I'm not convinced since maybe in the early days only the worst cases were being tested so they may be missing a significant proportion of the population. The article itself didn't balance the strengths or weaknesses of their approach which would be helpful. Open to being told otherwise.
From the article: "We re-estimated mortality rates by dividing the number of deaths on a given day by the number of patients with confirmed COVID-19 infection 14 days before."
From this I understand that if a patient was infected but was not tested and confirmed until a later date, they would not be included in the denominator. Hence the denominator may be artificially low and thereby inflating the mortality rate.
15.2% omg ...
I have so many questions without clear answers...
Do asthmatics have a higher case-fatality rate?
Is it true that when we catch the coronavirus, it leaves serious after-effects on our health?
> We re-estimated mortality rates by dividing the number of deaths on a given day by the number of patients with confirmed COVID-19 infection 14 days before.
This seems seriously flawed to the point of being outright stupid and irresponsible to spread in my opinion.
They basically assume the number of confirmed infections 14 days ago better represents the real number of infections on that date than the number of confirmed infections today. That does not seem right.
1. Infected persons test positive for the virus only after it breaks out, so the number of confirmed cases is always lagging behind the real number of infections.
2. As they mention in the article, but choose to ignore, a large number of infected people are asymptomatic or show only mild symptoms and will usually not be tested. The UK government yesterday assumed the real number of infections to be 10-20x higher than the number of confirmed cases. [1]
So taking the - IMHO still valid - approximation of 2-3% mortality rate for confirmed COVID-19 cases and considering the assumption of an infection rate 10-20x higher than the number of confirmed cases, the real mortality rate should be in the ballpark of 0.2%.
> They basically assume the number of confirmed infections 14 days ago better represents the real number of infections on that date than the number of confirmed infections today.
No, they assume it better represents the real number of infections present long enough that someone would have died of them if they were going to. Which may also be a problematic assumption, but is a very different assumption from what you describe.
“ a large number of infected people are asymptomatic or show only mild symptoms and will usually not be tested”
No.
WHO, China, Italy and South Korea have all looked and the hypothesised majority of asymptomatic cases doesn’t exist.
China did 320k background tests in one province and had a 0.5% positive rate. There’s some asymptomatic cases, but no evidence suggests there are massive numbers.
These 320k tests were performed in the Guangdong province which has a population of 113 million and ~10,000 confirmed COVID-19 cases, or about 0.009% of the population.
If they found a 0.5% positive rate on background tests there, that would suggest the real number of cases to be hundreds of thousands in that province alone.
That article suggests that the 320,000 tests were not a background test, but they tested "worried people [who] flooded fever clinics to be tested". Actual numbers across all population would hopefully be much less than 0.5%.
The article also states "The claim [that there's not huge transmission beyond what you can see clinically] was quickly challenged by an infectious diseases expert who serves on a committee that advises the WHO's health emergencies program.".
It is stupid. Instantaneous CFR is rarely knowable because of the problems of separating the infection data into groups of those who were infected simultaneously and tracking their ultimate resolution.
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[ 2.5 ms ] story [ 37.1 ms ] threadWHO looked at 320k background tests and less than 0.5% were positive.
From this I understand that if a patient was infected but was not tested and confirmed until a later date, they would not be included in the denominator. Hence the denominator may be artificially low and thereby inflating the mortality rate.
This seems seriously flawed to the point of being outright stupid and irresponsible to spread in my opinion.
They basically assume the number of confirmed infections 14 days ago better represents the real number of infections on that date than the number of confirmed infections today. That does not seem right.
1. Infected persons test positive for the virus only after it breaks out, so the number of confirmed cases is always lagging behind the real number of infections.
2. As they mention in the article, but choose to ignore, a large number of infected people are asymptomatic or show only mild symptoms and will usually not be tested. The UK government yesterday assumed the real number of infections to be 10-20x higher than the number of confirmed cases. [1]
So taking the - IMHO still valid - approximation of 2-3% mortality rate for confirmed COVID-19 cases and considering the assumption of an infection rate 10-20x higher than the number of confirmed cases, the real mortality rate should be in the ballpark of 0.2%.
[1] https://www.telegraph.co.uk/global-health/science-and-diseas...
No, they assume it better represents the real number of infections present long enough that someone would have died of them if they were going to. Which may also be a problematic assumption, but is a very different assumption from what you describe.
No.
WHO, China, Italy and South Korea have all looked and the hypothesised majority of asymptomatic cases doesn’t exist.
China did 320k background tests in one province and had a 0.5% positive rate. There’s some asymptomatic cases, but no evidence suggests there are massive numbers.
If they found a 0.5% positive rate on background tests there, that would suggest the real number of cases to be hundreds of thousands in that province alone.
You seem to be referring to this report: https://www.statnews.com/2020/02/25/new-data-from-china-butt...
That article suggests that the 320,000 tests were not a background test, but they tested "worried people [who] flooded fever clinics to be tested". Actual numbers across all population would hopefully be much less than 0.5%.
The article also states "The claim [that there's not huge transmission beyond what you can see clinically] was quickly challenged by an infectious diseases expert who serves on a committee that advises the WHO's health emergencies program.".
Higher CFR depends largely on male gender, older age, and/or pre-existing conditions, with some random healthy people who also succumb to it.