In the early April in 2020, Korea was becoming more and more normal. Many Koreans seemed to feel more concerned with the national election on April 15 than with Coronavirus.

The number of new cases was decreasing steadily. In the first 7 days of April, it was 101, 89, 86, 94, 81, 47, 47. And the active cases on April 4 was 3,654, less than a half of the peak of 7,362 on March 11.

But it was not zero yet, which meant people were still getting infected everyday. Here are two of those stories.

Yechon and Busan in Korea

Yechon-gun, Gyeongsangbuk-do, Korea

Yechon is a small town.

Not in terms of territory. At 660.7 km², it is larger than Seoul at 605.2 km². But in terms of population. About 55,000 people live in Yechon, in contrast to about 9,776,0000 in Seoul. Let’s just say Seoul, which draws lots of additional people in the day time, has 200 times as many people in the same size of territory.

Yechon is a gun (pronounced more like ‘goon’), which is an administrative unit given to a rural area. Gun can be translated to town, village, or district. But it is similar to the county in the US in terms of administrative hierarchy. Two down from the country.

A new case confirmed after a month of peace

Among prominent news articles about the election, there was one about Coronavirus. News about Covid-19 has become a routine, but this one was quite alarming.

The patient (48, female) was confirmed on April 8, becoming the 7th Coronavirus case in Yechon. All of her family members, husband(48), mother(76), and son(19) were confirmed infected on April 9.

Until April 7, Yechon had only 6 confirmed cases, all found beween February 21 and March 6. It has not had any since then. All previous patients have been recovered, according to the Yechon-gun website. I have not found the date of recovery, but I presume mostly or all before April. You can imagine what people thought. Virus came back!

The 7th patient in Yechon started having symptoms on April 3, meaning she went around with infectious virus for at least 5 days.

From April 1 to April 8, she visited various places in Yechon.

Office of her workplace

Two supermarkets (masked)

Public bathhouse

Otolaryngologist’s office

Two pharmacies (masked at one)

Gas station (self-serviced)

Restaurant

She wore a mask when visiting supermarkets and once at a drugstore, but not at the others. Particularly worrying for the authorities was the bathhouse. She visited the bathhouse on April 2, and started having symptoms like fever on the next day. Bathhouses have been identified as hot spots of infection in other cases in Korea. People didn’t wear masks there.

Making it more troublesome, her 19 year old son, confirmed as infected, hung out with his friends without wearing a mask at various places including a PC cafe and a pub. One of his friends was an election campaigner, whose job obviously required meeting as many people as possible. The campaigner and contacts were put into self-isolation.

It was difficult to trace the young men’s contacts, as they were not very willing to share where they went and often changed timings. Without accurate statements of their whereabouts, the officials had to use CCTV and GPS, more than doubling the time to map their routes.

Over 170 contacts of the infected were put into self isolation. Shutdown of high contact businesses, including bathhouses and PC cafes, were recommended by authorities.

The results

As of April 25, 39 new cases were confirmed related to this incident. Many of them were direct and indirect contacts of the 19 year old, and some were contacts of a person infected at the bathhouse.

Busan, Korea

Busan is the second largest city in Korea, after Seoul. 3,429,000 people live in an area of 769.9 km². It is more dense than most other towns in Korea, and certainly much more dense than Yechon. In terms of the number of people per km², it is 4454 vs. 83. Or 53 to 1.

Warning bell rings loud

On April 19, multiple news articles wrote about two new infected patients, who were a father and his daughter.

From April 20, news articles were even more alarming. The two patients, 128th and 129th in Busan and a father(58) and his daughter(25), were found to have contacted nearly 1200 people. Some articles wrote that we might soon see another wave of epidemics coming out of Busan.

The father first felt sick on April 8 and went to see a doctor. I assume he was not tested for Coronavirus, as the hospital was not one of the officially designated testing places. Perhaps he was advised to be tested.

Anyway, he lived normally, until he finally went to a testing center on April 18. Wearing masks, he visited the following places during the time.

High school (his workplace)

Hospitals

Community center to vote for election

Restaurants

Church

It was thought that his daughter had been infected first at Busan Medical Center, one of Coronavirus treating hospitals, at which she worked as a nurse. Her routine during this time was pretty simple. She was at her dormitory or the hospital most of the time, visiting parents a few times.

But she had even more potential of becoming a super spreader. She worked at a large hospital, and she used subway and bus to visit her parents. Though she always wore masks at these places, she certainly had many contacts. And tracing people who used the same public transport is nearly impossible.

The authorities had to isolate and test about 1200 contacts, including 149 who attended the church service with the father and all (more than 800) employees at the daughter’s hospital.

The results

In contrast to the grim predictions, only 1 additional case was confirmed related to them so far. It is quite amazing, considering 1200 contacts.

The authorities gave credits to the father and the daughter who followed prevention guidelines very well. They particularly attributed the relieving results to mask wearing. The father and daughter always wore masks at public places and public transport.

Comparison of two incidents

Let’s summarize the two incidents out of Yechon and Busan.

Similarity

Both started from a family. Main persons involved were mother and son in Yechon, and father and daughter in Busan.

Both pairs lived quite normally until they were confirmed as infected.

Busan disadvantage

Busan is 53 times more dense than Yechon, making Busan more vulnerable to infection.

Busan pair spent about 2 weeks from infection to being hospitalized, while Yechon pair about 1 week. Busan had more potential for infection.

Busan pair had much more contacts than Yechon. 1200 vs. 170.

Behavioral differences

Yechon mother wore a mask only at some places. Her son did not wore a mask.

Busan father and daughter wore masks consistently, including father wearing one during the church service and daughter on the subway.

Outcome

Additional infection cases: Yechon 37, Busan 1.

As one of the officials said, “These two cases showed extremely evidently how powerful the mask is.”

Mask, the unsung hero

I feel strange, almost surreal, when the author apparently sees the prevalence of masks but treats it like a background.

Late last week millions of South Koreans queued patiently at polling stations to cast their votes for a new national assembly. If any uttered words of frustration from behind their masks, they were out of earshot of their fellow voters, kept at a distance by duct tape marking appropriate intervals. … Perhaps most striking is South Korea’s ability to tame the coronavirus without resorting to lockdowns of the kind imposed in the UK, Italy and France. In contrast to the panic-buying witnessed elsewhere, South Koreans for the most part stayed calm. There were no reports of hoarding, and the only people queuing were waiting to be tested or to buy face masks … or to vote. … “I’m a member of a community football club and we went out to play on Saturday for the first time in two months,” he said. “We were wearing masks while we played, and we were still worried about the coronavirus. But the weather was lovely. And I felt refreshed.”

Wear masks to win the fight

Both Yechon and Busan were fully supported by the national capacity of Korea. They were both rigorously traced and tested. But the outcome was very different.

However effective your test and trace, you cannot block infection perfectly. You saw it in the Yechon case. Singapore has experienced it.

The mass test, ideally testing everyone everyday, is not a reality for foreseeable future. Vaccine is not coming any time soon.

For now lockdown and mask are the only practical tools for protecting the mass public. But lockdown hurts the economy, the mask doesn’t. So, I believe we should all wear masks and gradually decrease lockdown depending on specific situations of a town.

Phased mass prevention strategies against Coronavirus

Many thanks to the father and daughter from Busan who protected many people. I wish they get well quickly. I wish the same for all the other patients in Busan, Yechon, the rest of Korea, and all over the world.

Let’s fight this together with masks on.