12 ms·

The general issue with this measure of mortality (dead/(infected + dead)) is that you're assuming that the infected won't die. In a disease that is exponentiall

by nik_s 7y ago

The general issue with this measure of mortality (dead/(infected + dead)) is that you're assuming that the infected won't die. In a disease that is exponentially growing, a better approximation of evaluating your survival chances is to look at the death to recovery rate (dead / (recovered + dead)). Based on the available data [1], we are closer to 7.8% than 2% mortality, which is closer to the final mortality rate of SARS of 9.6% [2]. Nevertheless, I think all these statistics need to be taken with a grain of salt - I doubt that the numbers we are seeing are of very high quality, given the political and cultural pressures in China to underreport, the lack of test kits, corona virus deaths being attributed to other diseases, ... On the flip side, it's very likely that mild cases will never be reported, which in turn would decrease the mortality rate. [1] https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6 https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.h... [2] https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndr... [edit: corrected the formula - thank you @anhner and @11thEarlOfMar for spotting the mistake] [edit: indicated that there's also a chance of under-reporting mild cases - my edit coincided with @Tenoke's post - sorry for noticing this late @Tenoke]

anhner 7y ago
I don't understand your first argument. Surely increasing the denominator would lower the mortality percent? Also does the total number of infected not include the dead?
- nik_s 7y ago
  Indeed, you are right - I corrected the formulas.
- m3kw9 7y ago
  But the infected who isn’t dead may or may not die at the end. So using infected as the denominator is not accurate. But using just the recovered as denim Arie is also incorrect unless you have enough samples. Using China’s figures are wildly inaccurate because of lack of tests and transparency. So maybe a better complex model can be derived from current datas
- deleted 7y ago
  [deleted]
11thEarlOfMar 7y ago
I think you mean (dead/(recovered+dead)).
- nik_s 7y ago
  Indeed - thank you, I adapted the formula in the original post.
anonsivalley652 7y ago
It's difficult/impossible to put a specific probability (which would be an oxymoron) on any one particular person dying. The somewhat vague risk factors take time to accumulate from statically-larger samples if there were more deaths. We know it's a couple of orders of magnitude worse than the seasonal flu but less than the 1918 flu and the plague, hence the extreme quarantine measures to reduce its infectivity to essentially 0. Once quarantine goes into effect, it doesn't matter how infectious is a pathogen because it's dead because of math.
- CrazyStat 7y ago
  > specific probability (which would be an oxymoron) Not at all. For example, if I flip a fair coin, I can assign a very specific probability to the event that I get heads. > We know it's a couple of orders of magnitude worse than the seasonal flu Maybe one order of magnitude. Seasonal flu is about 0.1-0.2% mortality in the US. The evidence suggests that covid-19 is less than 1% mortality. > hence the extreme quarantine measures to reduce its infectivity to essentially 0 It doesn't need a high mortality rate to justify extreme quarantine measures. The fear is that it will become a perpetual thing, another seasonal illness like the flu. Even if the mortality rate were the same as the flu it would be worth taking extreme measures to avoid that.
Tenoke 7y ago
>The general issue with this measure of mortality (dead/infected) is that you're assuming that the infected won't die. On the other hand, there are also a lot of infected who only have a mild version and are never checked and recorded, which swings it in the other direction. Edit: Seems like the parent post later edited their post to mention the above.
- swader999 7y ago
  In the hardest hit areas like Wuhan, almost everyone has been tested.
  - joosters 7y ago
    Reference for that, please?
    - swader999 7y ago
      In the who presentation, Dr Bruce Aylward mentioned this. I'll try to dig up the exact spot in the clip for you. At 1:07:44 this is discussed in depth: https://youtu.be/-o0q1XMRKYM https://youtu.be/-o0q1XMRKYM
      - joosters 7y ago
        Thanks for the link! He says that there have been door to door testing of temperatures, and I'd nitpick by saying that's not quite the same thing as testing everyone for the virus, but it is better coverage than I had realised.
        swader999 7y ago
        Yeah he's rolling with what he's got. The antibody studies that come at the tail of these things would be definitive.
        JoeAltmaier 7y ago
        Surprised! I worry about unintended consequences. During an epidemic, officials visit every home! Potentially spreading the virus unintentionally thru healthcare personnel. Don't know if I'd open the door to somebody who admits having visited thousands of people before getting to me...
11thEarlOfMar 7y ago
According to Johns Hopkins data Feb 27, 2020 [0], Iran would come to: Deaths: 26 Recovered: 49 (26 / (26 + 49)) = 34.7% [0] https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6 https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.h...
- CrazyStat 7y ago
  We can conclude that Iran is severely underreporting cases.
  - hanspeter 7y ago
    Or severely overreporting deaths.
- gentleman11 7y ago
  We also have that Iran does not have the health care system to even provide proper equipment for their health staff. This is a case of massive under reporting, but unfortunately that means they are not containing it and do not even know the extent of their problem. That is the teal worry with Iran, not some super deadly variant The diamond princess saw almost 100% exposure and only 0.5% of people died who got infected. Depending if you choose that stat, or the 2% WHO star, that suggests 15-100x more cases are in Iran than their lousy health system realizes.
ableal 7y ago
A few days ago I looked up the numbers for the 1918 flu - https://en.wikipedia.org/wiki/Spanish_flu https://en.wikipedia.org/wiki/Spanish_flu - world population: 1800 million - infected: 500 million - dead: 50 million I did not know it had been that bad.
- Loughla 7y ago
  There's this weird social media thirst for this to become the next spanish flu. My family (midwest conservatives) fall into one of two camps: 1. This was sent by Jesus and is a prelude to the rapture, literally. 2. The spanish flu happened 100 years ago, and 100 is a big round number, so this is going to do the same things. It's very strange and surreal around the home town right now. Many elderly are openly embracing what they see as their future deaths because it's God's will. I'm very, very confused by all of this.
  - LarryDarrell 7y ago
    My own personal opinion is that the Great Recession and it's repercussions (inequality, deaths of despair, the hallowing out of middle American economies, the opioid crises, Flint water crises, etc) over last 10+ years have really ramped up a zeitgeist of inevitable doom. I don't really blame anyone in the Midwest for being full of doom and gloom, because for the most part that's all they have known for the last decade. My other opinion is that more so than racism and actually believing Trump would make America great again, that most of the support that pushed Trump over the edge came from wanting to burn the whole thing down.
    - Loughla 7y ago
      I would agree with that. During the last election cycle (and already this one), the one thing the polls consistently got wrong was just how pissed "Joe-Midwest Average Voter" is that his life is much worse than his parents' were at the same age. When people online and in the news express how they just don't understand why people still support Trump, it's because they're not trying to understand. If all you care about is disrupting as much of the system as possible and pissing people off as much as possible, you're getting exactly what you wanted.
contravariant 7y ago
Your formula has the opposite problem, by looking at cases that have a known outcome you are biasing results towards cases that end quickly (in particular cases that end in death). For a proper estimate we should look at cases where the infection is known to have begun e.g. a month ago. Then the mortality rate should be somewhere between dead/infected and dead/(dead + recovered).
- swader999 7y ago
  There's also the possibility of reinfection and false negatives. The best data we have is not even close to perfect.
- nik_s 7y ago
  > Your formula has the opposite problem, by looking at cases that have a known outcome you are biasing results towards cases that end quickly (in particular case that end in death). Unless I'm mistaken, that would only be true if cases that end in death are much faster than the cases that end in recovery. I have found it difficult to find detailed statistics on the topic, so I cannot tell you that it's definitely true or not, but I agree that it's an important variable that should be taken into the equation.
  - twotwotwo 7y ago
    With many viral respiratory bugs, symptoms appear a few days after infection, peak a few days after that, and then there's a long tail of sniffling and coughing. Deaths happening in the peak and recovery being declared nearer the end of the tail leads to the intuition that maybe deaths could cluster earlier than recoveries. Of course, I don't know how/when recoveries are being tallied right now and don't want to guess. Bigger picture: lots of factors go into a good estimate, and epidemiologists are not new to mathematical modeling. When back-of-the-envelope math doesn't get the same prediction as the consensus models of what's going on, we shouldn't assume the epidemiologists are wrong.
mns 7y ago
I do have one question and I'm asking this seriously, not to start an argument or to attack someone. I also saw this here in a lot of the posts about covid-19. We have numbers, but every time people tend to ignore them or say we should not trust the numbers, take them with a grain of salt, "I think this is way worse, it's going to get way worse" and so on. It's like there is this thirst for disaster or some global drama everywhere, and this is not something that I would expect from Hackernews. If the numbers don't align with our hopes or fears, we should take them with a grain of salt and trust the gut feeling of whoever comments. It's quite weird to see that when it comes to this, people seem to think that it's some sort of conspiracy, China is hiding numbers, now EU is not doing things properly, as I see it everywhere "my country can't have 0 cases, I know that our airport is a big hub and it can't be, we will be doomed as we probably have hundred of cases instead of none and our government is not doing anything". I'm not saying that this virus is not a threat and I worry for my parents as this could be a big issue for their condition, but we've gone down the rabbit hole with the hysteria in the press and online and it's scary to see this need for a global pandemic and the urge to constantly feed the panic monster.
- dpau 7y ago
  ever since the beginning of this crisis, countries have been either hiding or underreporting the numbers. lack of adequate testing means that clusters are discovered late, after the virus has had a chance to spread. it's not so much a thirst for disaster as it is a thirst for knowledge so that we can better prepare ourselves. even in the US, the CDC seems at odds with the president as to the severity of the virus and its spread. if anything, it's governments that are "aligning the numbers" so as to avoid mass panic, downturns in markets, etc.
  - logjammin 7y ago
    What evidence can you point to of this "hiding"? Lack of adequate testing is a factor, I Grant you, and a big one -- but clusters are discovered late because it now appears that people can shed virus when they're not symptomatic.
    - 7y ago
wcoenen 7y ago
> a better approximation of evaluating your survival chances is to look at the death to recovery rate (dead / (recovered + dead)) This formula is still fundamentally wrong because it assumes that the time between infection and death is the same as the time between infection and recovery. I don't see why that would be true.
- Retric 7y ago
  The argument is it’s a closer approximation. Abstractly if the average death took place X days after infection and recovery took more than 2X days after infection then deaths:infection is a better metric. On the other hand if the average recovery takes less than 2X then deaths:recoveries is a better metric. And if it’s close to 2X then averaging them is a better idea. Of course detection also lags infection so that’s another consideration. I suspect that’s the real difference as outside of China a lot of cases where discovered before symptoms developed due to blood tests. PS: South Korea has 1,766 confirmed cases, 13 dead, and 26 recovered. Iran has 245 confirmed cases, 26 dead, and 21 recovered. Those numbers are far enough apart to suggest underlying differences in reporting, which is I a larger issue. https://en.wikipedia.org/wiki/2019–20_coronavirus_outbreak https://en.wikipedia.org/wiki/2019–20_coronavirus_outbreak
blattimwind 7y ago
I don't think a sensible mortality rate can be computed at this point, because we have no idea, not even good estimates, how many people contracted the pathogen. 10 dead out of 1000? Or 10000? Or 20000? In Wuhan they apparently checked ~almost everyone for symptoms - temperature - but showing symptoms != infected. So far it seems that there is an exceptionally large proportion of infected people showing no or barely any symptoms.
- admax88q 7y ago
  doesn't that mean that we can only compute an upper bound on the mortality rate? We will never know for certain how many cases there are, but _of the cases we know about_ we can compute a reasonable upper bound on mortality. Were more likely not to learn of cases than were not fatal than we are of cases which are fatal as severe cases are more likely to seek treatment.
  - marcosdumay 7y ago
    With the measurement people are using, yes, you can only know an upper bound. It's possible to discover an actual estimate, but it takes time and resources. Researchers may care about doing that after the crisis passes, but it's very unlikely anybody will care about this right now.
    - admax88q 7y ago
      Which is fine, people keep pointing to all these unknown as "we can't possibly compute the morality rate!" Which leaves the door open for assuming its way higher than estimated, when in reality current estimates are likely an upper bound.
      - marcosdumay 7y ago
        Although I think the official estimates are severely overestimating the lethality (by an order of magnitude), I also think there isn't enough information for establishing an upper bound yet. Current estimates are bad.
CrazyStat 7y ago
> On the flip side, it's very likely that mild cases will never be reported, which in turn would decrease the mortality rate. Indeed. This calculation ignores severe underreporting of mild cases--for example, Johns Hopkins researchers (the same ones who made that map you linked to for data) estimated that only ~10% of cases in mainland China (mostly Wuhan at the time) were being reported [1]. That would put the mortality rate at under 1%, which is close to the evidence we have from elsewhere (e.g. the Diamond Princess). dead / (recovered + dead) is only a reasonable estimate if you actually have good numbers for the recovered count. We don't, so it's irresponsible to use it. [1] https://systems.jhu.edu/research/public-health/ncov-model-2/ https://systems.jhu.edu/research/public-health/ncov-model-2/
- Alex3917 7y ago
  > That would put the mortality rate at under 1%, which is close to the evidence we have from elsewhere (e.g. the Diamond Princess). Since it takes 3+ weeks to die from this illness, we're not going to know the fatality rate from the diamond princess for another month. And that's still going to be a lower bound since they'll all be getting medical care from often before they're even diagnosed.
  - learc83 7y ago
    >And that's still going to be a lower bound since they'll all be getting medical care from often before they're even diagnosed. It's not a lower bound because cruise ships skew much older than the general population. All 4 who have died so far have been in their 80s.
    - Alex3917 7y ago
      Good point. That you can at least try to correct for to match various populations though.
  - nswest23 7y ago
    We know the percentage of people who are in critical condition and it's very low.
cm2187 7y ago
Well the death rates seem to be lower outside of China so that doesn’t seem to support that China is understating the lethality of the virus, nor that it is particularly more lethal than the chinese numbers. Re the higher death rates in the chinese province, I thought it was due to people not showing up to hospital when having milder symptoms, but I watched an interview of a french doctor who suggested it is rather because of the lack of medical infrastructures in that region, to which the chinese remediated by building these spectacular field hospitals.
furyofantares 7y ago
I agree with your general point that rate=deaths/infections is making a big assumption about unresolved cases and almost surely gives a too low number -- but rate=deaths/recovered I think does the same thing in the opposite direction. Unfortunately we just don't know right now. It would be nice to see deaths vs recovered vs mild cases vs critical cases for people who have been infected >N days, but that's much more nuanced information to consume than some "death rate". Btw, you made a point about exponential growth, but is that happening? The logarithmic graph on https://www.worldometers.info/coronavirus/ https://www.worldometers.info/coronavirus/ appears flatlined to me. Maybe (probably?) that's just about containment in China, but when we're discussing death rates that's where most of the data is.
ghostpepper 7y ago
I have heard this argument that the real mortality rate may be under-reported for this reason since the outbreak began around the start of January and it makes sense to me. On the other hand, what do you say to the claims that the real mortality rate is much lower due to people infected but with symptoms so mild they don't seek treatment?
Alex3917 7y ago
Right. It takes 3+ weeks to die from CoVID-19, so if they're looking at people who were diagnosed as late as Feb. 11th then this is going to be a substantial underestimate of fatality. Especially since as awareness of the disease has increased, the time to diagnosis after first symptoms has fallen from 5 - 6 days to 1 - 2 days.
wtvanhest 7y ago
5 people have died that were on the princess cruise out of 705 infected. At just over 1/2 a percent, it is more deadly than the flu, but not 2% and certainly not 7.8% The princess cruise gives us a crucial piece of information which is a fully tested population. 2 things to consider: 1) population is like older due to being a princess cruise which would increase death rate. 2) not everyone is cleared yet, so more deaths could come
- generalpass 7y ago
  And how healthy are their immune systems? I imagine they are eating a lot of sugary foods, drinking more than usual and staying up later in a time zone they are not acclimated for.
- learc83 7y ago
  Only 4 have died, and all 4 were in their 80s.
  - wtvanhest 7y ago
    You are correct: https://bnonews.com/index.php/2020/02/the-latest-coronavirus-cases/ https://bnonews.com/index.php/2020/02/the-latest-coronavirus... I must have remembered the wrong number. 4/705 = 0.5% (1/2 a percent), which is still pretty high vs the flu, but not 2% or 7.8% or whatever crazy numbers people are quoting.
- TheHypnotist 7y ago
  Wouldn't the quick discovery and level of care also factor in?
0x8BADF00D 7y ago
The infected might be terribly maimed for the rest of their life as well. Can you imagine if they develop COPD or some similar chronic inflammatory lung disease because of this?
mrb 7y ago
You are exactly correct. With the formulas you described: naïve CFR = deaths / cases resolved CFR = deaths / (deaths + recoveries) It can be shown pretty dramatically in outbreak simulations how more accurate the resolved CFR is than the naïve CFR. See for example the chart https://blog.zorinaq.com/assets/outbreak2.svg https://blog.zorinaq.com/assets/outbreak2.svg In that specific example, the naïve CFR underestimates by 5x, while the resolved CFR is only off by ~1.3x. I ran this simulation as part of my blog post on how to estimate the Case Fatality Ratio of the coronavirus: https://blog.zorinaq.com/case-fatality-ratio-ncov/ https://blog.zorinaq.com/case-fatality-ratio-ncov/
deleted 7y ago
[deleted]
partiallypro 7y ago
The survival rate is also probably thrown off though because some countries have better trained health professionals. No one in the US (that made it to US care) has died as of yet. In other countries without advanced facilities available, the rates are much higher. If the disease hits Africa and more of the ME, the rate will go up. While in the US, and richer countries like Germany, etc the rate will probably be low.
- WaltPurvis 7y ago
  There's some validity to that, but a lot depends on how widespread the disease becomes. There are about 100,000 ICU beds in the US, and they can't all be allocated to coronavirus patients. Not having access to a ventilator would be pretty much equivalent to a death sentence for some patients. There are <100,000 ventilators in the US, and they're not evenly distributed (some areas and hospitals have very few). It wouldn't take much of a pandemic to exhaust our supply of ICU beds and other critical-care resources.
john_moscow 7y ago
The dead / (recovered + dead) is the worst-case assessment, since most of the people who have not technically recovered yet (but may not even have any symptoms anymore), won't die either. The dead / (infected + dead) is the best-case assessment, since some of the people who have not recovered yet, will die. A somewhat better metric would be dead / (infected X days ago) where X is the median time for the illness to fully develop.
yurlungur 7y ago
To me this article seems to be missing the most important stat from the original article, which is that the case fatality rate as measured is 2.9% inside Hubei (possibly under-reported) and 0.4% outside. I think this strongly suggests that, as one would expect, the situation is much worse if patients lack the medical resources for care. And it also shows how important quarantine and preventative measures are.
ummonk 7y ago
Dead / (dead+recovered) is overestimating (even assuming 100% detection of mild cases) because it takes longer for people to recover than to die from it.
gentleman11 7y ago
You have to take into account that 80% of cases are not severe, so you could have it and just think it was the flu. Most people wouldn’t go to the hospital in that case, so that 7.8% figure is not realistic. The WHO numbers (2%) do at least try to take this into account I’m legitimately confused why we’re seeing these responses make top response on hn. It’s WEIRD
baxtr 7y ago
You assume recovered data is correct? Maybe it takes longer to be counted as recovered than it takes on average to die. This could change the rate
stewbrew 7y ago
How would you know the number of infected people? You know the number of infected people with symptoms that were severe enough to get tested. For the same reason: How would you know the number of people who have recovered? You know the number of people who were observed and then recovered.
divbzero 7y ago
On another page [1] Worldometer correctly explains the better estimate of mortality deaths / (recoveries + deaths) for ongoing outbreaks. Not sure why they got it wrong here. [1]: https://www.worldometers.info/coronavirus/coronavirus-death-rate/ https://www.worldometers.info/coronavirus/coronavirus-death-... "Coronavirus Mortality Rate"
nswest23 7y ago
How on earth is this the top rated comment? You can't make up your own statistical measure for mortality rates for a novel virus unless you're an epidemiologist. Of course there is under-reporting of mild cases...there's a shortage of test kits!
zachwill 7y ago
Built a simple `PyMC3` model based on your comment: https://github.com/zachwill/covid-19 https://github.com/zachwill/covid-19

by nik_s 7y ago

anhner 7y ago

I don't understand your first argument. Surely increasing the denominator would lower the mortality percent? Also does the total number of infected not include the dead?

nik_s 7y ago
Indeed, you are right - I corrected the formulas.
m3kw9 7y ago
But the infected who isn’t dead may or may not die at the end. So using infected as the denominator is not accurate. But using just the recovered as denim Arie is also incorrect unless you have enough samples. Using China’s figures are wildly inaccurate because of lack of tests and transparency. So maybe a better complex model can be derived from current datas
deleted 7y ago
[deleted]

11thEarlOfMar 7y ago

I think you mean (dead/(recovered+dead)).

nik_s 7y ago
Indeed - thank you, I adapted the formula in the original post.

anonsivalley652 7y ago

It's difficult/impossible to put a specific probability (which would be an oxymoron) on any one particular person dying. The somewhat vague risk factors take time to accumulate from statically-larger samples if there were more deaths. We know it's a couple of orders of magnitude worse than the seasonal flu but less than the 1918 flu and the plague, hence the extreme quarantine measures to reduce its infectivity to essentially 0. Once quarantine goes into effect, it doesn't matter how infectious is a pathogen because it's dead because of math.

CrazyStat 7y ago
> specific probability (which would be an oxymoron) Not at all. For example, if I flip a fair coin, I can assign a very specific probability to the event that I get heads. > We know it's a couple of orders of magnitude worse than the seasonal flu Maybe one order of magnitude. Seasonal flu is about 0.1-0.2% mortality in the US. The evidence suggests that covid-19 is less than 1% mortality. > hence the extreme quarantine measures to reduce its infectivity to essentially 0 It doesn't need a high mortality rate to justify extreme quarantine measures. The fear is that it will become a perpetual thing, another seasonal illness like the flu. Even if the mortality rate were the same as the flu it would be worth taking extreme measures to avoid that.

Tenoke 7y ago

>The general issue with this measure of mortality (dead/infected) is that you're assuming that the infected won't die. On the other hand, there are also a lot of infected who only have a mild version and are never checked and recorded, which swings it in the other direction. Edit: Seems like the parent post later edited their post to mention the above.

swader999 7y ago
In the hardest hit areas like Wuhan, almost everyone has been tested.
- joosters 7y ago
  Reference for that, please?
  - swader999 7y ago
    In the who presentation, Dr Bruce Aylward mentioned this. I'll try to dig up the exact spot in the clip for you. At 1:07:44 this is discussed in depth: https://youtu.be/-o0q1XMRKYM https://youtu.be/-o0q1XMRKYM
    - joosters 7y ago
      Thanks for the link! He says that there have been door to door testing of temperatures, and I'd nitpick by saying that's not quite the same thing as testing everyone for the virus, but it is better coverage than I had realised.
      - swader999 7y ago
        Yeah he's rolling with what he's got. The antibody studies that come at the tail of these things would be definitive.
      - JoeAltmaier 7y ago
        Surprised! I worry about unintended consequences. During an epidemic, officials visit every home! Potentially spreading the virus unintentionally thru healthcare personnel. Don't know if I'd open the door to somebody who admits having visited thousands of people before getting to me...

11thEarlOfMar 7y ago

According to Johns Hopkins data Feb 27, 2020 [0], Iran would come to: Deaths: 26 Recovered: 49 (26 / (26 + 49)) = 34.7% [0] https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6 https://gisanddata.maps.arcgis.com/apps/opsdashboard/index.h...

CrazyStat 7y ago
We can conclude that Iran is severely underreporting cases.
- hanspeter 7y ago
  Or severely overreporting deaths.
gentleman11 7y ago
We also have that Iran does not have the health care system to even provide proper equipment for their health staff. This is a case of massive under reporting, but unfortunately that means they are not containing it and do not even know the extent of their problem. That is the teal worry with Iran, not some super deadly variant The diamond princess saw almost 100% exposure and only 0.5% of people died who got infected. Depending if you choose that stat, or the 2% WHO star, that suggests 15-100x more cases are in Iran than their lousy health system realizes.

ableal 7y ago

A few days ago I looked up the numbers for the 1918 flu - https://en.wikipedia.org/wiki/Spanish_flu https://en.wikipedia.org/wiki/Spanish_flu - world population: 1800 million - infected: 500 million - dead: 50 million I did not know it had been that bad.

Loughla 7y ago
There's this weird social media thirst for this to become the next spanish flu. My family (midwest conservatives) fall into one of two camps: 1. This was sent by Jesus and is a prelude to the rapture, literally. 2. The spanish flu happened 100 years ago, and 100 is a big round number, so this is going to do the same things. It's very strange and surreal around the home town right now. Many elderly are openly embracing what they see as their future deaths because it's God's will. I'm very, very confused by all of this.
- LarryDarrell 7y ago
  My own personal opinion is that the Great Recession and it's repercussions (inequality, deaths of despair, the hallowing out of middle American economies, the opioid crises, Flint water crises, etc) over last 10+ years have really ramped up a zeitgeist of inevitable doom. I don't really blame anyone in the Midwest for being full of doom and gloom, because for the most part that's all they have known for the last decade. My other opinion is that more so than racism and actually believing Trump would make America great again, that most of the support that pushed Trump over the edge came from wanting to burn the whole thing down.
  - Loughla 7y ago
    I would agree with that. During the last election cycle (and already this one), the one thing the polls consistently got wrong was just how pissed "Joe-Midwest Average Voter" is that his life is much worse than his parents' were at the same age. When people online and in the news express how they just don't understand why people still support Trump, it's because they're not trying to understand. If all you care about is disrupting as much of the system as possible and pissing people off as much as possible, you're getting exactly what you wanted.

contravariant 7y ago

Your formula has the opposite problem, by looking at cases that have a known outcome you are biasing results towards cases that end quickly (in particular cases that end in death). For a proper estimate we should look at cases where the infection is known to have begun e.g. a month ago. Then the mortality rate should be somewhere between dead/infected and dead/(dead + recovered).

swader999 7y ago
There's also the possibility of reinfection and false negatives. The best data we have is not even close to perfect.
nik_s 7y ago
> Your formula has the opposite problem, by looking at cases that have a known outcome you are biasing results towards cases that end quickly (in particular case that end in death). Unless I'm mistaken, that would only be true if cases that end in death are much faster than the cases that end in recovery. I have found it difficult to find detailed statistics on the topic, so I cannot tell you that it's definitely true or not, but I agree that it's an important variable that should be taken into the equation.
- twotwotwo 7y ago
  With many viral respiratory bugs, symptoms appear a few days after infection, peak a few days after that, and then there's a long tail of sniffling and coughing. Deaths happening in the peak and recovery being declared nearer the end of the tail leads to the intuition that maybe deaths could cluster earlier than recoveries. Of course, I don't know how/when recoveries are being tallied right now and don't want to guess. Bigger picture: lots of factors go into a good estimate, and epidemiologists are not new to mathematical modeling. When back-of-the-envelope math doesn't get the same prediction as the consensus models of what's going on, we shouldn't assume the epidemiologists are wrong.

mns 7y ago

I do have one question and I'm asking this seriously, not to start an argument or to attack someone. I also saw this here in a lot of the posts about covid-19. We have numbers, but every time people tend to ignore them or say we should not trust the numbers, take them with a grain of salt, "I think this is way worse, it's going to get way worse" and so on. It's like there is this thirst for disaster or some global drama everywhere, and this is not something that I would expect from Hackernews. If the numbers don't align with our hopes or fears, we should take them with a grain of salt and trust the gut feeling of whoever comments. It's quite weird to see that when it comes to this, people seem to think that it's some sort of conspiracy, China is hiding numbers, now EU is not doing things properly, as I see it everywhere "my country can't have 0 cases, I know that our airport is a big hub and it can't be, we will be doomed as we probably have hundred of cases instead of none and our government is not doing anything". I'm not saying that this virus is not a threat and I worry for my parents as this could be a big issue for their condition, but we've gone down the rabbit hole with the hysteria in the press and online and it's scary to see this need for a global pandemic and the urge to constantly feed the panic monster.

dpau 7y ago
ever since the beginning of this crisis, countries have been either hiding or underreporting the numbers. lack of adequate testing means that clusters are discovered late, after the virus has had a chance to spread. it's not so much a thirst for disaster as it is a thirst for knowledge so that we can better prepare ourselves. even in the US, the CDC seems at odds with the president as to the severity of the virus and its spread. if anything, it's governments that are "aligning the numbers" so as to avoid mass panic, downturns in markets, etc.
- logjammin 7y ago
  What evidence can you point to of this "hiding"? Lack of adequate testing is a factor, I Grant you, and a big one -- but clusters are discovered late because it now appears that people can shed virus when they're not symptomatic.
  - 7y ago

wcoenen 7y ago

> a better approximation of evaluating your survival chances is to look at the death to recovery rate (dead / (recovered + dead)) This formula is still fundamentally wrong because it assumes that the time between infection and death is the same as the time between infection and recovery. I don't see why that would be true.

Retric 7y ago
The argument is it’s a closer approximation. Abstractly if the average death took place X days after infection and recovery took more than 2X days after infection then deaths:infection is a better metric. On the other hand if the average recovery takes less than 2X then deaths:recoveries is a better metric. And if it’s close to 2X then averaging them is a better idea. Of course detection also lags infection so that’s another consideration. I suspect that’s the real difference as outside of China a lot of cases where discovered before symptoms developed due to blood tests. PS: South Korea has 1,766 confirmed cases, 13 dead, and 26 recovered. Iran has 245 confirmed cases, 26 dead, and 21 recovered. Those numbers are far enough apart to suggest underlying differences in reporting, which is I a larger issue. https://en.wikipedia.org/wiki/2019–20_coronavirus_outbreak https://en.wikipedia.org/wiki/2019–20_coronavirus_outbreak

blattimwind 7y ago

I don't think a sensible mortality rate can be computed at this point, because we have no idea, not even good estimates, how many people contracted the pathogen. 10 dead out of 1000? Or 10000? Or 20000? In Wuhan they apparently checked ~almost everyone for symptoms - temperature - but showing symptoms != infected. So far it seems that there is an exceptionally large proportion of infected people showing no or barely any symptoms.

admax88q 7y ago
doesn't that mean that we can only compute an upper bound on the mortality rate? We will never know for certain how many cases there are, but _of the cases we know about_ we can compute a reasonable upper bound on mortality. Were more likely not to learn of cases than were not fatal than we are of cases which are fatal as severe cases are more likely to seek treatment.
- marcosdumay 7y ago
  With the measurement people are using, yes, you can only know an upper bound. It's possible to discover an actual estimate, but it takes time and resources. Researchers may care about doing that after the crisis passes, but it's very unlikely anybody will care about this right now.
  - admax88q 7y ago
    Which is fine, people keep pointing to all these unknown as "we can't possibly compute the morality rate!" Which leaves the door open for assuming its way higher than estimated, when in reality current estimates are likely an upper bound.
    - marcosdumay 7y ago
      Although I think the official estimates are severely overestimating the lethality (by an order of magnitude), I also think there isn't enough information for establishing an upper bound yet. Current estimates are bad.

CrazyStat 7y ago

> On the flip side, it's very likely that mild cases will never be reported, which in turn would decrease the mortality rate. Indeed. This calculation ignores severe underreporting of mild cases--for example, Johns Hopkins researchers (the same ones who made that map you linked to for data) estimated that only ~10% of cases in mainland China (mostly Wuhan at the time) were being reported [1]. That would put the mortality rate at under 1%, which is close to the evidence we have from elsewhere (e.g. the Diamond Princess). dead / (recovered + dead) is only a reasonable estimate if you actually have good numbers for the recovered count. We don't, so it's irresponsible to use it. [1] https://systems.jhu.edu/research/public-health/ncov-model-2/ https://systems.jhu.edu/research/public-health/ncov-model-2/

Alex3917 7y ago
> That would put the mortality rate at under 1%, which is close to the evidence we have from elsewhere (e.g. the Diamond Princess). Since it takes 3+ weeks to die from this illness, we're not going to know the fatality rate from the diamond princess for another month. And that's still going to be a lower bound since they'll all be getting medical care from often before they're even diagnosed.
- learc83 7y ago
  >And that's still going to be a lower bound since they'll all be getting medical care from often before they're even diagnosed. It's not a lower bound because cruise ships skew much older than the general population. All 4 who have died so far have been in their 80s.
  - Alex3917 7y ago
    Good point. That you can at least try to correct for to match various populations though.
- nswest23 7y ago
  We know the percentage of people who are in critical condition and it's very low.

cm2187 7y ago

Well the death rates seem to be lower outside of China so that doesn’t seem to support that China is understating the lethality of the virus, nor that it is particularly more lethal than the chinese numbers. Re the higher death rates in the chinese province, I thought it was due to people not showing up to hospital when having milder symptoms, but I watched an interview of a french doctor who suggested it is rather because of the lack of medical infrastructures in that region, to which the chinese remediated by building these spectacular field hospitals.

furyofantares 7y ago

I agree with your general point that rate=deaths/infections is making a big assumption about unresolved cases and almost surely gives a too low number -- but rate=deaths/recovered I think does the same thing in the opposite direction. Unfortunately we just don't know right now. It would be nice to see deaths vs recovered vs mild cases vs critical cases for people who have been infected >N days, but that's much more nuanced information to consume than some "death rate". Btw, you made a point about exponential growth, but is that happening? The logarithmic graph on https://www.worldometers.info/coronavirus/ https://www.worldometers.info/coronavirus/ appears flatlined to me. Maybe (probably?) that's just about containment in China, but when we're discussing death rates that's where most of the data is.

ghostpepper 7y ago

I have heard this argument that the real mortality rate may be under-reported for this reason since the outbreak began around the start of January and it makes sense to me. On the other hand, what do you say to the claims that the real mortality rate is much lower due to people infected but with symptoms so mild they don't seek treatment?

Alex3917 7y ago

Right. It takes 3+ weeks to die from CoVID-19, so if they're looking at people who were diagnosed as late as Feb. 11th then this is going to be a substantial underestimate of fatality. Especially since as awareness of the disease has increased, the time to diagnosis after first symptoms has fallen from 5 - 6 days to 1 - 2 days.

wtvanhest 7y ago

5 people have died that were on the princess cruise out of 705 infected. At just over 1/2 a percent, it is more deadly than the flu, but not 2% and certainly not 7.8% The princess cruise gives us a crucial piece of information which is a fully tested population. 2 things to consider: 1) population is like older due to being a princess cruise which would increase death rate. 2) not everyone is cleared yet, so more deaths could come

generalpass 7y ago
And how healthy are their immune systems? I imagine they are eating a lot of sugary foods, drinking more than usual and staying up later in a time zone they are not acclimated for.
learc83 7y ago
Only 4 have died, and all 4 were in their 80s.
- wtvanhest 7y ago
  You are correct: https://bnonews.com/index.php/2020/02/the-latest-coronavirus-cases/ https://bnonews.com/index.php/2020/02/the-latest-coronavirus... I must have remembered the wrong number. 4/705 = 0.5% (1/2 a percent), which is still pretty high vs the flu, but not 2% or 7.8% or whatever crazy numbers people are quoting.
TheHypnotist 7y ago
Wouldn't the quick discovery and level of care also factor in?

0x8BADF00D 7y ago

The infected might be terribly maimed for the rest of their life as well. Can you imagine if they develop COPD or some similar chronic inflammatory lung disease because of this?

mrb 7y ago

You are exactly correct. With the formulas you described: naïve CFR = deaths / cases resolved CFR = deaths / (deaths + recoveries) It can be shown pretty dramatically in outbreak simulations how more accurate the resolved CFR is than the naïve CFR. See for example the chart https://blog.zorinaq.com/assets/outbreak2.svg https://blog.zorinaq.com/assets/outbreak2.svg In that specific example, the naïve CFR underestimates by 5x, while the resolved CFR is only off by ~1.3x. I ran this simulation as part of my blog post on how to estimate the Case Fatality Ratio of the coronavirus: https://blog.zorinaq.com/case-fatality-ratio-ncov/ https://blog.zorinaq.com/case-fatality-ratio-ncov/

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partiallypro 7y ago

The survival rate is also probably thrown off though because some countries have better trained health professionals. No one in the US (that made it to US care) has died as of yet. In other countries without advanced facilities available, the rates are much higher. If the disease hits Africa and more of the ME, the rate will go up. While in the US, and richer countries like Germany, etc the rate will probably be low.

WaltPurvis 7y ago
There's some validity to that, but a lot depends on how widespread the disease becomes. There are about 100,000 ICU beds in the US, and they can't all be allocated to coronavirus patients. Not having access to a ventilator would be pretty much equivalent to a death sentence for some patients. There are <100,000 ventilators in the US, and they're not evenly distributed (some areas and hospitals have very few). It wouldn't take much of a pandemic to exhaust our supply of ICU beds and other critical-care resources.

john_moscow 7y ago

The dead / (recovered + dead) is the worst-case assessment, since most of the people who have not technically recovered yet (but may not even have any symptoms anymore), won't die either. The dead / (infected + dead) is the best-case assessment, since some of the people who have not recovered yet, will die. A somewhat better metric would be dead / (infected X days ago) where X is the median time for the illness to fully develop.

yurlungur 7y ago

To me this article seems to be missing the most important stat from the original article, which is that the case fatality rate as measured is 2.9% inside Hubei (possibly under-reported) and 0.4% outside. I think this strongly suggests that, as one would expect, the situation is much worse if patients lack the medical resources for care. And it also shows how important quarantine and preventative measures are.

ummonk 7y ago

Dead / (dead+recovered) is overestimating (even assuming 100% detection of mild cases) because it takes longer for people to recover than to die from it.

gentleman11 7y ago

You have to take into account that 80% of cases are not severe, so you could have it and just think it was the flu. Most people wouldn’t go to the hospital in that case, so that 7.8% figure is not realistic. The WHO numbers (2%) do at least try to take this into account I’m legitimately confused why we’re seeing these responses make top response on hn. It’s WEIRD

baxtr 7y ago

You assume recovered data is correct? Maybe it takes longer to be counted as recovered than it takes on average to die. This could change the rate

stewbrew 7y ago

How would you know the number of infected people? You know the number of infected people with symptoms that were severe enough to get tested. For the same reason: How would you know the number of people who have recovered? You know the number of people who were observed and then recovered.

divbzero 7y ago

On another page [1] Worldometer correctly explains the better estimate of mortality deaths / (recoveries + deaths) for ongoing outbreaks. Not sure why they got it wrong here. [1]: https://www.worldometers.info/coronavirus/coronavirus-death-rate/ https://www.worldometers.info/coronavirus/coronavirus-death-... "Coronavirus Mortality Rate"

nswest23 7y ago

How on earth is this the top rated comment? You can't make up your own statistical measure for mortality rates for a novel virus unless you're an epidemiologist. Of course there is under-reporting of mild cases...there's a shortage of test kits!

zachwill 7y ago

Built a simple `PyMC3` model based on your comment: https://github.com/zachwill/covid-19 https://github.com/zachwill/covid-19