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Comment by empath75 | Hacker News Reader

I don’t think Korea has a less lethal strain, they’re just testing a lot of people and capturing more mild cases.

Also, thanks to the stupid cult church being the hotbed of infection, the population graph of patients is skewed toward young people: ~30% of all known patients in South Korea are in their 20s, which would lower average mortality rate.

What does stupid cult church mean here?

A large majority of the cases in South Korea are linked to Shincheonji, an organization that calls itself a Christian church but believes the Bible is a secret message to its founder.

I find this to be highly compelling. The “fatality rate” is the number of deaths divided by the number of known cases.

There are several very significant variables which determine the number of known cases, but the upper bound is the number of people tested.

Take for example in WA where the number of cases is ~40 and 10 deaths. The total number of tests last week was some number of hundreds.

With a virus which can be extremely mild in the vast majority of cases and where a test costs thousands of dollars, it is reasonable to expect the total number of cases could be vastly understated.

The WHO has been reporting ~1% of cases are asymptomatic, this has it's own caveats because it comes after China's lock down but there's little reason to believe there a huge numbers of unknown cases out there, at least in countries testing well.

> With a virus which can be extremely mild in the vast majority of cases

I haven't seen a breakdown of how many get what the "mild" symptoms, but anything not requiring hospitalization including pneumonia are considered mild. Many of these mild cases would at least be going to their doctor to get a week off work.

Edit - found a break down: https://www.who.int/docs/default-source/coronaviruse/who-chi...

> As of 20 February 2020 and 12based on 55924 laboratory confirmed cases, typical signs and symptomsinclude:fever (87.9%), dry cough (67.7%), fatigue (38.1%), sputum production (33.4%), shortness of breath (18.6%), sore throat (13.9%), headache (13.6%), myalgiaor arthralgia (14.8%), chills(11.4%), nausea or vomiting (5.0%), nasal congestion (4.8%), diarrhea (3.7%), and hemoptysis (0.9%), and conjunctival congestiion (0.8%).

Those symptoms are worthy of a doctor visit and skipping work.

> The WHO has been reporting ~1% of cases are asymptomatic, this has it's own caveats because it comes after China's lock down but there's little reason to believe there a huge numbers of unknown cases out there, at least in countries testing well.

Unfortunately, the United States is currently a country that is not testing well.

Knowing 1% of reported cases are asymptomatic doesn’t tell us anything about what percent of asymptomatic cases are unreported. Only way to know what is testing with random sampling from the asymptomatic general population.

> Only way to know what is testing with random sampling from the asymptomatic general population.

They did. They tested a lot of people in contact with infected people (so even more likely to be an asymptomatic carrier than the general population) and their findings from the link above is:

> Asymptomatic infection has been reported, but the majority of the relatively rare cases who are asymptomatic on the date of identification/report went on to develop disease. The proportion of truly asymptomatic infections is unclear but appears to be relatively rare and does not appear to be a major driver of transmission.

Given the evidence the onus is proof is now on anyone claiming there are large amounts (of course there will always be some) of undetected cases.

I am not talking about entirely asymptomatic cases, which I believe are fairly rare. I am talking about mild cases which could be easily mistaken for a common cold, which is the most common presentation.

I think what you may be missing is that 100,000 people in WA could have gone to their doctor last week with “a cold” and they wouldn’t have been tested for COVID, because the FDA would not allow state labs to run the tests and the CDC refused to run it on mild cases.

I use the example of WA because it’s glaringly obvious that a lack of testing has resulted in a significant number of cases going undetected over the last couple weeks in that area.

The old CDC guidelines only allowed severe cases to be tested, so the only confirmed COVID cases were severe. Resulting in a “fatality rate” that was pushing 10%.

So it’s just an example of how this number is inflated by lack of testing. I believe a similar situation is playing out in Italy.

By comparison, South Korea has an extremely robust testing regime (free drive through testing stations, over 100,000 tested, capacity of over 10,000 per day) [1] and has identified 6,284 cases and has seen 40 deaths with currently 52 in serious condition. That puts their “known case fatality rate” at 0.6%-1.5%.

Simply put, the “known case fatality rate” can only possibly overstate the actual fatality rate, unless you believe there are deaths due to COVID happening that are being misattributed. This is obviously an entirely different category of error than not testing someone with a mild cold.

It’s useful to take what we know about “known case fatality rate” in heavily-tested populations and we can use this to estimate how many undetected cases are present in the population in under-testing locales. E.g. 10 COVID deaths would point to the likelihood of over 1,000 actual cases of COVID in the community. This of course assumes similar demographics and standards of care, which may not be the case.

[1] - https://www.ctvnews.ca/health/south-korea-takes-fast-food-ap...

~90% of cases get a fever which is uncommon for a cold so if there were large amounts of people with the disease it would at least be showing as a huge spike of people with the flu, plus we'd likely see a spike in deaths. It won't be mistaken for just a cold. The way it's playing out in Italy is that there were a lot of diagnosed cases early on but once the testing caught up they seem to be on the same exponential curve as everywhere else, but this was only high in percentage terms and low in raw numbers.

There is definitely under reporting of cases (and some misdiagnosed deaths), but so far no reason to think it's a tip of an iceberg type of scenario and there are large masses of undiagnosed people. For calculating mortaility rates there's also the lag time between getting the virus and death to take into consideration.

Going back to your original post about the fatality rate in WA, the numbers are simply too low to indicate anything at all. There are only 4 countries on Earth we can get much statistical significance from and of those Iran is the only one that lacks testing at the moment.

You make a very good point that a high fever is uncommon with a cold, and so at that point people would be thinking they perhaps have the flu and, depending on the culture and health care system, could decide to go get a flu test.

Once that’s negative you would expect maybe a COVID test would be done, again, depending on the health care system, availability of testing, and perhaps the financial impact.

>where a test costs thousands of dollars

Is this true?

I imagine US insurance companies could make this true if it's not

If the average time of infection to death is 18 days and the doubling time is 5 days, 10 deaths today would indicate at a 2% mortality rate:

500 infections 18 days ago.

~6800 infections today in the community.

This is an interesting simulation, but keep in mind you are extrapolating both backwards by 50x and then, from there, also forwards with an aggressive exponential multiplier, all starting with a very low n.

So there are an enormous number of variables which can cause reality to diverge. Each on of those 10 deaths have a unique situation which lead to that point.

For example, if they are all related to the same cluster (and I believe they are), and that cluster is an elderly demographic which doesn’t get outside much, then the R0 will be significantly lower than 10 totally unrelated business people traveling for work, or who might feel pressure to go into their offices despite feeling a bit feverish... totally different profiles and potential impact.

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