Status of COVID-19 and the role of Tohoku University - School of Medicine Dr. Hitoshi Oshitani
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Status of COVID-19 and the role of
Tohoku University
Tohoku University Seminar
May 26, 2020
School of Medicine
Dr. Hitoshi Oshitani
Difference between SARS and COVID-19
Deaths
Deaths
Severe
Severe
SARS
Mild
Asymptomatic
COVID-19
Difference in pathology between SARS and COVID-19
SARS COVID-19
1 pattern ３patterns
Severity−High Severity−High Severity−High Severity−Low
Infectiousness―Low Infectiousness―Low Infectiousness― High Infectiousness ― High
NEJM. February 19, 2020
DOI: 10.1056/NEJMc2001737
To KK et al. Lancet Infect Dis March 23, 2020
SARS COVID-19 Severe case COVID-19 Severe case COVID-19 Mild case
https://doi.org/10.1016/S1473-3099(20)30196-1 Pattern 1 Pattern 2
In case of SARS
Country A
Guangdong Hong Kong
Country B
MMWR May 9, 2003 / 52(18);405-411
• SARS also spread through clusters (superspreading events)
• Nearly all of SARS patients developed severe symptoms; thus, it was possible to trace majority of chains back to
Guangdong
• This enabled cutting off all chains of transmission
Basic reproduction number (R₀)
It is a number of how many people will be infected by a
single infected person ON AVERAGE. (In the image to the
left, 1 person is infecting 2 people, so the R₀ = 2)
If R₀ = 1 It won’t become an outbreak – steady state
If R₀ < 1 It won’t become an outbreak –
and virus will disappear
Transmissions increase. For example, if there are 10
generations of infections, 1 + 2 + 4 + 8 + 16 + 32 + 64
If R₀ =2 + 128 + 256 + 512 + 1024 = 2047 cases
The biggest mystery early in the outbreak
There were no transmissions from those who
had close contact with an infected individual
R0=0
Then why is it spreading?
This was being seen not only in Japan, but in other countries as well
Why is the disease spreading if most of the
infected individuals are infecting others?
Infected person 1
R0=（0+0+0+0+10)÷5=2
Infected person 2
Not infecting anyone else Unless 1 person is infecting many,
Infected person 3 while most are not infecting
anyone, the spread of the disease
Infected person 4 CANNOT be explained
We defined “cluster” as group of 5+
Infected person 5
infected individuals that have been
connected from cases that cannot
Infecting 10 people be traced
Frequency of secondary infected persons produced by a single person (n = 110)
空気のよどんだ閉鎖環境にいた
その他の環境にいた
頻度（⼈）
For these cases, if we can prevent a secondary infection,
R₀ will be less than 1 and can contain the spread
感染源1⼈あたりが⽣み出す2次感染者数
• Hokkaido University Professor Nishiura’s group’s analysis showed that the majority of those infected were
not infecting others
In case of COVID-19 • Say this is a cluster
In case of COVID-19:
Links that disappear, links that don’t disappear
• Even if the infected individuals in a cluster created secondary transmissions (family transmission, etc.), most chains of
transmissions are not maintainedIn case of COVID-19:
Links that disappear, links that don’t disappear
• The condition for the chains of transmissions to be maintained is for another cluster to form and that cluster to
continue on to form another cluster (chain of clusters)In case of COVID-19:
Links that disappear, links that don’t disappear
Symptomatic
Asymptomatic or mild casesIn case of COVID-19:
Links that disappear, links that don’t disappear
Invisible
link
Visible
link
Invisible
link
Symptomatic
Asymptomatic or mild casesIn case of COVID-19:
Links that disappear, links that don’t disappear
Symptomatic Possibility for increased transmissions especially if
there are invisible clusters (younger generations)
Asymptomatic or mild symptomsEpidemiological difference between SARS and
COVID-19
• SARS: Since most patients develop severe symptoms, all chains of
transmissions can be detected and be cut off, which led to a
successful containment
• COVID-19: Since most patients are asymptomatic or only develop mild
symptoms, it is effectively impossible to find all chains of
transmissions. It is impossible to contain it like SARS.Chain of transmissions that suddenly became visible (Feb 23) and set up of Cluster Response Taskforce (Feb 25) • 感染連鎖が突然⾒えた段階ですでに感染源のわからない感染連鎖が国内の各地で進⾏していた • 軽症・無症候を含めPCR検査で感染連鎖の全体像をつかむことはほぼ不可能
How to identify clusters early
When a few isolated cases are found in a
Say this is a cluster region, in most cases, the clusters are not
yet known
Symptomatic
Asymptomatic
Look for clusters based on assumptions that Identify all infected individuals in a cluster,
there is always a cluster around multiple and ask to stay at home for even those
isolated cases without symptoms
Figure 6. How to identify a cluster
Overview 年 3 ⽉ 10 ⽇暫定版）
of cluster response (as of March 10, 2020)
クラスター対応戦略の概要（2020Basis of response in western countries
Detectable cases People who had had contact
Severe cases
Broad PCR
Mild cases testing
Asymptomatic cases
Chain of transmissions
that go unnoticed
Undetected infected personsGuidance on going to the doctor
When to seek help regarding COVID-19
1. What you should keep in mind before you seek help
Consultation Office for
o If you have cold symptoms, such as a fever, do not go to work or school returnees/people who had
and refrain from going out contact
o If you have cold symptoms, such as a fever, record your temperature
2. When you should reach out to Consultation Office for returnees/people who had contact
o If you meet any of the following, please contact immediately
• If you have had a fever of 37.5℃ for over 4 days (including those who
need to keep taking antipyretic)
• Those who are experiencing sluggishness or difficulty breathing
o The following are at higher risk of developing severe symptoms. If the
symptoms persist for more than 2 days, please reach out to Consultation
Office for returnees/people who had contact
• Elderly
• People with underlying conditions such as diabetes, heart failure,
政府広報オンライン
Government PR Online
respiratory diseases (COPD, etc.) or are receiving dialysis 新型インフルエンザの発⽣に備えて
Preparing for new influenza
• Taking immunosuppressants or chemotherapy, etc.
Ministry of Health, Labour,厚⽣労働省2⽉17⽇
and Welfare, February 173 pillars of Japanese response measures • Early identification and early response to clusters • Early treatment, prioritizing intensive care for severe patients, and securing healthcare systems • Behavior change among citizens
Significance of identifying clusters • Can prevent the occurrence of chain of clusters, where new clusters form around an existing cluster • Can identify characteristics that are common across clusters and can effectively call for behavior change to prevent occurrence of clusters • Can estimate transmission status based on identifying isolated cases that are not linked to known clusters
Prevent chains of clusters or occurrence of new clusters
Identify characteristics that are common across
clusters
What we already knew from early analysis Clusters have higher
risk of occurring in
• 3C conditions (closed space, crowded Closed space that is places where the 3
poorly ventilated conditions occur
simultaneously
space, close contact)
Speaking or There are
conversing in many people
close within arms
proximity reachIdentify characteristics that are common across
clusters
What we knew from additional analysis
• Activities that increase breathing
• Using loud voice
• Singing
• Close contact of 1 to multiple people
• Many were not normal droplet infection through cough or sneeze
• Fomite transmission is possibleSignificance of isolated cases that are not linked to a cluster Cluster Isolated case Undetected source
How to be informed of regional transmission
status in real time
• Monitoring of cases, clusters, and isolated
cases
• Monitoring of effective reproductive number,
monitoring based on mathematical modeling
based on estimate of number of patients, etc.
(group led by Hokkaido University)Status of Hokkaido on February 27
Distribution of confirmed cases in Hokkaido on
February 27
• By February 27, there had
been many isolated cases
being reported in Hokkaido
• High likelihood that chains of
clusters or a mega cluster
had gone undetected
• Provided recommendation to
governor of Hokkaido, he
made a decision to declare
state of emergency on
February 28Purpose of Japan’s COVID-19 response
Severe cases (ages 15-64)
Severe cases (over 65)
Number of severe patients (#/100,000)
Minimize impact on social and
economic functions while
maximizing effectiveness of
preventive measures to suppress
transmission
Based on this, biggest goal
was to suppress the speed of
transmissions and reduce the
number of severe cases and Time (days)
Red line shows number of available ventilators per 100,000 persons in Japan.
deaths as
February 24, 2020much as possible
COVID-19 Response Expert Taskforce
COVID-19 Response Expert Taskforce
“COVID-19 status analysis and recommendations” (March 19, 2020)Epi curve in Japan
Date of onset
Only cases with known dates of onsetEffective reproduction number in Japan
Severe cases (ages 15-64)
[Figure 4. Trend in number of confirmed patients who will require ventilators in Japan (left), trend in number of patients on ECMO in Japan (right)]
Number of patients who will require ventilators
Number of patients on ECMO
3/18
3/25
4/15
4/22
4/29
5/13
3/18
3/25
4/15
4/22
4/29
5/13
4/1
4/8
5/6
4/1
4/8
5/6
*Aggregated by Japanese Society of Intensive Care Medicine Japan COVID-19 Response ECMOnetRisk assessment visualization trial by prefecture, 5/25 version
Current status of transmission
o Cumulative cases o Cases per 100,000
Calculated based on confirmed cases by May 23, 2020 by prefecture
新潟⼤学菖蒲川教授作図
Created by Dr. Shobugawa of Niigata UniversityWhat will happen next
Tomas PueyoNumber of total deaths and deaths per 100,000 by country
WHO Trend in number of cases by region
WHO Situation Report
2020, 5.25.How should build society going forward?
• Pre-COVID-19 society
ØSociety had become very susceptible to not only infectious diseases but also various
other threats as a result of globalization and concentration in Tokyo
ØInfectious diseases, economic crisis, poverty, environmental issues, food security, etc.
• With-COVID-19 society
ØIt is highly unlikely that SARS-CoV2 will be eradicated in the short term globally or in
Japan
ØFor a while, society will have to coexist with COVID-19
ØAchieving the Western style “exterminate COVID-19” goal is impossible for the time
being
• Post-COVID-19 society
ØThreat of infectious diseases will continue (new influenza, etc.)
ØPeople will be living under catastrophic levels of threat is we revert back to the
susceptible society of pre-COVID-19
ØWhat will be important is knowing how to build a safe and resilient societyPost-COVID-19 society • Western logic that has led the world up to this point will no longer work • Nationalism that is accelerating in the recent years also won’t work • We live in a world where the global health framework handled by guidelines that require western centric norms have collapsed • Are we OK with creating a world where only totalitarian nations survive? • There is a role for Japan to play, a country that only “requested to refrain” from activities rather than forced measures and have gotten through the pandemic up to this point
Contributions from Tohoku University on
Japan’s COVID-19 response up to this point
• School of Medicine Virology and their alumni (epidemiological analysis)
• School of Dentistry, Professor Ken Kosaka (various areas)
• University Hospital and School of Medicine’s various areas
• HQ
• School of Environmental Studies, Professor Tomoki Nakatani’s team (location
data analysis)
• School of Medicine, Professor Hiroaki Tomita (mental health)
• International Research Institute of Disaster Science, Associate Professor
Yasuto Kunii (mental health)
• Various professors at School of Arts and Letters, School of Law, etc.Possibility for interdisciplinary/international research
• How come Japan has had fewer
cases and deaths thus far?
―Healthcare system
ーMathematical modeling
ーBalance vs social/economical impact
ーAcceptance of behavior change
ーReligious views
ーViews of death/life
Etc.‥‥
• International collaboration in At first, Chicken Pox was thought to be contracted when
“God of Chicken Pox” was haunting you. This was
research with countries and regions accepted as an “unavoidable guest”. People accepted it
in Asia with respect, and worked hard to host it so that it
ーNot divide, connect would leave. The color of red had significant meaning
as part of that hospitality.
Japan Toy Museum感染症共⽣システムデザインチーム
Design Team for System to Coexist with Infectious Diseases
⽇本のモデル検証
Verifying Japan model
Behavioral行動経済学・行動心理学
economics/Behavioral psychology 文化・歴史・哲学・宗教
Culture/history/philosophy/religion
行動経済学などの知見を生か
Behavior change and economic revitalization leveraging 災害や感染症についてのこれまでの文
Cultural/historical/religious/philosophical perspectives
した行動変容と経済活性化.
knowledge around behavioral economics, etc. 化・歴史・宗教・哲学的視点
on past disasters and infectious diseases
Life science (gene analysis)
生命科学（遺伝子解析）
Public health/healthcare
公衆衛生・医療体制 system
Understanding origin of pathogens, analysis of
病原体の起源・国際協調遺伝子解析
genome via international cooperation
最新の公衆衛生対策
Latest public health
measures,
スマートホスピタル. Multidimensional mathematical
Smart hospitals 多次元数理モデル・modeling/AI AI
新たな社会的パラメータを入
Build predictive modeling with new
れた予測モデルの構築societal parameters
Infectious diseases/virology
感染症・微生物学
Measurement science (structural
Research vector animals, diagnostic
感染動態研究、検査関連研究.
tests analysis) GIS GIS
計測科学（構造解析）
地理情報による感染の広がりなどの予
Prediction on transmissions based on
測 location data, etc.
Big data/archive
ビッグデータ・アーカイブ
Quickly build international big data
迅速な国際的ビッグデータの構
and proactive use of archive
築及びアーカイブの積極的活用You can also read
