Substantial undocumented infection facilitates rapid dissemination of SARS-CoV2
science.sciencemag.org
science.sciencemag.org
(86% of cases unreported, eg about 1 in 10 reported, assume that number of unreported fatal cases is 0)
Edit: closer reading suggests the optimism is sadly unwarranted, the headline under-reporting number of 86% is from the early pre-travel ban model, post-travel-ban estimates give a 65% detection rate, combined with the increased number of cases in this later period this implies that naive mortality estimates are more like 2x off than 10x off.
S.Korea did extensive testing, which reduces the number of unreported infections. So the calculated death rate in S. Korea is 4x lower than a comparable country like Spain, which has similar # of confirmed cases, population, GDP, and GDP per capita.
If we assume S. Korea's calculated death rate(<1%) is closer to the true death rate and apply it to other countries to derive the total # of infections (reported + unreported) based on the reported death count, we can see there may be far more infections than we know.
Is Spain and S. Korea really that much different to have a 4x difference in death rate?
The former suggests what your population mortality rate will be if your healthcare system is overwhelmed, and could possibly be derived from Italian data. The latter gives you a resources vs effectiveness sweet spot that maximises health system throughput, so you can save the maximum number of lives over time given the resources you have (or can build/find.)
The age profile is relevant, but worryingly there seem to be a number of reports that it's not just the over-65s who are at risk.
I haven't seen anything more recent about this than the Chinese estimates from a month or so ago.
We by all means should collect more data, just don't shoehorn it into such a very primitive yet very essential statistic. Give them new names and new, more appropriate semantics. I suspect that after this is over they're going to tighten the criteria around CFR, and in particular exclude by definition asymptomatic cases and possibly non-hospitalized cases. They never had to do that before as "cases" usually implied someone sick enough to be given a diagnosis, which in turn implied someone at least moderately sick--e.g. actual or suspected case of pneumonia.
One study I've seen pinned the median time-to-death after symptom onset at 18 days. Even in Korea you won't get less than a 2-3% CFR with that estimation.
edit: I don't know anything about statistics by the way, please tell me that I'm wrong.
https://www.businessinsider.com/coronavirus-death-rates-by-a...
20-29: 0%
30-39: 0.1%
40-49: 0.1%
50-59: 0.4%
60-69: 1.5%
70-79: 4.3%
80+: 7.2%
ie: if you have cov2 you have a 7% chance of dying from it but dont you already have say a 50% chance of dying in your 80s anyway?
to be strictly logical and not emotional about this moral question: are we unhinging society (effects we cannot begin to calculate) to keep the fatality rate for the population 80+ at 50% instead of 57%?
in terms of costs to the healthcare system, might this equate to a net relief if the peak were accelerated instead of flattened?
That's a standard actuarial problem, answered with life tables (https://www.cdc.gov/nchs/data/nvsr/nvsr61/nvsr61_03.pdf -- pdf, US 2008). In said life tables, there is a 7% death rate between ages 83 and 84.
To an order-of-magnitude approximation, infection with the novel coronavirus seems to impose roughly one year's worth of mortality risk on the victim.
It’d be interesting to see how many healthy 80+ year olds have died.
There's a ~6% chance of dying during the year you turned 80. That chance goes up dramatically every year you get older. By 85 it's nearly 10%.
It would be interesting to calculate how this virus changes those rates. I feel like these kind of analysis are completely lacking in any reporting.
And then it's also about the rest of the population that needs medical attention for a different reason.
Imagine the medicial facilities being flooded by COVID-19 patients. There are enough severe cases already in many countries that non essential operations are suspended.
Good luck getting adequate treatment for your broken leg.
https://www.statnews.com/2020/03/16/coronavirus-model-shows-...
And all of that is ignoring the possibility of people suffering nonfatal chronic health problems, which has been reported.
Meanwhile, remdesivir and lopinavir/ritonavir are in trials and once we actually have drugs available the hospitalizations would be shorter and the death rates much lower. At that point quarantine becomes less important.
80 5.8%
81 6.4%
82 7.1%
83 7.8%
84 8.7%
85 9.7%
86 10.7%
87 11.9%
88 13.3%
89 14.8%
1) But # infections were growing exponentially, we need to use numbers from the same cohort, which implies much lower # infections & higher CFR. Naive CFR will go up once infections grow more slowly. (It is already going up over time.).
2) South Korean confirmed cases are much younger than their median age, mainly between 20-29 years old (perhaps because of where superspreading events happen—that church). This age group has a much lower fatality rate from Covid-19.
3) # hospital beds per capita in South Korea is second highest among OECD countries (1st is Japan) and ~4 times that of the US. They already have patients waiting for beds.
Most countries will do much worse if they reach the same # infections per capita, since fatality rate surges to multiple times as high without proper care (as can be seen in several places around the world now, unfortunately).
(SK has ~12 beds/1000 capita; China ~4.3; US ~2.8)
CFR (Case Fatality Rate) is based on the # people who were tested. IFR (Infection Fatality Rate) which includes people with no or mild symptoms will be lower.
"On this basis, using WHO data on the cumulative number of deaths to March 1, 2020, mortality rates would be 5·6% (95% CI 5·4–5·8) for China and 15·2% (12·5–17·9) outside of China. Global mortality rates over time using a 14-day delay estimate are shown in the figure, with a curve that levels off to a rate of 5·7% (5·5–5·9)"
https://www.thelancet.com/journals/laninf/article/PIIS1473-3...
According to this article (https://www.businessinsider.com/coronavirus-death-age-older-...) an 80 year old has a 15% chance of dying. Is that actually "extremely bad" though? I think if 80 year old grandma got cancer and the doctors told you there was a 85% chance she'd recover, you might well breath a sigh of relief. For somebody that old, there are much worse mortality rates than that. Breaking your hip is more deadly than getting the coronavirus for people that old[0].
Rather the legitimate concern is due to how rapidly the disease is spreading. 15% is enough to kill TONS of people when you scale it up to the whole population. It's a high mortality rate considering the scope of the pandemic, but a relatively low mortality rate for the individual.
[0] "The risk of death in the year following a fracture is about 20% in older people." https://en.wikipedia.org/wiki/Hip_fracture
On an individual level however, adding an illness with 15% mortality on top of all the other things over 80s can get is a big deal.
80+ year olds are a varied cohort, and some are reasonably healthy, with multiple years left to live. The hip fracture data is biased because frail people with other problems are more likely to fall.
Yes.
How much money would I have to offer you that you took your chances?
Unnecessary deaths are worse than life threats you can't do anything about it.
That depends on how old I am. If I'm in my 80s with a fulfilling life behind me, playing russian roulette would disturb me a lot less than if were a young adult with a potential life before me. From elsewhere in this thread, it seems like simply being that old in the first place is like playing russian roulette anyway (https://news.ycombinator.com/item?id=22600562)
Now obviously in this case you'd be playing it twice instead of just once. But I hope that by the time I'm that old I've had enough time to come to terms with my mortality, write a will, make amends with family, etc. Because there are much worse prognosis's for somebody at that age than 15% mortality rate.
Or to look at this from another angle: 'extremely' bad is inherently relative. And taken relative to other common ailments people that old content with, I don't think 15% chance of death qualifies as 'extreme'. If 15% is 'extreme' then what adjective would you use for a cancer with a 50% mortality rate? "Super-dooper-uber extreme"?
You're missing the time frame. Getting cancer is a threat that many old people face but that's spread over decades.
With COVID-19, we face 70%-80% of the population being infected within a much shorter time, possibly a year or less (depending on how well or bad the delay measures are).
Yes, people die at that age for many reasons. But here, we have a potential death threat that is avertable and, most importantly, that affects the whole of society, not only old people.
Don't think that only old people get it and need medical attention. Lots of young people also need medical attention, even if they don't die from it. Ignoring long term effects from having caught it (as we don't know them yet), this alone would disrupt society. And then the secondary effects of people with other medical conditions not being treated as they are triaged.
Modern society doesn't need a lot to be disrupted. Look at how disruptive 9/11 was.
The most likely explanation is that Korea is catching more mild cases that other countries are missing.
While I agree with your overall point, I don't believe this is a good assumption. I think some percentage of unreported fatal cases are reported as pneumonia/cardiac arrest/etc.
It's certainly not uniformly distributed. Testing is not random. Typical test guidelines are to test when some combination of the following are present:
* Flu-like symptoms, after ruling out all other infectious causes
* Travel to a known outbreak region
* Close contact with a confirmed or strongly-suspected case
Asymptomatic people without known exposure are left untested (as is sensible to economize resources), and even people with mild symptoms but no known exposure may be left untested -- this makes it particularly difficult to catch the early stages of community spread, before people have had time to be hospitalized.
You seem to be implying that maybe there are a load of us that had it already (and maybe, hopefully, that’s the case). But if so, doesn’t it seem weird that we’ve basically watched its progress as it’s spread around the world? Why would most people get it and be asymptotic followed by a series of unlucky people that are getting it now and falling ill? Though again, maybe I’m misunderstanding.
> You seem to be implying that maybe there are a load of us that had it already (and maybe, hopefully, that’s the case).
Yep, and that as a result our mortality projections from CFR are quite overstated.
> But if so, doesn’t it seem weird that we’ve basically watched its progress as it’s spread around the world?
I wouldn't be shocked to see a retrospective on this in the future tell us that we've been seeing the spread of availability of the test rather than the disease.
> Why would most people get it and be asymptotic followed by a series of unlucky people that are getting it now and falling ill?
Symptoms are basically the same as the flu for most people (Korea has a 0% CFR under 29, and 0.1% under 49), and for older folks, well, they're older, and basically anything can kill them. Some studies showed a fatality rate of 10% for the H1N1 flu -- and so far we're seeing a CFR of 15% for old folks in Korea. It's possible the fatalities we'd been seeing were written off as just that.
Ok, I could buy into that (and I really hope that's the case - though I'm still doubtful). The main thing I didn't realise was that the tests didn't show who had had it. Thanks for taking the time to work your point through with me.
So, no.
This paper is about undetected carriers spreading SARS-CoV2 across China prior to the Jan 23 lockdown. It does not imply that 86% of all total infections that we see currently are undocumented, it only reflects the relatively narrow testing that was happening prior to Jan 23 (likely only the severe cases).
After Jan 23, China expanded its testing much more broadly, and other countries (such as South Korea) have done so as well. You should not take this paper to mean that the actual number of cases for these countries is larger by a factor of 1/(1-0.86).
We should be conscious of this desire, and be careful assessing new evidence that comports with this notion.
But this isn't a bad thing -- having strong opinions and questioning the veracity of data is key to having informed, strong opinions.
And, hearteningly, we see that OP has edited his comment to reflect the knowledge you passed along and has a better understanding of the situation. Inquiry at work.
https://drive.google.com/file/d/1DqfSnlaW6N3GBc5YKyBOCGPfdqO...
This also explains why Korea’s [edit: case fatality] rate is so low and so correlated with their high incidence of testing.
I wouldn’t be surprised if the majority of us have already had it. There’s a decent shot this all amounts to a big ol nothing burger.
It sounds like you may be interested in reading this paper: https://www.medrxiv.org/content/10.1101/2020.03.04.20031104v...
>I wouldn’t be surprised if the majority of us have already had it. There’s a decent shot this all amounts to a big ol nothing burger.
Unsupported by any evidence and complete wishful thinking. Please stop with the irresponsible speculation.
I won’t bother re-creating the epidemiological studies as professionals have much better simulations than I could offer.
I will urge you to read up on the models before assuming this thing is “already everywhere” which also implies it won’t grow exponentially.
100% complete bullshit, nobody can know this kind of thing for sure right now.
The danger with this disease seems to be that it is highly contagious and countries tend to see a huge spike in cases that completely overwhelms the healthcare system and leads to a several-fold increase in the case fatality rate (e.g. Iran, Italy).
So I agree that on its own COVID-19 is likely less fatal than some of the numbers we tend to see cited, but under outbreak conditions it can be much much more fatal.
I mistyped in my original post which I have since edited.
> Presently, there are four, endemic, coronavirus strains currently circulating in human populations (229E, HKU1, NL63, OC43). If the novel coronavirus follows the pattern of 2009 H1N1 pandemic influenza, it will also spread globally and become a fifth endemic coronavirus within the human population.
This thing is extremely contagious, it's probably already everywhere, and there's a good chance it will be circulating indefinitely. Hopefully folks will just get tired of the panic after a while. And if we're lucky, this might lead to more awareness about the devastation that respiratory illnesses cause, especially to old folks, every year across the world.
If you want to yell at me because I'm not panicking enough, save your breath. I'm just as pissed at you for spreading a terrible mind-virus, so call it even if you must.
The death count math and growth rate doesn't check out. If that were true (i.e that the total infection rate was already non-negligible) then the disease must have either been growing for months without detection and without spreading from Hubei, or it must in some crazy way be spreading much faster among the asymptomatic than among the serious cases.
The article argues for a roughly 6x undercount. That's still much lower than saturation, meaning that we have a lot of headroom to grow out of control still.
Stay. At. Home.
Would that be surprising? If you're contagious a few days before any symptoms, you'd have plenty of time to transmit it to several other folks. Even if your case then becomes serious (which is not terribly likely in this model), you're going to be staying home or in treatment, and probably much more careful about contact with others.
I know they have found people like that but I'd still be leery about going from data to a pronouncement since I assume the data just isn't extensive or reliable.
As https://komonews.com/news/coronavirus/seattle-flu-study-alle... shows, the USA was refusing to test Americans in Seattle while COVID-19 was actually spreading. When the Seattle flu study tested they found that it had already been locally spreading for weeks. And in fact most people who think that they have COVID-19 in the USA are unable to verify whether or not they have it.
I personally wouldn't be surprised to learn the number of people who had it or have it now is hundreds of times higher than the "confirmed cases". I would also speculate that this virus has been in wide circulation for months now.
But my guess is as good as anybody else. Until we get actual, statistically valid high quality data.... all we have is speculation. I sure hope we are making the right call shutting things down as much as we are. People have to remember that there are serious physical health consequences to the actions being taken. Suicide rates will climb, alcoholism & addiction will jump, crime will go up, etc.
A few weeks of this kind of economic pause is one thing but at some point in the very near future people are going to want to know what the end game is.
Perhaps elderly people often trickle in to ICUs with respiratory issues and as long as it’s flu season no one really notices some more dying 80+ people especially as there was no test for this virus?
My perspective is someone in Seattle that had the worst asthma attack of my adult life a month ago. Literally couldn't breath well enough to talk for about a week with fever several nights. I've now seen my family get all symptoms but the breathing difficulty, fevers included. We can't get tested, as they are still mostly stonewalling. And I would likely be negative, even if I had it, at this point.
So, if I had it, and my family did too, why did I get severely hit, but they did not? Best I can fathom is baseline lung health.
Would love a better hypothesis. Or more tests I can look at.
The "mild cases" in the statistics include people with pneumonia.
A few minutes later: keep in mind that there are ~1 billion colds a year in the US. Covid-19 isn't the only explanation for an illness, and not even the likely one.
So, no, I did not get hit severe in that I didn't die. I'm having a hard time thinking I just had a bad cold. Especially when I have seen all four of my kids get coughs and fevers since...
The closest I have come to this level of sick was a decade ago when I got walking pneumonia. And that was easy comparatively.
Bad reasoning?
I accept I might not have had it. And if we start seeing exponential increase in severe cases, I'll fully accept that. Until then, the evidence still looks heavy that I had it.
I imagine most countries keep track of flu deaths and would have noticed an uptick.
Could be, but not necessarily because coronavirus and flu target the same pool of people.
Those on risk groups had being first filtered (indirectly killed) by the economic scam. People unable to accurately heat their home in winter for example would suffer more pneumonias and having a logical explanation, nobody would care to search for a new virus among those cases.
Increase in coronavirus kills could be mitigated by other previous conditions and masked with a decrease in flu kills (by previous decrease in the pool of posible flu victims).
On the other hand, the virus appearing in Wuhan market was always of problematic explanation.
One hypothese could be that the market was linked with the labs somehow (origin in the labs). I always though this as a possibility worthing to explore.
... but I'm starting to think that another hypothese could be that Wuhan was not the first location, but one of the few places equiped to identify the virus and understand that was something more than a common cold. Virus taxonomy is really expensive, not much people can do it with new viruses and most hospitals will not care to test for just a strain of a common cold.
Is a question I haven't asked. Do they usually see more pneumonia than places like the states, anyways? Could be a proxy to test my hypothesis.
The US has three times as many ICU beds per capita as Italy. https://web.archive.org/web/20200313034908/https://www.forbe... I don't think it's a coincidence that Germany, which has performed much better than Italy, has almost as many as the US.
So, my hypothesis centers around trying to give an explanation for why that population isn't impacted by severe cases. Going off how bad it hit me, if that is what hit me, best I have is lung health. And I don't have unhealthy lungs, all told. I do, however, have a distant history of asthma, and I find it plausible it did damage my lungs long ago.
To flip it some. They say even if you survive, you may have lasting lung scarring. What if that preceded the covid?
That doesn't make sense. Covid follows the same exponential curve in all countries. If the US has a bunch of latent infections, but no huge surge in pneumonia, then that would imply there is something special about Americans that keep them from developing the worst symptoms, or something special about American old people that, despite contact with the young silent carriers, they do not develop the disease. There is no reason to believe either of those are true.
They say we are a week or so behind Italy. Italy is experiencing hospital overruns. If the week-behind estimate (based on actual numbers) is overly conservative, then we would have expected to see hospital overruns in the United States from old people with pneumonia. However, we don't have that. Thus, if the week-behind estimate is overly conservative, we are certainly not at the same point as Italy or ahead of Italy, so we can say that we are anywhere from 1 week to 1 day behind Italy which is still a pretty good bound.
The week behind curve on Italy is one to watch. My assertion is that we have had infections hitting here for at least a month. Probably longer. If we don't get the same severe case spike in a week, will everyone just keep upping their models? Because that is what it looks like people are doing.
My hypothesis is a higher baseline lung health will result in a milder wave of infections. Essentially, it is not young that are getting milder cases, it is people with less damaged lungs.
And no matter how you slice it, the places that have had the most deaths, have by far the worst air quality.
So, my hypothesis is on base lung damage. And is spurred by kids not getting hit. I find it hard to think kids aren't getting sick.
Note also that I'm questioning if we will see an exponential rise in deaths. In large, I don't think that will be seen outside of places with poor lung health, if my hypothesis is right.
But I’m thinking they probably test at least bad cases for almost every common virus so they would have been alarmed by even a few deaths from pneumonia without positive tests. This is why I don’t believe the theory that many were infected long ago.
https://www.reuters.com/article/us-health-coronavirus-usa-nu...