There were two recent Coronavirus stories from Korea. A great case study showing why #Masks4All is important.
medium.com/@slowblogger/h…
medium.com/@slowblogger/h…
Let me take key points from my medium post, to make a tweet thread.
On April 8, a new Coronavirus patient was confirmed, the first new case in Yechon for over a month. It saw the last new case on March 6.
On April 8, a new Coronavirus patient was confirmed, the first new case in Yechon for over a month. It saw the last new case on March 6.
Yechon is a rural area. It is 660.7 km², which is larger than Seoul, but has only 55,000 people, in contrast to 97,760,000 in Seoul.
This patient, a female at 48, started having symptoms on April 3.
So, she had at least 5 days, during which she could have spread virus to others.
All her family members, husband, son, mother, were confirmed as infected.
So, she had at least 5 days, during which she could have spread virus to others.
All her family members, husband, son, mother, were confirmed as infected.
From April 1 to April 8, she visited her workplace office, supermarkets, public bathhouse, otolaryngologist’s, pharmacies, gas station, restaurant.
She wore a mask only at supermarkets and pharmacies.
Bathhouse was an infection hot spot in other towns. A big concern.
She wore a mask only at supermarkets and pharmacies.
Bathhouse was an infection hot spot in other towns. A big concern.
More problems came through her 19 year son. He hung out with friends without a mask at PC cafe, pub, etc. One was an election campaigner, who met many people.
The young men would not share where they went.
Officials had to use CCTV and GPS, more than doubling the time to map.
The young men would not share where they went.
Officials had to use CCTV and GPS, more than doubling the time to map.
From the mother and son, over 170 contacts were put into self isolation, and 39 new cases were confirmed including son's friends, contacts, indirect contacts and a person infected at the bathhouse.
Now it's Busan, the second largest city in Korea with 3,429,000 people in an area of 769.9 km².
It is much more dense than Yechon. Number of people per km² is 4454 vs. 83. Or 53 to 1.
It is much more dense than Yechon. Number of people per km² is 4454 vs. 83. Or 53 to 1.
A 58 year old man was confirmed as infected on April 18. But he felt sick as early as on April 8. So he lived normally with virus for at least 10 days.
He visited many places. High school (workplace), hospitals, community center to vote for election, restaurants, and church.
He visited many places. High school (workplace), hospitals, community center to vote for election, restaurants, and church.
His daughter seemed to have been infected first at a Coronavirus treating hospital, at which she worked as nurse.
She was at dormitory or the hospital most time, except for visiting parents a few times. But she worked at a large hospital, and used public transport.
She was at dormitory or the hospital most time, except for visiting parents a few times. But she worked at a large hospital, and used public transport.
The authorities had to test ~1200 contacts, including 149 who attended church service with the father and more than 800 employees at the daughter’s hospital.
A new wave was coming. Korea was about to explode again, right?
A new wave was coming. Korea was about to explode again, right?
No. Only 1 additional case was confirmed related to them.
Authorities attributed the amazing results to mask wearing. The father and daughter always wore masks at public places and public transport.
Authorities attributed the amazing results to mask wearing. The father and daughter always wore masks at public places and public transport.
Let's compare Yechon and Busan.
Similarity:
- Both started from a family. Main persons were mother and son in Yechon, and father and daughter in Busan.
- They lived quite normally until they were confirmed as infected.
Similarity:
- Both started from a family. Main persons were mother and son in Yechon, and father and daughter in Busan.
- They lived quite normally until they were confirmed as infected.
Busan disadvantage:
- Busan is 53 times more dense than Yechon.
- Busan pair spent ~2 weeks from infection to hospitalization, while Yechon pair ~1 week.
- Busan pair had much more contacts than Yechon. 1200 vs. 170.
- Busan is 53 times more dense than Yechon.
- Busan pair spent ~2 weeks from infection to hospitalization, while Yechon pair ~1 week.
- 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.
- 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, and Busan 1.
One official said, “These two cases showed extremely evidently how powerful the mask is.”
- Additional infection cases: Yechon 37, and Busan 1.
One official said, “These two cases showed extremely evidently how powerful the mask is.”
Both incidents were fully supported by Korea's well functioning test and trace. But the outcome was very different.
You cannot block infection perfectly with test and trace. You need a mass prevention tool. For now, we have lockdown and mask.
You cannot block infection perfectly with test and trace. You need a mass prevention tool. For now, we have lockdown and mask.
Until we have treatments and vaccines, let's all wear masks and transition wisely from lockdown.
#Masks4All
#Masks4All
I thank the father and the daughter in Busan who protected many people by wearing masks and gave us a great lesson. I hope they, as well as other patients in Busan and Yechon, get well soon.
I also wish the best for all patients around the world.
I also wish the best for all patients around the world.
97,760,000 should be 9,776,000. I am sorry for the error.
