新型コロナウィルスを巡っては一次関数と二次関数の区別がつかないことが暴露されてしまった論客（笑）も出現してしまったようなのだが*1。
「コロナウイルス感染症による人口あたりの死亡者数、日本は欧米諸国より目立って少ないが、アジア諸国中では非常に高い／致死率が5.20%に微増（2020/5/27）」https://kojitaken.hatenablog.com/entry/2020/05/28/081709
「北九州市などでの集団感染で懸念される新型コロナウイルス感染症の「ぶり返し」／日本国内の致死率が5.26%に上昇（2020/5/28）」https://kojitaken.hatenablog.com/entry/2020/05/29/060000
「致死率を「真の感染者数」の指標にすることは専門家たちの間でもなされている周知の事項／日本国内での新型コロナウイルス感染症の致死率はほぼ横バイの5.28%（2020/5/29）」https://kojitaken.hatenablog.com/entry/2020/05/30/081334
「死亡率」と「致死率」の違い。ぶっちゃけ、私も「にっしー」なる人物を嗤えないという気がした。公にしたわけではないけれど、私は「致死率」の意味で「死亡率」という言葉を使っていたのだった。
Rebecca A. Harrington “Case fatality rate” https://www.britannica.com/science/case-fatality-rate
“Case fatality rate” https://en.wikipedia.org/wiki/Case_fatality_rate
“Mortality rate” https://en.wikipedia.org/wiki/Mortality_rate
Wikipediaから引用しておく；
In epidemiology, a case fatality rate (CFR) — sometimes called case fatality risk or case-fatality ratio — is the proportion of deaths from a certain disease compared to the total number of people diagnosed with the disease for a certain period of time. A CFR is conventionally expressed as a percentage and represents a measure of disease severity. CFRs are most often used for diseases with discrete, limited time courses, such as outbreaks of acute infections. A CFR can only be considered final when all the cases have been resolved (either died or recovered). The preliminary CFR, for example, during the course of an outbreak with a high daily increase and long resolution time would be substantially higher than the final CFR.
CFRは症例数（case）と死亡数（fatality）との比較。
Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of deaths per 1,000 individuals per year; thus, a mortality rate of 9.5 (out of 1,000) in a population of 1,000 would mean 9.5 deaths per year in that entire population, or 0.95% out of the total. It is distinct from "morbidity", which is either the prevalence or incidence of a disease, and also from the incidence rate (the number of newly appearing cases of the disease per unit of time).[verification needed]
まあ明瞭なんだけれど、以下の記事における”mortality rate”の使い方はちょっとずれているような気がする；
“Coronavirus (COVID-19) Mortality Rate” https://www.worldometers.info/coronavirus/coronavirus-death-rate/
