【学び方】
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だいていますので、ぜひ英文に挑戦してください。
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Coronavirus Disease 2019 (COVID-19)

1.Collect information about current situation (Feature of virus, Domestically andGlobally)
The coronavirus disease 2019 (COVID-19) is an infectious diseases caused by severe
acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It was initially identified in
Wuhan city, Hubei province, China on December 1, 2019. The World HealthOrganization (WHO) declared COVID-19 a Public Health Emergency of International
Concern (PHEIC) on January 30, 2020. Subsequently, COVID-19 was declared apandemic by the WHO on March 11, 2020 based on its worldwide spread and its
seriousness.
COVID-19 is mostly transmitted through droplets or contact with contaminatedobjects. Droplets containing the virus become airborne through the coughing, sneezing,or conversation of infected persons. These virus-containing droplets then disperse,
possibly exposing noninfected individuals. If these noninfected individuals are exposed
to a sufficient number of the contaminated droplets, they might become infected.
Additionally, contact infection, another source of infection, consists of direct contact
such as hand shake and indirect contact through objects such as door knobs or handrails.
The incubation period varies from 1 to 14 days, with 6 days being the most commonly
reported. Subsequently, patients display common cold symptoms such as fever,respiratory symptoms, and general malaise. Symptoms generally continue for about 1
week. In some infected individuals who difficulty in breathing, X-ray or CT areindicated chest pneumonia. Most infected individuals have mild symptoms; however,elderly persons and those with underlying diseases are more likely to have serious
consequences. As a result, careful monitoring is necessary.
https://www.niid.go.jp/niid/ja/diseases/ka/corona-virus/2019-ncov/2487-idsc/idwrtopic/9567-idwrc-2014.html
SARS-CoV-2 is a type of coronavirus that can infect humans. In total, there are seven
known types of coronaviruses that can infect humans, including those which cause
severe acute respiratory syndrome and Middle East respiratory syndrome. However,
the other four types of coronaviruses cause mild common cold. The virus is an singlestranded RNA virus. It has a double film made up of lipids, called “an envelope.” Thevirus cannot proliferate itself. It can replicate when it invades cells such as mucous.
However, it cannot invade the skin; it simply attaches to the skin surface.
If it is attached to the surface of an object, it gradually loses its activity. It has somelevel of activity for 24 to 72 hours on the surface of some types of objects.
https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/dengue_fever_qa_0000
1.html#Q2-1
Importance of collecting information about the current situation
To avoid dissemination of fake news through a social network system, we have collected
information about the current COVID-19 status. When one states an opinion andconsiders a counter measure against COVID-19, one must use information from acredible source.
Domestic situation
Currently, the Japanese Ministry of Labour, Health and Welfare releases data on thenumber of patients reported from each prefecture(https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/0000164708_00001.html#kokunaihassei). The format of release is subject to change. For the table in HP (1) is tested
positive, (2) is divided by whether there are symptoms or not.
It should be noted that patients include those with asymptomatic cases and positive
test cases. The latter refers to patients who test-positive. It is not reported but it if theyshow symptoms.
About Epidemiology
Epidemiology is a branch of science as to examine the spread of disease by quantifyingfrequencies, distributions, and factors affecting the spread of disease among a group ofhumans.
First, patients are classified according to the severity of symptoms. Classifications ofpatients include the following: those who do not display any symptoms (asymptomaticcases), mild cases, severe cases, and mortal cases. In the case of COVID-19, mild cases
displayed symptoms similar to a common cold. Severe cases showed pneumonia anddifficulty breathing.
The pertinent information regarding the outbreak included: the epidemic curve,
incidence, prevalence, mortality rate, and case-fatality rate.
The epidemic curve indicates the number of newly diagnosed patients by their onset
date. Sometimes, the onset date of some patients was unreported. However, we canestimate their onset date from the distribution of onset to among patients with known
onset dates. Similarly, some patients had a delay in reporting the onset date. Even inthis case, we can adjust such a delay from the distribution of duration from onset toreport.
We must note that media generally indicates the number of newly diagnosed patientsby the reported date. This is not an epidemic curve and the difference is sometimes
misleading.
An epidemic curve indicates the number of newly diagnosed patients by their onset
date. However, the onset date is often not reported.
What is the epidemic curve in Shimane Prefecture? The following describes its
development.
Incidence is the number of patients at one day per population. Prevalence was definedas the rate of change of the total number of patients per day, per population.
Mortality rate is defined as the rate of the total number of deaths due to diseases per
population. Case-fatality rate is defined as the rate of the total number of deaths due todiseases per patient. Case-fatality rate may be an important index of the severity of thedisease.
The Symptoms include the following: fever (79%), cough (76%), pneumonia (63%),general malaise (47%), pain in the throat (29%), nasal (25% ), headache (24%), diarrhea(19%), joint or muscle pain (14%), vomiting (6%), acute respiratory distress syndrome(ARDS) (4%), and conjunctival injection (2％).
Taste or olfactory abnormalities have occasionally been reported.
What is the age distribution? You can access information regarding age distribution athttps://www.niid.go.jp/niid/ja/covid-19/9533-covid19-14-200323.html
Why is the prevalence of the disease in children, especially younger than ten years old,very low?
Current situation in the world
The WHO has published “Coronavirus disease (COVID-2019) situation reports.”“Coronavirus disease 2019 (COVID-19) Situation Report – 94(Data as received by
WHO from national authorities by 10:00 CEST, 23 April 2020)”
https://www.who.int/emergencies/diseases/novel-coronavirus-2019/situation-reports/
reported as

April 23

Number of the confirmed

Mortality

patients with COVID-19
New case

73,657

6,689

Total

2,544,792

175,694

Number of the confirmed

Mortality

Update the above table.
Month/Day

patients with COVID-19
New case
Total

Counter measures by government and individuals
Movement before the emergence state declaration

February 25, Head office for counter measures against COVID-19 spread initialed.
February 26, Cancellation voluntarily events
February 27, Schools closed
February 28, State of emergency declared in Hokkaido
March 24, Postponement of Olympic and Paralympic games until 2021
In March 25, The Governor of Tokyo initialed a significant phase to explosively expand
outbreak restrictions; the Ministry of Foreign Affairs recommends to cancel voluntary
travel abroad.
March 26, The Governor of Tokyo recommended strict, but voluntary, quarantine
March 27, The Governor of Tokyo recommend not leaving home on weekends and atnighttime
April 7. The Prime Minister of Japan declared a state of emergency based on a special
law for the influenza pandemic; other cites followed with states of emergencies varying
from April 8 to May 6 in Saitama. Chiba, Tokyo, Kanagawa, Osaka, Hyogo, andFukuoka prefectures.
April 16, The Prime Minister of Japan expanded the state of emergency to the entire
country2.

How will the outbreak cease?

How do you predict the outbreak hereafter?

Transmission of some infectious diseases, especially human-to-human infectious
diseases such as influenza and measles, has been explained by relatively simple partial
differential equation systems. One such system is the well-known SusceptibleInfection-Recovery (SIR) model.
If the pathogen were newly emerging and none in the human population had immunity
at all, all persons would susceptible. When this pathogen invades this community, theinitial patient causes an outbreak.
The key parameter for the SIR model is the reproduction number, R. R represents how
many persons on average can be infected from the initial case until the initial caserecovers. In particular, R in the case of all persons was susceptible is defined as thebasic reproduction number R₀.If R₀ was smaller than one, the initial case could be lessthan one person on average and the outbreak would persist for a long time. Therefore,
R₀ for COVID-19 is definitely greater than one.

A person in a susceptible state can enter the infected state. Some of the infectedpatients showed symptoms, while others were asymptomatic. Some of the symptomaticcases may be severe, and some severe patients may die. Except for mortality cases, theinfected persons will move to the recovery state. They are immune to this pathogen andwill never be infected from the same pathogen, in principal.
If R₀ is higher than one, the initial case infects R₀ persons, then these infectedindividuals infect other R₀ individuals on average. Therefore, the outbreak expands
exponentially. In this situation, does one consider that all persons will be infected for along time? The answer is no. When the outbreak developed, the population ofsusceptible individuals decreased, and conversely, the population of recovery grew.
Thus, among the people surrounding the infected, the proportion of susceptible persons
decreases. The infected individuals cannot infect R₀ persons. For example, half of thesurrounding persons were not susceptible, and the infected individuals can infect only
R₀ /2 persons. In this sense, R decreases when the outbreak is developing. When R isless than 1, the outbreak will cease.
What is the R₀ of COVID-19? During the earlier phase of the outbreak in Wuhan andJapan it was estimated to be greater than two. This means that at the peak of thisoutbreak, half of the population would be infected. When is peak? The interval from aperson being infected to infecting another person was almost 7 days on average.
Moreover, the onset date of the initial case in the community outbreak in Japan was
estimated to be January 14. Then, one can calculate the course of this outbreak.
Does the model represent an outbreak in Japan or the Shimane prefecture? If not, why
does it not? What factor should one take into the model to mimic the outbreak inJapan? This would be key to understand COVID-19 and counter measures against it.

3. Never repeat the history of discrimination.
The history of human and infectious diseases repeatedly shows discrimination ofpeople affected and their families. Leprosy (Hansen's disease) and AIDS are typicalexamples. Whenever these diseases cause anxiety, people are driven by prejudice andhave discriminated people affected in an avoidance manner. Those who became thesubject of discrimination mentally suffered. Infectious diseases not only hurt usphysically but also trigger psychological damage. In fighting infectious diseases, we
also need to fight against the invisible fear.
Have you ever received any insulting comments, or have any of your family beentreated badly when you contracted the influenza ? In 2009 at the beginning of theepidemic of a novel type of influenza (currently known as Type-A Influenza H1N1,
emerged, some discrimination were reported. An unaffected student, who went to aschool where another student was infected, refused to ride a taxi because of the fear of
infection. The students of the same school also met several forms of discrimination,such as dry cleaners refusing to clean their school uniforms.
When we are anxious, we tend to become discriminatory or act on prejudice. The same
applies when a new infectious disease breaks out. On the other hand, no discriminationor prejudice arises against existing infections.
A term, “corona bullying,” already exists. Families of coronavirus patients meet various
harassments. There was also a case of a child being taunted as “corona.” Why does sucha thing happen? It is like treating those affected by the virus as criminals. We need tounderstand that the people affected by the virus are innocent. We need to respect the
dignity of patients as well as their family and medical staff who look after the patients.
We have to protect them from discrimination. It is our responsibility to eliminate
discrimination and prejudice.
Some infections are treatable with vaccines, while there are no vaccines for otherinfections. It is difficult to prevent ourselves from contracting infections without thehelp of vaccines. Because COVID-19 is a new infection, there has been no effective
vaccine or established therapy. Unless we affected it, there is no way to obtain
immunity. Currently, it is known that many infected people have no symptoms, whileothers suffer from severe symptoms and eventually succumb to the disease. Wheneveryone is caught up in the fear of an unknown infection, what we should do is tocorrectly understand official information, dismiss groundless rumors, and stay awayfrom discrimination and prejudice.
Finally, let us remain respectful and thankful for healthcare workers who always
devote themselves to the health of the patients.

【学び方】
その 1： 同じ文章が タイプ A：英文のみ、 タイプ B：英文、日本文併記、タイプ C：日本文で執筆されています。地球全体の問題でありますので、英文でも取り組めるよう工夫していた
だいていますので、ぜひ英文に挑戦してください。
その 2： 本文中の URL をクリックして、公式 HP にアクセスし、公式情報を得てください。
その 3： 読後に https://pro.form-mailer.jp/fms/97aaca99194854 にアクセスして是非、回答してください。
その 4 連休中でもありますので、ご家族にもご一読いただいてください。ご家族の方にもアンケー
トにご回答いただけると幸いです。