South Korea's contact tracing sheds light on extensive efforts to slow spread of COVID-19

SEOUL, South Korea -- Contact tracers in South Korea are working around the clock to do anything they can to mitigate the spread of COVID-19. From being on the phone all day to questioning COVID-19 patients about the places they have been to interrogating people about who they have been in contact since their first symptoms. Their work never stops.

Per one confirmed patient, contact tracers have to fact check between 10 to 20 traces and, when basic information is confirmed through a phone call, they have to follow that up in person to see if the representations that were disclosed were accurate.

It even sometimes takes replaying surveillance camera footage, speaking to witnesses and doing everything possible to collect all of the breadcrumbs a COVID-19 patient has left on the trail -- just like a detective.

South Korea has one of the most vigorous contact tracing systems in the world and authorities collect every piece of personal data possible to find any connecting link between COVID-19 patients in order to slow down the spread of the pandemic. Contact tracers will also call anyone who has been in contact with a patient and advise them to self-quarantine and get tested preemptively.

On average, from the week between Dec. 2 to Dec. 8, 584 people were confirmed with COVID-19 each day last week in South Korea.

At Gangnam Public Health center, which handles the largest number of COVID-19 tests each day in South Korea, there are four doctors -- officially called Epidemics Intelligence Service (EIS) officers -- who make the initial phone call to COVID-19 patients. They are in charge of collecting sensitive personal data such as medical hand family history.

"I collect a detailed path of movement since two days prior to the first symptom. Who they dined with, how much they paid for, who they live with at home and the workplace… every detail possible," Dr. Oum Seonmee, a dentist who was temporarily designated a contact tracer by authorities in April to cope with the rise in patients, told ABC News. "'Were you wearing a mask at the time?' is the key question."

It takes an entire public health center just to keep up with the vigorous contact tracing.

A total 305 government designated EIS officers often fall short of the manpower needed to keep the patients numbers in check. That is when civil servants are mobilized to take on the contact tracing role by making phone calls to contacts and going off to do field research for fact checking.

As soon as personal traces have been confirmed through a doctor's questioning, civil servants team up to do field research as contact tracers.

They verify the paths and cross check the testimony from patients and see if there's any additional people who need to be quarantined after contact -- and the penalty for not being truthful to contact tracers is heavy.

"We remind them that you could be fined up to 18,000 U.S. dollars or could be sent to prison for up to two years, under the Infectious Diseases Control and Preventions Act," Park Geon, a public nurse at Gangnam Public Health Center who has been working nonstop since the number of COVID19 patients has been on the rise, told ABC News.

Though some are unwilling to cooperate with authorities, there's little thought in South Korea that it could be an invasion of privacy.

"It was a relief to know that the government was actually tracking people," Steven Kim, a college student who received a call from the contact tracers in May, told ABC News. "[Authorities] offered me free testing even though I didn't have any symptoms and that was reassuring because there are many cases of asymptomatic patients and I could be one of them spreading the disease without noticing."

South Korean people in general take huge pride in what they achieved so far when it comes to containing the spread of COVID-19 and seem to appreciate the government's effort in heavy contact tracing. Frequently, there is a tendency to think that it was an individual's civic duty to cooperate with authorities on these matters.

"The majority of Korean people are supporting this type of very aggressive contact tracing at the potential cost or expense of privacy," Kwon Soonman, public health professor at Seoul National University, told ABC News. "There is a kind of group pressure that I should not harm my neighbor, because it's an infectious disease."

Experts agree, however, that contact tracing is only part of slowing down the pandemic and until a vaccine is accessible to everyone, contact tracing, along with masks and social distancing, will be key to protecting people from the pandemic.

ABC News' Joohee Cho, Aaron Kwon and HyunJoo Haley Yang contributed to this report.