of 66.2%, meaning more than 29 million people casted their ballots. Yet, their new cases per day have remained under 20, giving hope to other countries considering elections that democratic right to vote does not have to be compromised during the pandemic if protective measures are taken along with baseline of widespread testing, contact tracing and strict isolation of suspected cases.

As of April 30th, SK reports 4 new cases, all of them being imported cases. This is the first day since January 20th, where SK reports 0 infections acquired within the country.


South Korea and other Asian countries experienced the MERS outbreak in 2015, which contributed to increased preparedness for this pandemic. Although more time and monitoring is needed to determine whether SK has been able to suppress the COVID-19 outbreak, current trends suggest that their strategies of public transparency, civic awareness and responsibility, cooperation between the private sector and the government, decreasing barriers, and widespread testing has led to slowing the outbreak.

Thought Questions:

  • What strategies to reduce disease spread and case fatality rates can we implement in the US?

  • As future physicians, how could we advocate to increase preparedness for the next pandemic?

Supplementary Reading: