In 4 US state prisons, 3,300 inmates test positive, 96% without symptoms

https://www.reuters.com/article/us-health-coronavirus-prisons-testing-in/in-four-u-s-state-prisons-nearly-3300-inmates-test-positive-for-coronavirus-96-without-symptoms-idUSKCN2270RX

by throwaway888abc • 6 years ago

785 587 6 years ago

reuters.com

alexbanks3• 6 years ago

Before the deluge of "But wait two weeks" comments, I just want to ask at what point we accept that the potentially of totally asymptomatic cases is insanely high, far higher than anyone thought?

taeric5• 6 years ago

I also want to add that this doesn't make the virus less deadly. It just gives it a very population varied IFR. It appears far more deadly for some populations. Near harmless for others. But no clear way to confine it to the harmless crowd.

vmception2• 6 years ago

But no clear way to confine it to the harmless crowd.

That won't be what the public policy decisions will be based around if the asymptomatic and already exposed rate is so high.

We don't know enough to make that decision yet, but testing more broadly was the first step.

Remaining steps:

- Do they get sick in two weeks?

- Skip testing for current sickness, and test for antibodies instead.

- Get a better antibody test that is more accurate

- Understand how well antibodies work, and for how long

and then we can make decisions, even if they are as simple as "this is a systemwide over the air update, some people will get bricked"

it's becoming clear that we might end up with a society where the average BMI is under 24.9 simply due to the lower oxygen and resource requirements to support those body systems.

SpicyLemonZest16• 6 years ago

Like with the death rate, I expect we'll seamlessly transition from "this isn't proof, in 2 weeks you'll see" to "this isn't news, everyone always believed that so it doesn't imply any changes in strategy".

wegs6• 6 years ago

Well, it isn't proof. It is evidence, though. And in two weeks, we will have a lot more evidence.

A lot of this is like Russian Roulette -- there's a huge amount about this virus which we don't know, and it could be super-bad or not-that-bad. It could also be there are bad and not-so-bad strains. Or it could be bad down-the-line.

Until we do have proof, I'm advocating being conservative. In 2 weeks, we'll know if people are turning up in ERs or in morgues. In a few months, we'll know about lung damage, immune system damage, strokes, or a lot of the other potential consequences. In a year, we'll know about vaccine and long-term immunity.

I think the key problem here is failure to understand risk management. I can believe one think, but act another way just in case I'm wrong. Or I can be unsure. And so on. That nuance is lost in the right/wrong discussions.

AnthonyMouse• 6 years ago

Before the deluge of "But wait two weeks" comments, I just want to ask at what point we accept that the potentially of totally asymptomatic cases is insanely high, far higher than anyone thought?

Presumably in two weeks, when we know whether more of these thousands of people go on to develop symptoms or not.

Is anybody following up on stories like this? Do we have any from two weeks ago?

onlyrealcuzzo• 6 years ago

The asymptomatic rate being that high and that many people being infected implies three things.

1) that the asymptomatic rate for this Coronavirus is much higher than other Coronaviruses.

2) but at the same time, it's more deadly than most Coronaviruses.

3) and it's also the R0 is much higher than other Coronaviruses.

Isn't it more likely there's a testing issue? This seems a lot like a person that runs a SQL query that overturns all established data at a business, and instead of first assuming that their query is wrong, they instead assume everyone at the business is wrong.

I'm not saying the tests are inaccurate. I'm saying when you get highly conflicting data that has critical implications, you shouldn't jump to conclusions. And you should prepare for the worst case, not assume the best.

jacobolus2• 6 years ago

Is anybody following up on stories like this?

The best follow-up we have is from the cruise ship, where at the time of testing more than half of those who tested positive were asymptomatic, but ultimately something like 80% of the confirmed infected ended up with symptoms.

tyingq• 6 years ago

There's also the nuance of US state prison care quality. "Without symptoms" could just mean "not obviously gasping for air".

londons_explore• 6 years ago

"Not dead yet"

Pfhreak2• 6 years ago

This is absolutely my reading. That someone is not really observing or listening to prisoner symptoms with much care either because of distrust between the prisoner and the medical technicians or because prisoners receive such poor care.

code_duck5• 6 years ago

Sure, in New Mexico there are routinely lawsuits against the state and county’s for completely ignoring inmates’ communicated medical needs (or worse).

https://www.santafenewmexican.com/news/local_news/what-happe...

lostlogin2• 6 years ago

Amnesty International campaign against this and are currently calling for the release of ICE detainees. Judging by a skim of their releases even those obviously gasping for air don’t necessarily get the care they need. It’s a truely massive system which in itself is part of the problem, though the exceptionally low bar for the care of prisoners is Amnesty’s primary angle.

https://www.amnesty.org/en/latest/news/2020/04/usa-covid19-p...

sroussey• 6 years ago

It’s always high on these antibody tests, low on tests approved by the FDA.

cjlars• 6 years ago

I'll venture a guess that by Wednesday the news cycle will be deep in the implications of very high asymptomatic case count... Assuming we don't start seeing contradicting evidence.

vanniv6• 6 years ago

Nah, that has too much risk of admitting that eternal house arrest isn't a good solution, so we can be certain that won't be the media narrative.

ouid• 6 years ago

You have to account for events like the Diamond Princess, if you want to run with that story.

FabHK4• 6 years ago

It’s not like this is the first population that has been nearly exhaustively tested. There was the cruise ship, there was the navy ship, etc. Those have shown between <20% (among the elderly cruise ship demographic) to 60% (among healthy soldiers) asymptomatic.

This certainly adds another data point, but I wouldn’t throw conventional wisdom out the window yet.

Terretta• 6 years ago

Note that until this past week, officially, the symptoms had to be the first three defined by CDC, not the eight or so CDC have expanded now: fever, cough, shortness of breath, chills, repeated shaking, muscle pain, headache, sore throat and new loss of taste or smell, could all appear between two and 14 days after exposure.

In the field it appears many/most of the less severe cases don’t exhibit the initial set they had defined, so patients experienced illness written off as not COVID-19.

From what I’ve heard from the field, a careful patient history finds there was typically a bout of unusual “but it can’t be COVID” illness with a set of the expanded set of symptoms in almost every “asymptomatic” patient.

It’s further speculated these variations may have to do with level of exposure and path of infection, along with the earlier noted lung health and comorbidities.

FrojoS4• 6 years ago

Very interesting point. If this is how symptomatic was defined, yours should be the top comment of the thread.

alkonaut3• 6 years ago

at what point

When at least one large studied group has an outcome (symptomatic recovered, asymptomatic recovered, or dead). So for this group I guess a few more weeks.

fzeroracer5• 6 years ago

When we know the full extent of the virus? It's an easy question to ask, but an incredibly hard one to answer.

For example, they've been finding that the virus can trigger strokes in otherwise healthy individuals. That's individuals that either exhibit no symptoms or minor symptoms. So while they may otherwise be asymptomatic, we can't know unless we do a full extensive test to see if they're also suffering from unseen clotting issues.

marcell4• 6 years ago

I've been tracking the antibody study results in a spreadsheet, and they are suggesting a 10-20x undercount of cases in the official "confirmed" numbers. You can see the data I've collected here: https://docs.google.com/spreadsheets/d/16onEUBWIV5IqN1RCvTla...

bb2018• 6 years ago

I think antibody tests will soon become more useful for tracking disease progression in a population than the viral tests. The collection methods may skew things but they still are much more close to a random sample than the viral tests which have lots of issues with test shortages and people unable to get tested (or not wanting to go to the hospital with mild symptoms).

garmaine• 6 years ago

They have huge false positive rates though.

buboard2• 6 years ago

i don't understand the value of this multiplier. Case statistics are not an official census, it's incidental , depending on the criteria with which each region makes tests. Case numbers are unimportant, it's the total infections and consequent deaths that matter

SpicyLemonZest16• 6 years ago

You're probably right that they shouldn't be, but case statistics are regularly treated as an official census. I've seen many news articles in the vein that suchandsuch country is handling it better or worse because of their case numbers, or statistics like CFR that are computed from official case numbers.

analog312• 6 years ago

One reason is that early on when the curves looked pretty much exponential, folks were trying to pin down how bad it could get, and when. This was when the worst case scenario was for nearly the entire population to get it. I'm not quite sure we're completely out of that woods yet.

skybrian• 6 years ago

I wonder which tests they used? A recent study is finding that some antibody tests are much better than others when it comes to false positives:

https://tildes.net/~health.coronavirus/o6a/coronavirus_antib...

marcell4• 6 years ago

I know that the California studies used the same test kit. It had 2 false positives out of 371 samples of pre-covid19 cases, and has a 10-20% false negative rate. Because the case numbers are so small, the false positives can skew things quite a bit. I took the midpoints of their 95% confidence intervals in the spreadsheet.

I don't know what tests the other studies used.

DanBC2• 6 years ago

What numbers are you using for sensitivity and specificity?

marcell4• 6 years ago

It depends on the study, I've been using their reported confidence intervals. The two California studies (Santa Clara and Los Angeles) used the same kit, which has 2 false positives of 371 tests, and 10-20% false negative rate.

cies4• 6 years ago

I did similar calculations, and found the institutions in charge give us very unreliable data. The term "corona case" is very, very, ambiguous and cannot the understood as such without a detailed explanation on how the counting was done.

Thanks for sharing.

I found the peek in all-case mortality also very interesting, because that way counting is much more unambiguous: dead is dead.

They showed a clear diversion from the "average" in recent weeks, but... they did not show the stdev for the averages. Finally I found a chart that shows that "outliers" are not uncommon.

https://imgur.com/IPNiXRe

marcell4• 6 years ago

Yea, I agree that the case counts are very different between regions. I think the more interesting column is the IFR estimate based on the antibody study results, since dead is dead as you say.

It is interesting though that the median undercount is converging to ~10-20x. Perhaps the protocols across regions are similar enough that the confirmed case counts are somewhat comparable.

bobongo3• 6 years ago

because that way counting is much more unambiguous: dead is dead

Unrealistically low death stats coming from Turkey compared to cases easily refute that argument.

Dead is dead, unless the state finds a way to claim that it was not a COVID19 dead.

rjtavares• 6 years ago

Outliers such as this one are not uncommon in the winter. They are in April. According to that chart there isn't a single point outside of winter months as high as this year.

FrojoS4• 6 years ago

Is this for the US? Do you have a link for the source?

GuB-424• 6 years ago

Here is for Europe if you are interested. There are charts for excess morality by country, by age, and by year.

https://www.euromomo.eu/

There is a very noticeable spike in the worst hit countries: Italy, Spain, France, Belgium, Netherlands and the UK. The cumulative excess deaths for all Europe in the last two months matches the COVID-19 reported deaths (around 100000).

amscanne• 6 years ago

That chart is funny. The title is “unprecedented spike”, but it just shows that such outliers have occurred regularly.

joe_the_user3• 6 years ago

Your sheet is interesting. Looking at it, the IFR varies from 1.66% down to .11% and the 0.11% is for the Santa Clara, which many considered rather suspect.

The 1.66%, otoh, seems reasonably in line or at least compatible with what's been observed in Korea and elsewhere.

Given age is going to skew things a good deal, it seems like a picture is emerging but not that new a picture. An IFR of even 1% is pretty bad, especially given these statistics show how infectious this virus is.

gst• 6 years ago

The numbers that are quoted for Austria (which has the listed IFR of 1.66% in the document) weren't obtained via antibody tests, but via PCR tests. Here's a better source than the one linked in the document: https://www.sora.at/uploads/media/Austria_COVID-19_Prevalenc...

Most of those tests were done on April 4th and 5th which was 3 weeks after Austria started relatively strict lockdown measures, which also impacts that number, as this will result in the test to find an even lower number of positive people.

newacct5834• 6 years ago

An IFR of even 1% is pretty bad

To be clear: it would be the most dangerous general epidemic disease since the advent of vaccination, and by a significant amount. You need to go back to measles and polio to find general population outbreaks that were more lethal.

jMyles• 6 years ago

Here's a similar spreadsheet, with less detail but more studies:

https://www.reddit.com/r/LockdownSkepticism/comments/g6eqtt/...

It may be helpful to you.

Thank you for tracking these metrics.

bagacrap• 6 years ago

you have the prevalence for NY state but the row is called NY city. The NYC prevalence was 21.2

analog312• 6 years ago

It's interesting that this jibes with conventional wisdom. Since nearly the very beginning of when people started looking at graphs of case counts, my colleagues and acquaintances (mostly scientists) assumed a ratio of roughly 10x. Folks would look at any graph and automatically bump it up by an order of magnitude.

kortex• 6 years ago

Maybe we can institute a work-recovery program where inmates can do high-exposure work (once they are truly recovered). give them experience and a feeling of duty and purpose.

Nah, they'll probably just keep using em for slave labor.

OrgNet2• 6 years ago

I wish I could get an anti-body test done because I had flu-like symptoms before any tests were available

adamnemecek• 6 years ago

No, they will develop symptoms. Test again in two weeks.

DoreenMichele4• 6 years ago

I'm in a high risk category with an incurable respiratory condition. I'm convinced I've already had it and I'm mostly recovered now.

I was mostly asymptomatic. The biggest thing going on was that I was very tired, which was also something easily explained by other things going on, so I was basically already on the mend before I concluded I must have had it.

I believe we are barking up the wrong tree. We are looking for respiratory distress because it leads to low oxygen levels. I think we need to be looking more at what it does to the blood. Fortunately, some doctors are looking in that direction, but I think not enough, probably.

My symptoms were similar to anemia. It's easily missed because you mostly lack energy.

Again, there can be lots of reasons a person has low energy. It can be quite hard to say "Clearly, this symptom is indicative of Coronavirus."

So I suspect a lot of people will never be overtly symptomatic in the ways the world is looking for with its huge focus on lung issues.

nradov9• 6 years ago

Doctors are already seeing blood clots in many COVID-19 patients. Strokes, heart attacks, and pulmonary embolisms appear to be much more common than with other forms of viral pneumonia. Some hospitals have incorporated blood thinners into their treatment protocols.

lettergram• 6 years ago

People can test positive and are most contagious before they show symptoms. As opposed to influenza where people with symptoms are most contagious. The delay in the onset of symptoms is why this is a very difficult virus to contain.

Further, the accuracy of our tests is questionable and hopefully improving.

Finally, viral shedding has been seen up to 35+ days since symptom onset. Meaning if they showed symptoms a month ago, they may still test positive.

https://www.aarp.org/health/conditions-treatments/info-2020/...

pcdoodle• 6 years ago

Hope they didn't give them the batch that arstechnica reported contaminated.

nodesocket2• 6 years ago

Isn't this a bit of promising news, means herd immunity is probably much deeper and larger than we are currently aware.

DanBC2• 6 years ago

WHO says we can't assume previous infection means future immunity.

https://www.who.int/news-room/commentaries/detail/immunity-p...

drstewart• 6 years ago

That doesn't mean it doesn't, it just means it isn't scientifically proven yet.

theferalrobot• 6 years ago

No-one is assuming - we are weighing evidence and there is far more evidence that it does provide at least some immunity than none - it seems oddly disingenuous of WHO to make statements like this because they know how it will be interpreted.

SpicyLemonZest16• 6 years ago

The WHO says that we can't assume someone is 100% guaranteed to be immune when they have antibodies. That's true, and it's an important flaw in the idea of immunity passports that they're tackling - you couldn't send people with immunity passports into quarantined nursing homes or allow them to attend potential superspreading events.

Herd immunity doesn't require perfect immunity or a 100% guarantee of it. No reasonable expert doubts that herd immunity is possible, although some argue it's too costly.

nodesocket2• 6 years ago

Not sure why I am getting downvoted, I guess covid-19 shaming is a thing. From what I've read people who appear to get it again is actually just a relapse of the original infection[1].

[1] https://thehill.com/changing-america/well-being/prevention-c...

badfrog2• 6 years ago

The key part of that press release is:

As of 24 April 2020, no study has evaluated whether the presence of antibodies to SARS-CoV-2 confers immunity to subsequent infection by this virus in humans.

The most likely thing is that it does mean immunity, but the WHO isn't going to say that without clear evidence.

TallGuyShort• 6 years ago

You can be reinfected. It sounds like there's already some evidence suggesting that reinfection is at least significantly less likely than initial infection.

esoterica• 6 years ago

NYC shows that you will end up with probably 0.3% or more of the population dead before you get herd immunity. 0.3% of the entire US population is 1 million people.

MikeAmelung• 6 years ago

How many of those overlap with the 3 million people that are going to die in the US this year anyway?

azakai2• 6 years ago

It doesn't appear to mention what type of test was done. Were they checking for current active infection, or for antibodies which would indicate if the person has ever been infected? (if the latter, they may have had symptoms back then)

ImaCake• 6 years ago

I am not willing to even consider these results until more details about testing are revealed. There has already been so much misinformation about testing and results that I am incredibly skeptical of any results now.

djsumdog7• 6 years ago

Same here. Is there any chance the viral load test is also testing positive for other coronaviruses that are not SARS-CoV-2? Because I can't find any information addressing that.

w3mmpp• 6 years ago

by throwaway888abc

Pretty funny, good enough for reuters but not for HN it seems...

Brendinooo• 6 years ago

I don't know a lot about the antibody tests. Is the novel coronavirus novel enough that they know exactly the kind they're testing? Is it a specific test for SARS-CoV-2?

FabHK4• 6 years ago

There are many antibody tests. The one I’ve read about (from the Charité in Berlin) was designed (or found) to also test positive for the “original” SARS, and for very closely related bat viruses (neither of which should present an issue when testing humans today), but not for other corona viruses (such as the common cold etc.).

That test has also very carefully been validated, with excellent sensitivity (=few false negatives) and specificity (=few false positives). Not sure all available tests have gone through quite so thorough validation.

maxerickson• 6 years ago

The Ohio prison system is probably testing for the presence of the SARS-CoV-2 virus, not antibodies. That testing is specific to the virus (the type of test can respond to multiple viruses, but being specific to the target is one of the design criteria).

An antibody test should also generally be well targeted.

_2d303• 6 years ago

I'd guess smoking rates are very high in prisons. It seems smokers (even former) are much better off than non-smokers.

hkeide2• 6 years ago

That's the opposite of everything I've read

frereubu3• 6 years ago

I think they're referring to this: https://www.theguardian.com/world/2020/apr/22/french-study-s...

The idea is that nicotine may lower your chances of infection, but once established I imagine that smoking will definitely reduce your chances of survival.

macromagnon• 6 years ago

Smoking weakens your heart and lungs (and probably doesn't help high blood pressure) so what makes you say that?

_2d303• 6 years ago

https://www.theguardian.com/world/2020/apr/22/french-study-s...

https://www.qeios.com/read/article/571

MrPatan5• 6 years ago

Does anybody know the false positive rate of the test?

Could this be an artifact of that plus low actual incidence like:

- False positive rate of 10%

- 100 tests

- 1 true positives. All with symptoms

- 9 false positives. All without symptoms (duh!)

Headline: "90% asymptomatic!"

Truth: "Shitty test procedure!"

Yes, yes, I know you know this. Do you think people doing tests and writing headlines know this?

What is the false positive rate?

hutzlibu• 6 years ago

" Do you think people doing tests know this?"

Probably.

" Do you think people writing headlines know this?"

Maybe, but unlikely that they care, if the result is a flashing headline.

FabHK4• 6 years ago

No, that can’t be the case here, because a shockingly large proportion of people tested positive according to the article. (Thus, either the false positives are negligible, or the test employed has a an astronomical false positive rate (bad specificity)).

MrPatan5• 6 years ago

You're right, they get a positive result for almost all the population!

Wait, does that pass the smell test? Do prisions become huge flu hotspots as well? The Diamond Princess outbreak didn't have that kind of numbers... What's more likely at this point, the numbers from the article or human error?

My respects to anybody trying to do actual science with this kind of data in this kind of situation...

cwillu2• 6 years ago

They started with the Marion Correctional Institution, which houses 2,500 prisoners in north central Ohio, many of them older with pre-existing health conditions. After testing 2,300 inmates for the coronavirus, they were shocked. Of the 2,028 who tested positive, close to 95% had no symptoms.

cwillu2• 6 years ago

The article almost seems to be making a point of not putting all the needed numbers together for any given population that they talk about though.

jfasi• 6 years ago

This is the relevant response. What the commenter is trying to imply is that the authors of this study are so staggeringly stupid that they overlooked the possibility of false positives when designing this experiment.

In reality, this test would need a false positive rate of over eighty percent to explain this kind of asymptomatic infection rate.

Also, prisons are useful because due to the close quarters it can be taken as a given that a substantial proportion of the population is infected, further minimizing the danger of these sorts of errors. The choice of population suggests a sophisticated experiment design, and the commenter is implying that the study authors made a statistics 101-level error.

DoreenMichele4• 6 years ago

It's a prison population. Prisons and nursing homes are both seeing shockingly high infection rates because of the nature of what they do, which involves confining groups of people in close quarters.

People in nursing homes are elderly. Lots are dying.

People in prison aren't uniformly elderly. You are bound to see more variation in symptoms.

(Plus, as stated elsewhere, the opinions and experiences of known criminals tend to get discounted, so the report of lack of symptoms may be more about that than about the general resilience of the population. Also also: It's well established that if you ignore, dismiss and neglect someone enough, they stop complaining because they know it doesn't do any good. Aka learned helplessness.)

standardUser2• 6 years ago

Wild speculation is not the solution to lack of information. We all want to know how reliable these tests are. I don't understand why we can't find this information. But that is not an excuse to make nonsense assumptions and craft imaginary narratives.

IAmEveryone• 6 years ago

Plugging the 96% into New York numbers results in 155,000 / 4 * 100 = 3,875,000 infected people in NYC, or about half the population.

This is assuming that tests in NYC currently include every infected and symptomatic person. Considering the official advice for people with mild symptoms is to stay home (and not seek a test), that assumption is ... optimistic.

It also wouldn't fit with the anti-body tests that have been done in NYC that showed figures closer to 15-20%.

So I'd expect about 1/2 to 2/3 of these 96% to develop symptoms within the next week.

The other possibility is the prison population not being representative of the general population. That's probably true in terms of fatality rates, because they are younger. I'm not entirely sure if that age imbalance is just as strong for any symptoms as it is for risk of hospitalisation and death.

ivanhoe• 6 years ago

I've read that asymptomatic carriers are though to be less infectious than those with symptoms because of the lower concentration of virus in the saliva. Also, many virologists mentioned in recent texts that the initial concentration of the virus you receive can affect how sick you'll get - the more viruses you're exposed to, the faster they can invade the body and the more severe it will get.

Can those two facts be combined into a theory that asymptomatic carriers are more likely to produce more mild and asymptomatic cases?

Don't know if it makes any sense (probably not), but it would certainly explain how in some closed environments there's a prevalence for mild cases, while in others there's a plenty of very sick people, regardless of the age.

toshk3• 6 years ago

These were exactly the assumptions of the RIVM in the Netherlands end Februari and March causing it to completely spiral out of control.

johnchristopher• 6 years ago

Rijksinstituut voor Volksgezondheid en Milieu
Netherlands National Institute for Public Health and the Environment
The Netherlands National Institute for Public Health and the Environment, is a Dutch research institute that is an independent agency of the Dutch Ministry of Health, Welfare and Sport. RIVM performs tasks to promote public health and a safe living environment by conducting research and collecting knowledge worldwide.

Peter-Jan• 6 years ago

causing it to completely spiral out of control.

I live in the Netherlands and I think you could say that we actually have it quite under control (relatively speaking of course). We never reached peak ICU capacity and the ICU occupancy has been steadily declining for more than two weeks now[1]. Our schools for children between the ages of 4 and 12 are scheduled to partially open again on the 11th of may[2].

[1] https://nos.nl/artikel/2331720-coronacijfers-van-25-april-ri...

[2] https://nos.nl/artikel/2331460-kabinet-wil-basisscholen-voor...

ck2• 6 years ago

how do you ever make antibodies if you are perpetually asymptomatic though?

do you carry it forever? does it attack eventually?

what happens if you are an asymptomatic carrier and get a vax?

darkwater• 6 years ago

AFAIK asymptomatic means you show no symptoms but your body fights and creates antibodies just the same. Disclaimer: I'm not a doctor.

venning3• 6 years ago

"Typhoid Mary" was an asymptomatic carrier of typhoid fever for at least 38 years.

https://en.wikipedia.org/wiki/Mary_Mallon

jbritton• 6 years ago

I have been wondering about the effect of the degree of initial infection. I kind of assume the virus grows exponentially inside the body and would dwarf the initial constant. If a low initial dose affects the severity of the disease, I think that would be incredibly useful to know. I also wish there was info on percentage of infection via fomites vs inhalation.

fermienrico3• 6 years ago

I think it’s the opposite. The initial conditions have a profound effect on the exponential nature of the growth. Half the dose could mean that your immune system can suppress it. There is probably critical rate at which both growth rates match.

mgummelt• 6 years ago

I kind of assume the virus grows exponentially inside the body and would dwarf the initial constant.

Perhaps a more mild initial growth stage gives the immune system more time to respond.

vanniv6• 6 years ago

Early on, there was some discussion of the possibility that folks whose initial exposure is via the eyes would have a more mild illness than if the exposure was via nostrils or inhalation, because the immune system would have time to begin work while the virus was multiplying more slowly in tissue less suited to it.

I haven't heard anything in weeks studying anything like this, though, so I don't know where we ended up, if, indeed anybody knows anything at all.

tarsinge• 6 years ago

Not expert but I think if the initial constant can be several orders of magnitude different (I guess a few when airborne vs billions in a droplet) then it can impact the delay of the infection and give time for the immune response.

BurningFrog2• 6 years ago

Yeah, as I understand it, typically the "dose" of the initial infection is important for how bad the symptoms will be.

The virus will grow exponentially, but so will the immune response, so starting conditions are important.

This is a basis for the old pre vaccine "variolation" strategy of getting immunity. Some radical thinkers argue for it as a Covid remedy.

vikramkr3• 6 years ago

Most infectious diseases are dose dependent in their effects actually, which can be a bit counterintuitive. I dont know of any data for covid yet, but heres a paper on influenza, another viral disease:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4342672/

abandonliberty• 6 years ago

In addition to the other comments, there's also thought to be differing impacts by infection location.

Covid in your alveoli is very bad. Covid in your throat not so much.

jungletime• 6 years ago

Variolation

"The procedure was most commonly carried out by inserting/rubbing powdered smallpox scabs or fluid from pustules into superficial scratches made in the skin. The patient would develop pustules identical to those caused by naturally occurring smallpox, usually producing a less severe disease than naturally acquired smallpox. "

https://en.wikipedia.org/wiki/Variolation

ddebernardy• 6 years ago

I kind of assume the virus grows exponentially inside the body and would dwarf the initial constant.

That assumes your immune system wouldn't kick in during the asymptomatic phase or a time close to exiting the latter. But your immune system would actually kick in as soon as it detects the infection, which would plausibly be much earlier. That would effectively buying you time to figure out which antibodies to produce before things become out of control.

djsumdog7• 6 years ago

I remember one of the health experts in a Sam Harris podcast saying in an interview the dosage affects the severity and that this is seen in some other viruses (though I don't recall which ones). That's one reason doctors and nurses might be getting hit so hard, due to the continual exposure.

frereubu3• 6 years ago

Where did you read that? Superficially that might make sense - less virus particles == less obvious symptoms - but there are a wide variety of virus responses that show virulence and infectiousness aren't necessarily correlated.

If anyone wants to read more about this I can't recommend highly enough the book Spillover by David Quammen, which was published in 2012, and covers zoonotic (animal-to-human transmission) viruses, including SARS. Reading the section on SARS made the hairs on the back of my neck stand up. It's uncannily similar to what's happening with Covid-19, and explains a lot of the background involved in these kinds of viruses.

ketzo• 6 years ago

I actually do remember reading that this was true specifically in the case of COVID — that more exposure so far seems to correlate with a worse infection.

Sadly, I have no idea where I read this. But... I know I did! Recently! Maybe NYT?

netcan• 6 years ago

Bucheight

belltaco• 6 years ago

https://www.cebm.net/covid-19/sars-cov-2-viral-load-and-the-...

throwaway76142• 6 years ago

https://www.newscientist.com/article/2238819-does-a-high-vir...

alkonaut3• 6 years ago

A crude mathematical model from Swedish authorities on the Stockholm outbreak used two parameters: 1: the fraction of undetected cases (assumed to be mild or asymptomatic) and 2: the relative infectiousness of that group compared to the “detected” group.

The larger the undetected group is, the lower their relative infectiousness has to be in order to fit the observations. The best fit I believe was 1/25 detected and 11% infectiousness of the undetected group.

sandworm1012• 6 years ago

> Also, many virologists mentioned in recent texts that the initial concentration of the virus you receive can affect how sick you'll get - the more viruses you're exposed to, the faster they can invade the body and the more severe it will get.

That is basic infections 101. When you are exposed to any dangerous virus a race starts between the virus and your immune system. If the virus starts out only infecting a handful of cells, your immune system has a head start in developing antibodies before symptomatic infection sets in. (This is also a basic principle behind many vaccines.) But if you are hit will a massive viral load that instantly infects every cell in your lungs, the immune system is fighting uphill from day one. A massive initial viral exposure can also trigger an excessive immune response, for instance dangerously high fever. Such an immune response can be as deadly as the virus. Much covid research is going into not defeating the virus directly but regulating/slowing the immune response to the patient survives their own immune response.

This principal explains why healthcare workers are suffering so. They are exposed to constant massive doses of virus, possibly from multiple patients carrying slight different versions of the virus. So they get sicker than people who are exposed in the general community.

throwaway76142• 6 years ago

Sleep deprivation and extreme stress could be factors that affect healthcare workers (1)

https://theconversation.com/coronavirus-does-the-amount-of-v...

dima_medvedev• 6 years ago

There's already a comment above pointing out that it might be the initial infection location plays big role. Seems very likely that poor ventilation (in e.g. medical facilities) is main cause of severe cases.

Also, the virus is replicating exponentially only if it can reach many uninfected cells. It takes ~10 hours for an infected cell to start producing virus. Not sure whether non-specific immune system can somehow "contain" virus, would be great to learn about that.

Symmetry8• 6 years ago

It depends. If you're not going to develop symptoms for another 14 days then yeah, you're not infectious. But for a few days before symptom onset you become just as infectious as you will be after symptom onset - which is one of the things that makes this virus hard to stop.

A low initial dose doesn't seem to affect the course of the infection much, though. For a sufficiently low dose either none of the viruses find an ACE2 receptor or your innate immune system wipes up the virus without you noticing (as it does for you with other viruses every day).

There's some evidence that particularly high doses can cause particularly bad prognoses. We have pretty good evidence that this is the case with measles. There's very anecdotal evidence suggesting that maybe this is the case with SARS-CoV-2. But it looks like low doses lead to a chance of no infection, not a chance of an asymptomatic one.

greedo14• 6 years ago

I'm very confused by this as I understand that asymptomatic patients are infectious. How does this square with your second sentence?

SilasX• 6 years ago

I remember Robin Hanson [1] used the second fact to recommend "variolation", injecting everyone with a tiny amount of the virus so that they'll get the immunity without the sickness (making it a "natural vaccine").

[1] http://www.overcomingbias.com/2020/03/variolation-may-cut-co...

jedimastert• 6 years ago

I would think they'd be less infectious simply because they don't have symptoms that make them more so, namely coughing and sneezing and the like.

heisenbit• 6 years ago

Prof. Dr. Drosten (inventor of Covid-19 test) said in the interview below that there is a study which shows asymptomatic adult shed as much virus as symptomatic ones. He also said there is no good study on how many viruses are shed by kids.

https://tvthek.orf.at/profile/Additional-Content/1670/Langfa...

FabHK4• 6 years ago

Would be nice if they had specified what test (PCR from throat swap, from sputum, from stool; antibody test; …).

eblah• 6 years ago

Does anyone know if there's been any studies on those who have taken no medications at all in past X days vs those that take any (either OTC or otherwise) and those with and without symptoms?

I ask because I'd assume drug use would be lower in prisons, and among those in poorer countries. I'm just wondering if a particular set of drugs could accelerate/make this worse?

That said, I'm not sure this is even possible to obtain metrics on, it'd just be interesting to see if there's any type of correlation to rule out. I realize there's been conflicting studies on whether certain heart meds may accelerate, but I've not been able to find anything about any drugs use whatsoever.

colmvp• 6 years ago

As a Canadian, I'm shaking my head at our officials who said "we do know that asymptomatic people are not the key driver of epidemics" as a response to concerns back in January of the potential for the virus to grow in our country via incoming travelers who came from hot spots and were not screened or forced to isolate if they expressed no symptoms.

Now our long term care facilities are being overrun with cases potentially because we waited until deaths piled up before testing asymptomatic caretakers for the virus.

hazeii• 6 years ago

There's asymptomatic and presymptomatic (a very rapid spread could give lots of positive results before symptoms appear).

SlowRobotAhead4• 6 years ago

So, in two weeks, if these prisons are still 96% asymptomatic - then what?

I hope that’s the case, everyone should. I have yet to see a single indication this is worse than than anyone’s projections. I think that’s a dangerous scenario for the next time a virus comes along.

If there is any perceptionat all of overreacting, it’ll be a cry-wolf scenario with a lot of people.

tempestn2• 6 years ago

Agreed 100%. Here in BC, public health wasn't even saying, "It's not known whether asymptomatic carriers can spread the virus," but actually, "Evidence suggests asymptomatic carriers can not spread the virus." Something that as far as I can tell was never actually true. This was reported in public briefings, was repeated by public health nurses on the call-in lines, and was distributed as the government's official position to daycare workers, presumably among others. Really mind-boggling to me. I can only assume somewhere along the line lack of evidence got confused for evidence of lack, and just kept getting parroted from there.

antonvs• 6 years ago

"Evidence suggests asymptomatic carriers can not spread the virus."

I don't understand this. How would that even work? If you're infected, what would stop you from shedding virus like anyone else? Is there a precedent for this, for respiratory viruses?

uvesten• 6 years ago

Exactly like in Sweden. Our ministry of health has _almost_ given up the claim that asymptomatic carriers don't spread the virus by now, so... Progress!

prox• 6 years ago

Its the same story in Wuhan, probably quite a few asymptomatic carriers until the death toll start rising because of the exponential growth and came on the radar.

hn_check• 6 years ago

A test is a snapshot of time. A person could pass a test and be shedding viruses two days later. A person could shed viruses, get over it, and pass a test.

aazaa• 6 years ago

No mention of what kind of test was performed. And this article is not alone - most don't bother.

The kind of test matters. A qPCR tests the presence of an active infection. Antibody test determines past exposure.

Each has different expectations for symptoms, communicability, and prognosis.

It's not a lot to ask - just report the kind of test that was done, and do so with in the first two paragraphs. Then let me draw my own conclusions about what the study means.

That's a minimum. Ideally, an article would mention the exact brand of test that was performed. If heterogeneous testing methods were used, report that as well.

shawnz• 6 years ago

If it were an antibody test then I don't think it would be correct to say that they "tested positive for coronavirus", and also it wouldn't make sense to talk about their symptomaticity

JoeAltmaier5• 6 years ago

Lets not get too excited about this. Whatever the numbers, that's interesting and worth recording for planning. But whatever they are, they result in "way too many deaths". This is still a very dangerous and rapidly-spreading virus.

partiallypro• 6 years ago

I think the hope is that we could be closer to herd immunity than we think.

the8472• 6 years ago

Any herd immunity scenario is conditionnal on immunity is long-lasting, which is far from certain considering related viruses are recurring seasonally or in single-digit year intervals.

Don't bet the farm on it.

k2enemy• 6 years ago

Where is the cutoff between "way too many deaths" and not too many deaths? I don't mean to be glib, but it is an important question that needs to be weighed against destroying all of our economic institutions.

pgsbathhouse22• 6 years ago

that needs to be weighed against destroying all of our economic institutions.

No it doesn't. Like the statement alone doesn't even have any credence, let alone following through with it.

Incredibly daft.

JoeAltmaier5• 6 years ago

Strawman. Weigh it against suspension of economic institutions, new rules to mitigate the damage, and new institutions that operate on more rational basis.

tempestn2• 6 years ago

Yeah, one leap I often see made is, say a study shows "only" a 0.5% case fatality rate, about 5x as bad as an average flu. It's natural from there to then think letting it run unchecked would only be about 5x as bad as a flu. Very bad, certainly, but perhaps manageable. But that ignores the fact that there is a flu vaccine, and even without one the natural rate of spread of the flu is lower than this virus. So without measures, many more people would be infected and so it would be much worse than 5x an average flu, even if the CFR is indeed 0.5% (for example).

Of course, that doesn't mean these numbers aren't useful for planning and determining what degree of intervention is warranted, as you say.

Edit: could one of those down-voting explain? If I'm making a mistake here I'd like to understand it.

H8crilA• 6 years ago

This is actually not such a bad thing. It means that the true case rate is much much higher, and thus the true fatality rate is much much lower.

JoeAltmaier5• 6 years ago

The total fatalities are still unsupportably high. The #1 cause of death in the US, and its been around just a month or two.

The rates are interesting data. But don't make the leap to "not dangerously infectious"

finolex12• 6 years ago

A disease where only symptomatic people tend to be infectious would be far easier to manage and cause lower total damage even if it were deadlier.

spikels• 6 years ago

On the other hand this means it is much more infectious and there are many more infective asymptotic carriers. This will almost certainly make it impossible to contain using traditional public health means such as contact tracing and quarantining.

ilamont2• 6 years ago

96% are without symptoms yet.

There was a nursing home in Massachusetts which had 51 out of 98 residents testing positive but asymptomatic in early April. While this sounded encouraging in the sense no one was critically ill because of coronavirus, a few weeks later 19 had died and about 30 more had tested positive.

Let’s wait a month until there is a clearer picture about the impact of the virus on a particular population of people.

https://www.boston.com/news/local-news/2020/04/04/coronaviru...

https://www.wcvb.com/article/85-of-patients-at-wilmington-ma...

kfrzcode• 6 years ago

Is it indicated how long ago these inmates were tested? Seems like that's a key component in this mystery and I can't find it.

sharken8• 6 years ago

In Marion Correctional Institution, Ohio it could look like the tests were conducted in mid-april according to https://drc.ohio.gov/Portals/0/DRC%20COVID-19%20Information%....

But as of 25-04-2020 at least 4 inmates have died to Corona virus according to https://eu.marionstar.com/story/news/local/2020/04/24/corona.... There are 2,564 inmates (https://drc.ohio.gov/mci).

JPKab• 6 years ago

Did you see the NYC antibody sample that showed that approximately 21 percent of citizens had antibodies? It seems like a nursing home is a pretty bad representation of a population.

ilamont2• 6 years ago

I agree, but so is a group of male inmates (many of them older) compared to the general population. Until more testing on this group is done in a few weeks and symptoms emerge, we won’t have a clear picture on how many are truly asymptomatic.

prussian• 6 years ago

Am I the only one who is still confused by what they're finding in these antibody tests? Are they looking for antibodies that attach to specific features unique to SARS-CoV-2? Because I'm pretty sure even HCoV-NL63 enter lung cells through ACE2 as well. How can they tell antibodies for these viruses apart? Also aren't antibodies effectively developed in a sort of random process?

jpster• 6 years ago

I am not sure how reliable these studies are, given this reporting:

https://www.nytimes.com/2020/04/24/health/coronavirus-antibo...

bashtoni• 6 years ago

It didn't show that - there's a good analysis at https://towardsdatascience.com/were-21-of-new-york-city-resi...

pbourke• 6 years ago

I don’t buy any inference drawn from that study that is in the realm of “20% of the population of NYC was exposed to SARS-CoV-2 and developed immunity”

I think that will be the primary message that people will get from that study.

AJ007• 6 years ago

8,399,000 people in NYC, 21 percent of that is 1,763,790. 1% of that is 17,000.

So far as of Saturday at 6:49pm EST 16,919 have officially died in NYC.

I think the anti-body test in this case is fairly close and the death rate is probably 1% more or less depending on the demographic distribution. Obviously there are a number of people in NYC who will die over the next month even if all new infections where halted right now.

The serology tests are just wrong when only a small number of people in the sample were infected, which is what we’ve seen from the stuff in CA so far.

hristov• 6 years ago

I am not sure that these antibody tests mean what people generally think they mean. For example, there seem to be multiple events where people get sick even after it has been established that they have antibodies.

Furthermore, people in environments with a lot of virus (i.e., cruise ships, hospitals, or just northern italian towns where the virus has run amok, tend to get sick and die at much higher rate than those antibody tests would suggest.

There may be a mechanism for multiple infection which makes multiple exposure more dangerous even if you have antibodies.

RangerScience2• 6 years ago

...Let's also ask if the tests have a high false positive rate?

bumby6• 6 years ago

Dr. David Katz was just in Bill Maher’s show indicating the test has a high false negative rate

usrusr• 6 years ago

Even more relevant to this observation is that false positives aren't properly random: if the test happens to be falsely positive for some other rare virus it's very much possible that the entire prison was hit by that virus, creating a cluster of connected false positives.

not_a_moth2• 6 years ago

? You're comparing a prison to a nursing home

Another data point, ~12k healthy foreign workers in Singapore have tested positive. The city-state has only 12 deaths total (all elderly, not the foreign workers). In Singapore the foreign workers may have already been asymptomatic for weeks.

Based on NYC data, LA city data, Stanford's Santa Clara data, Singapore, Danish blood donor data, a picture is emerging that the virus is not particularly dangerous to healthy people.

pavlov• 6 years ago

Prisoners in America are not in great health. Many untreated conditions, often inadequate health care since birth.

wonnage2• 6 years ago

1. Most of these cases were diagnosed in the last two weeks

2. Over 5000 (roughly 40%) have been hospitalized https://www.scmp.com/week-asia/health-environment/article/30...

Data from antibody tests can so far be summarized as garbage:

- https://www.buzzfeednews.com/article/stephaniemlee/coronavir...

- https://statmodeling.stat.columbia.edu/2020/04/19/fatal-flaw...

I guess the TL;DR of all of this is, this picture you're talking about is a fallacy premised on bad data

covidSurvivor192• 6 years ago

Want to make a bet they won't develop symptoms? Or at least please help me understand how can you compare these two populations with wildly different average ages, preexisting conditions, etc...

arcticbull14• 6 years ago

The virus affects young and healthy folks without co-morbidities dramatically less than it does old folks at a nursing home. Based on New York City data, people without co-morbidities account for something like 6% of hospitalizations [1]. Old folks on a cruise ship full of old people, about 20% showed no symptoms. Is it a big stretch to think that scales to prisoners as shown? They're pretty young (only 2.8% of prisoners are over 65 [2]), and therefore pretty unlikely to show symptoms let alone require medical care. Age is unquestionably the biggest factor in outcomes for COVID [3].

"Asymptomatic" is kind of a sliding scale. Are you sick? No. Do you have a stuffy nose? Kinda.

[1] https://www.the-scientist.com/news-opinion/nearly-all-nyc-ar...

[2] https://www.bop.gov/about/statistics/statistics_inmate_age.j...

[3] https://www.cdc.gov/mmwr/volumes/69/wr/mm6915e3.htm

pastablister2• 6 years ago

Perfect, sounds like a good experiment then, so let's wait and see.

Bnshsysjab2• 6 years ago

Wouldn’t prisons disproportionately have poorer health than average for several reasons?

ancientworldnow• 6 years ago

Over 40% of Americans have comorbidities (hypertension and obesity being most common) so that stat is not particularly useful.

superkuh• 6 years ago

If a virus is spreading in a community exponentially and the latency from exposure/infection to symptoms is greater in length than the doubling time then half of everyone who tests positive is going to be pre-symptomatic.

pastablister2• 6 years ago

Is this not just another Diamond Princess Cruise?

emiliovesprini• 6 years ago

Also there have been reports of Ground Glass Opacities[1] in the lungs of people with infections previously thought of as asymptomatic.

[1] https://en.m.wikipedia.org/wiki/Ground-glass_opacity

arcticbull14• 6 years ago

Sure, but that doesn't mean they... won't go away. In fact, I'm pretty confident all signs point to the fact they will go away. In fact you get ground glass opacities with H1N1 inflenza [1]. I guess the question is "functional asymptomaticity" vs "actual asymptomaticity". Like, if it's not bad enough for people to even notice does it really matter?

[1] https://pubs.rsna.org/doi/full/10.1148/radiol.10092240

sandworm1012• 6 years ago

Fine non-Covid point:

>> The United States has more people behind bars than any other nation, a total incarcerated population of nearly 2.3 million as of 2017 — nearly half of which is in state prisons. Smaller numbers are locked in federal prisons and local jails, which typically hold people for relatively short periods as they await trial.

That isn't correct. "Local Jails" hold two general populations: people serving less than a year (generally non-felony convictions) and people awaiting legal process. The infamous Rikers Island in NY is technically a "local jail". People regularly stay in these facilities for YEARS. The AVERAGE stay at Rikers is 6+ months. (Total stay, not time between appearances.)

The distinction between "jail" and "prison" in the US is academic. For purposes of disease, and certainly from the perspective of inmates, both are prisons where large populations are locked up in confined quarters for years at a time.

sergiotapia• 6 years ago

“It adds to the understanding that we have a severe undercount of cases in the U.S.,” said Dr. Leana Wen,

There it is! Now can we get back to normal. Of those 4% with symptoms, what tiny percentage need advanced hospitalization? Of that tiny percentage, what tinier percentage still, die?

robocat2• 6 years ago

If the virus moves fast through a population (like we might expect in a crowded prison) then all the population in one provision will have a single strain.

However, this is 4 prisons: do staff or inmates move between prisons more often than say every week?

It is possible (although unlikely) the virus strain is less spdangerous.

jwlake• 6 years ago

One of the super-interesting things here, is that apparently everyone was in the specific window where they test positive for the virus. This implies the population was recently infected, had not been previously infected, and it spread almost completely within a tight window.

This implies a shocking high R(effective) for that population. In 2 weeks we'll have super interesting data one way of the other on the CFR.

Retric4• 6 years ago

Covid-19 fatalities takes up to 2 months after infection, symptoms have a median of just over 5 days from first exposure.

hartator• 6 years ago

Median of 10 days though.

not_a_moth2• 6 years ago

Only if you develop a severe case in the first place, which you would know about within 2 weeks average. Incubation on average is 3-5 days, severe symptoms then start in the second week.

After you're hospitalized, yes you might or might not then have a month long battle for survival.

GuB-424• 6 years ago

Keyword "up to".

The most common fatal case seems to be roughly: 1 week without symptoms, 1 week of mild symptoms, 1 week of severe symptoms, death. That's 3 weeks.

In rare (1/10000) cases, incubation time can reach 14 days, that's where the 14 days quarantine recommendation comes from. But the median is closer to 5 days.

Time to death can be much longer, the virus can cause all sorts of damage to the body, including secondary infections. And if the patient is strong enough to resist the primary infection but not enough to recover, it can take a long time.

MrPatan5• 6 years ago

Exactly! What are the chances of that, compared to a gross error in the testing, like someone processing the samples was infected and not very careful?

gridlockd5• 6 years ago

The chances of an antibody test kit not being sufficiently specific to SARS-CoV2 as opposed to endemic coronaviruses is quite high.

Now, what are the chances that some government institution acquired tons of crappy test kits, didn't validate them before use, and then proceeded to publish the results which just so happened to be exactly what they wanted them to be?

Symmetry8• 6 years ago

SARS, MERS, and now SARS-2 are all known for super-spreader events where occasionally one person just infects a ton of other people. And we know from testing that the amount of live virus in a person's phlegm can vary by many orders of magnitude so I guess that isn't surprising. There are a lot of people who infect just one other person but the overall R(effective) is substantially driven by the long tail.

Gibbon1• 6 years ago

I repeatedly point this out. There was the church choir practice where 45 out of 60 people were infected within what two hours? There is also a Korean call center where about 2/3 of the people in an open office were infected.

I've repeatedly linked to CDC study that estimates r0 in Wuhan before lockdown at between 3.8 and 8.7. Median 5.8.

Take away: Completely avoid being indoors with large groups of people.

suzzer993• 6 years ago

Especially if they're singing or talking non-stop.

gridlockd5• 6 years ago

That's also shown in the recent outbreak in Singapore - almost all of the cases are migrant workers housed in tightly packed dormitories.

danieltillett7• 6 years ago

A prison is very much like a cruise ship from a viral perspective. We know from the cruise ship data like the Diamond Princess that most people had no symptoms initially, but overtime most people became symptomatic [1].

Of course if we are really lucky and the prison was infected with a naturally attenuated strain we should make use of it [2].

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7078829/

2. https://www.tillett.info/2020/04/12/how-would-a-search-for-a...

cameldrv• 6 years ago

I think that. depending on the air conditioning system, it might be quite a bit worse. The density of people is huge, air flows freely between cells, prisoners eat packed together at communal tables. I bet R is like 10-20.

lyjackal• 6 years ago

Prison demographics are very different than cruise ships, so might be interesting if different

Fjolsvith3• 6 years ago

A prison is very much like a cruise ship from a viral perspective.

Prisons are much worse. Chow line with men almost heel to toe. Commissary line. Med line. Recycled air. Big crowds in small spaces.

justnotworthit• 6 years ago

We know from the cruise ship data like the Diamond Princess that most people had no symptoms initially, but overtime most people became symptomatic [1].

Your wording is too strong. Data is 50% asymptomatic at time of testing, paper models that that number dropped to 20%.

from paper on 19 February and 50.5% (320/634) on 20 February (Table). Soon after identification of the first infections, both symptomatic and asymptomatic cases were transported to designated medical facilities specialised in infectious diseases in Japan. However, these patients were treated as external (imported) cases, and a detailed description of their clinical progression is not publicly available.

We conducted statistical modelling to derive the delay-adjusted asymptomatic proportion of infections, along with the infections’ timeline. The estimated asymptomatic proportion was 17.9% (95% credible interval (CrI): 15.5–20.2%).

bshanks2• 6 years ago

Since the hospitalization and mortality rates vary so much with age, it would be surprising if the rate of asymptomatic cases didn't. Since prisons skew young we would expect a much higher proportion of asymptomatics to be found there than in the general population.

darkerside3• 6 years ago

I'm looking for this in the article and not seeing mention of a specific window. Can you help me find what you're referring to?

icegreentea22• 6 years ago

The sensitivity of PCR tests to SAR-COV-2 varies over time from time to infection. I think the the OP is overestimating how narrow this window is though. It's not like you need to test within a few days or a week to be positive - it's just that viral load is maximum for only a few days (roughly the +/-3 days around onset of symptoms).

Even after the viral load in the upper respiratory tract drops off, there's still lots of virus around. You'll likely test positive -1/+2 weeks around onset of symptoms.

mynegation• 6 years ago

Do not know if it is in the article or not but I guess the reasoning from GP goes like this: huge percentage of people are pre-symptomatic. The median time for symptoms to appear is 4-5 days from infection time, so they were probably infected in a very short period of time recently.

laufj2• 6 years ago

We don't know if infection provides immunity, so they could be repeat infections, or even viruses that never cleared.

adwi• 6 years ago

Why is this being downvoted?

Yesterday the World Health Organization said: "There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection."

https://www.npr.org/sections/coronavirus-live-updates/2020/0...

andrei_says_• 6 years ago

Are these tests covid-19 specific or are they based on IgM/IgG?

The results of the tests for IgG, IgA, and IgM levels are usually evaluated together. Abnormal test results typically indicate that there is something affecting the immune system and suggest the need for further testing. Immunoglobulins testing is not diagnostic but can be a strong indicator of a disease or condition. There are a number of conditions that are associated with increased and decreased immunoglobulins.

qznc• 6 years ago

We will also see if they are asymptomatic or presymptomatic.

misja111• 6 years ago

> .. that apparently everyone was in the specific window where they test positive for the virus.

The data comes from 4 prisons. It is theoretically possible that all 4 of them happened to be in the same window after an initial infection, but it doesn't seem very likely. I guess the only way to be sure is to do follow up tests every week or so, hopefully that will happen.

ineedasername4• 6 years ago

The CFR will be an interesting (though tragic) data point, but I wouldn't generalize too much from it. The demographics of the inmates are probably not representative, and the health care that prisoners receive is absolutely not of the same quality that civilians may receive.

The Princess cruise was a good indicator of CFR for a specific demographic range when they tested early, often, and had access to quality care. If the CFR of this prison will tell us anything, it will be a counterpoint to such information showing what happens when quality of care is greatly diminished.

8note2• 6 years ago

From what I can tell, this makes a strong suggestion that were much further through infecting the whole population than we think.

Anyone with some bayesian ideas on by how much?

crazygringo• 6 years ago

Every article I see about people testing asymptomatic is followed by comments insisting they were asymptomatic when tested, with no idea of whether they stayed asymptomatic or whether virtually all of them had symptoms a few days later, thus basically invalid.

But this doesn't seem like a hard problem to solve, folks. Is nobody bothering to follow up with the asymptomatic people a week later? Just take their mobile phone number, and text them en masse with a quick Y/N question as to whether or not they got sick?

This stuff baffles me. This is literally a matter of life-and-death, and yet the most basic questions seem to be unanswered. (Or are these follow-up surveys being done but the media just refuses to report them because it now feels like week-old news? I'd love to know.)

lukevdp• 6 years ago

Yes, one study when the diamond princess was tested it was originally 50% asymptomatic and then later on that had gone down to under 20%

graeme• 6 years ago

A lot of the asymptomatic cases had pneumonia in their lungs too. They were however still able to expel CO2 and so did’t feel shortness of breath.

wk_end3• 6 years ago

Someone else mentioned those numbers in a cousin thread but as far as we can tell there's no source for that. Do you happen to have one?

See the comment thread here https://news.ycombinator.com/item?id=22981423

nradov9• 6 years ago

The USS Theodore Roosevelt situation was discussed here several days ago. At this time about 60% of the crew who tested positive are still asymptomatic. Enough time has passed that we can be confident they aren't just presymptomatic. Numbers are pretty solid since they were all quarantined and tracked. Infection fatality rate was about 0.1%, however that's probably not representative of the general population.

edmundsauto6• 6 years ago

Also, how should we weight the validity of the data, given the political leadership issues surrounding this situation.

jdietrich• 6 years ago

Infection fatality rate was about 0.1%, however that's probably not representative of the general population.

That's something of an understatement - deployed naval personnel are almost exclusively young and healthy, putting them at exceptionally low risk of becoming seriously ill from COVID-19.

jariel• 6 years ago

It's truly disorienting.

We need good data, badly, and we have an entire world as our Petree dish and yet can't seem to get it.

You'd think the CDC would be sending out questionnaires, forms, coordinating such tests, giving guidelines, collating results etc..

Literally the worst economic shock maybe ever and we can't count marbles to save ourselves.

jacobush2• 6 years ago

CDC don’t seem to have permission to communicate with the public

pbhjpbhj9• 6 years ago

The CDC, AIUI, just advise medics and governments? It's up to the politicians to enable it - eg by putting medics in charge!?

azakai2• 6 years ago

The CDC is working on this, for example

https://www.statnews.com/2020/04/04/cdc-launches-studies-to-...

vosper• 6 years ago

Just take their mobile phone number, and text them en masse with a quick Y/N question as to whether or not they got sick?

I've been wondering why this isn't just being done for everyone in the country, every few days?

"The main symptoms of COVID-19 are X, Y, Z. If you think you may have COVID-19 please respond "Yes" to this text message. This is free. Your response is private and used to understand the spread of COVID-19 in our country. Please visit http://some.link for more information"

If someone responds "yes" you could follow up with some more questions, if that was useful. And then text them a few days later to see if they're feeling better or worse, or maybe ask them to describe how they feel.

There are lots of problems with this idea: people lying or not taking it seriously; people not responding; not everyone has a cellphone; some people will be worried about privacy, etc etc...

But surely there'd be something useful to learn from it? And it seems like it should be easy to do, really, if you got the mobile providers on board (or just order them to help).

alexis_fr• 6 years ago

Do you even need to be an official to do that? Perhaps a newspaper could do it, to accurate news.

CydeWeys9• 6 years ago

In Italy they're personally tracking every confirmed case. Meanwhile, here in NYC, I called 311 to report my suspected case and that wasn't even a thing they were tracking. We just don't have our shit together over here, not at a state or national level.

walterbell• 6 years ago

Vague and/or non-comparable data provides decision deniability and narrative flexibility in many possible futures. Open-source analysis and watchdogs provide one level of defense.

https://covidtracking.com/blog/weve-launched-a-new-state-gra...

We're rolling out a new, more rigorous system for grading the public health data each state reports.

thedrbrian• 6 years ago

In the uk at least we have an app that you can update with your current health status/feelings and they can track the Wuhan flu with that. They are encouraging users to report in once a day even if you have no symptoms.

https://apps.apple.com/gb/app/covid-symptom-tracker/id150352...

jackcosgrove2• 6 years ago

I recently completed a survey conducted by NORC which asked a series of questions that seemed to test whether I had contracted Covid-19. I received the survey invitation in the mail so it must have been randomized. We'll have to wait to see the results.

ShorsHammer2• 6 years ago

It is being done though, virtually everywhere. Huge amount of testing worldwide is confirming case recovery.

You are conflating armchair epidemiologists on HN with the reality on the ground. What people say here doesn't reflect what is being done.

standardUser2• 6 years ago

Where is the follow up data? Is there a link or reference? Or do you have inside information?

randyrand• 6 years ago

Do states have an legal obligation to prevent the spread of disease in prisons? It seems like prison does not provide enough space to stop people from dying from diseases.

I wonder if you can sue.

kgin• 6 years ago

Alone, this doesn't show anything. But following this population for 3 weeks should tell us a alot.

vrtx0• 6 years ago

I posted the following comment on a very similar Reuters article about asymptomatic rates on an aircraft carrier 8 days ago (on a Friday):

- - IMHO, this article is intentionally misleading. The incubation period is currently estimated to be 2-14 days (mean is 5.6 days per CDC, similar per WHO). The article doesn’t mention any dates or time frames, but does mention: ”Roughly 60 percent of the over 600 sailors who tested positive so far have not shown symptoms of COVID-19” — note how “so far” is ambiguous in that sentence. It also states, “The Navy’s testing of the entire 4,800-member crew of the aircraft carrier - which is about 94% complete...”, which seems to indicate nowhere near enough time has elapsed to draw any sort of conclusion. This paper [1] found that testing of all pregnancy patients in a hospital yielded 34% asymptomatic cases. That number drops to 8% “shortly after discharge”, and could be lower than 8% (Again, no timeframe is stated). [1] https://www.sciencedirect.com/science/article/pii/S258993332... - -

If you just s/navy/prisons/ and s/[navy figures]/[prison figures] (and forgive my oversimplification of RegEx captures), I think that comment works just as well here.

At the risk of sounding paranoid, does this seem like a campaign of misinformation by omission? Or perhaps I’m being overly critical?

The key issue I take with both articles is that they speculate a lot, but gloss over the fact that no timeframes are provided to determine what percentage could actually be asymptomatic and never develop symptoms vs. simply being pre-symptomatic at the time of testing.

If the article were focused on how quickly this virus can spread in closed quarters, that would be one thing. But this rather lengthy article only has one sentence in the middle that even mentions asymptomatic cases eventually developing symptoms:

“Some people diagnosed as asymptomatic when tested for the coronavirus, however, may go on to develop symptoms later, according to researchers.”

Also, this article mentions testing asymptomatic prisoners (universal testing), but it doesn’t say why these specific prisons where chosen first. Perhaps some had at least one positive test result? If so, wouldn’t the close quarters explain most of the relatively high rates of asymptomatic positives reported, given the (initially) exponential curve of spread over time?

codecamper• 6 years ago

I've read there are over 10,000 strains of the virus, some more deadly than others! https://www.scmp.com/news/china/science/article/3080771/coro...

Munky-Necan• 6 years ago

The cruise ships were a great Petri dish and so far it is believed that asymptomatic patients comprise 15-20%, but more research is needed.

https://www.niid.go.jp/niid/en/2019-ncov-e/9417-covid-dp-fe-...

BurningFrog2• 6 years ago

Two questions:

1. How good is this test? Maybe people have no symptoms because the test is wrong?

2. Is there some reason prisoners would deny having symptoms even if they did?

kensai• 6 years ago

Ioannidis was right all along.

konschubert• 6 years ago

One potential cause: We habe hints now (Charité Study) that previous infections with other, less harmful corona viruses may provide some degree of immunity (unconfirmed).

Maybe one or more these other coronaviruses made rounds in this prison earlier this year?

empath75• 6 years ago

The nature of exponential growth is such that no matter when you test, 50% will have gotten it within the last doubling period. If it’s doubling every three days, half have caught it in the last 3 days, 75% in the last 6 days, 86% in the last 9 and so on. Given the long incubation period it makes sense that the vast majority are currently asymptomatic. I think that will be the case at every point during exponential growth, even if the ultimates fatality rate is quite high.

covidSurvivor192• 6 years ago

At this point only thing I can ask is, forget the shutdowns, when we'll we recognize the most viral thing about COVID was the histeria? Having lived closely through the swine flu, it was quite a bit worse, affected people under 60 which tend to be more socially active and no shutdowns were required. In fact one of the learnings/facts of that crisis were that masks are mostly useless to prevent contagion.

briandear3• 6 years ago

The numbers are the latest evidence to suggest that people who are asymptomatic — contagious but not physically sick — may be driving the spread of the virus

That’s also suggesting that the fatality rate is nowhere near what we have been led to believe.

icebraining• 6 years ago

What have we been led to believe?

finolex12• 6 years ago

To add another data point, Singapore has been testing foreign workers living in dormitories extensively, uncovering about 10,000 cases (about 80% of the country's total cases). These are relatively fit individuals between the ages of 20 and 40. However, the number of people in the ICU has remained remarkably consistent at about ~20 people in the past 10 days (Fingers crossed it remains that way).

https://www.moh.gov.sg/news-highlights/details/46-more-cases...

reddothomme• 6 years ago

Many migrant workers in Singapore are the only breadwinners for their families back home in Bangladesh/India/Myanmar. One of the reasons the Singapore government has done extensive testing way beyond global standards is that many of these foreign workers are financially disincentivized to seek medical help the moment the first symptoms appear. The fact that Singapore's leader has publicly promised stable incomes for this affected group speaks volumes of the government.

As a fellow south east asian, I am deathly afraid of the under-reporting and testing in other ASEAN countries. Singapore. A 2017 statista study of migrant worker populations in South East Asia (https://www.statista.com/statistics/711513/asean-number-of-m...) shows that Malaysia and Thailand have much larger migrant worker populations than Singapore. Their living conditions are either on par or worse than the ones living in Singapore, yet there are apparently no Covid-19 clusters among migrant populations in other ASEAN countries. This is extremely alarming.

tim3332• 6 years ago

Thailand just yesterday reported some.

_-___________-_4• 6 years ago

It would be extremely alarming if there were large numbers of deaths or hospital admissions occurring among the Singapore workers who are testing positive. Given that there are virtually none, the lack of testing in other ASEAN countries is hardly extremely alarming. A lack of data is less concerning if you wouldn't do anything differently if you had the data.

leon1717• 6 years ago

Whether a conspiracy or a fuck-up, the more weaknesses of democracy exposed by this virus, the more benefits the survivals will have in the long run. DT be like:"Kill all those intouchables, so I'll have another 4 years sitting on the bloody throne!"

rsuelzer• 6 years ago

Are these antibody or antigen tests? I am extremely suspect that the antibody tests being used are not delivering false positives. There was a study that showed 800,000 people in Los Angeles likely have antibodies. This does not make sense given that the ICU admissions did not even remotely track that of Northern Italy, which shared a similar population size. I suspect that these antibody tests are picking up a positive on another another Coronavirus.

m3kw9• 6 years ago

Yet elsewhere, hospitals are flooded and body bags piled.

thatsenough• 6 years ago

Because people with the worst symptoms go to the hospital.

OrgNet2• 6 years ago

Georgia's actions don't seem so dumb now...

giardini• 6 years ago

The Reuters article is not useful. It doesn't tell us the type of tests being done, and certainly says nothing about false positives. Like most other articles, this article is what I call "bullshit" but John Ionnidis calls:

"Lies, Damned Lies, and Medical Science":

https://www.theatlantic.com/magazine/archive/2010/11/lies-da...

Dr. Ioannidis on Why We Don't Have Reliable Data Surrounding COVID-19:

https://www.youtube.com/watch?v=QUvWaxuurzQ&feature=emb_logo

djsumdog7• 6 years ago

I was doing stuff with the Johns Hopkins data and it has all kinds problems with it (not to mention the format is terrible; time series as columns?!). They also tacked on the retroactive New York cases to the end to the time series data. I did a post on it:

https://battlepenguin.com/tech/fighting-with-the-data/

puskavi• 6 years ago

Mutation or less harmful strain?

bouncycastle2• 6 years ago

Maybe the virus has evolved (through natural selection) to not to kill its hosts?

travbrack• 6 years ago

People who die from the virus usually infect many others before death. There isn't really any selection pressure for keeping the host alive.

bouncycastle2• 6 years ago

Sure, but people who don't show symptoms can infect more! So in that case, the less potent one becomes more dominant, no?

Meanwhile those who show symptoms are more likely to stop infecting as soon as they're isolated.

That said, I'm not sure if there has been any different stands identified yet?

luckydata• 6 years ago

96% asymptomatic FOR NOW. We’ll see later.

SlowRobotAhead4• 6 years ago

Will we though? Or more likely we’ll never hear about stats from these four state prisons again?

ageofwant• 6 years ago

An asymptomatic presentation would not include a chest x-ray. People with visible lung lesions and 60% oxygenation levels doe not exhibit any symptoms. The body's warning system is wired to C02 concentrations, and C02 gets evacuated so people report feeling fine while they have significant lung damage.

ping_pong• 6 years ago

Is there the possibility that these test results are wrong? The spread is far wider than what would be expected and that means that quarantining and contact tracing would be eseentially useless. But we've seen that both are very useful.

Ascetik• 6 years ago

Look up Dr. Andrew Kaufman on Youtube. Medicamentum Authenticam.

elihu• 6 years ago

Some possibilities: there is widespread infection from a common source around the same time, and many of those "asymptomatic" inmates aren't going to stay that way; the test has false positives; the population of this prison is comprised mostly of people who tend to be asymptomatic carriers (for example, if most prisoners are in their early 20's); COVID-19 has a lot more asymptomatic carriers than we thought.

greedo14• 6 years ago

It's 4 prisons. The odds of there being one Typhoid Mary is unlikely.

laufj2• 6 years ago

I'm curious how they determined if inmates were asymptomatic. If it was just asking, the symptoms may be under reported. In prison, you try and appear invincible, your survival depends on it, so I could imagine many people saying they are asymptomatic when they are not.

Meckin• 6 years ago

So many assumptions, I highly doubt from my time being in prisons others would think... Oh man that guy has the cold.. He must be weak.

atmosx• 6 years ago

Same thing happened in a Greek “hot spot”, a prison for refugees. These places were build to host X number of inmates but in reality they host close to 50X. The population were infected at nearly 100% without symptoms.

greendesk• 6 years ago

Are there differences in vaccination in the affected population? A noteable difference is the age group of high risk group is ~65 in Italy and ~80 in Sweden. (Citation needed, I only found secondary sources). These ages correspond to changes in vaccine regimen in the affected countries. Might the younger inmates have been vaccinated differently?

DeathArrow• 6 years ago

Is there a an explanation for why US has the highest prison population in the world?

gridlockd5• 6 years ago

With those kinds or positive rates, I have to start wondering about the specificity of those tests.

The UK government recently hat to gave up on millions of antibody tests because they just didn't work.

Coronaviruses in general are endemic and almost always go without symptoms and would also eventually spread to the majority of the prison population.

anticensor• 6 years ago

They should be conscripted to the war front with symptom-suppressing medication, to prevent further contamination of inmates.

unexaminedlife• 6 years ago

I'm curious to know exactly what the science is behind the tests being performed currently. And how does a body typically fight a virus in the first place?

This might sound amateurish (it is), but I have been picturing this virus and how our bodies are fighting it similar to how our bodies fight cancer. Tons of people who never end up with cancer diagnosis are constantly fighting off cancer cells, it's just that the capacity of their (relatively) healthy bodies exceeds the total # of cancer cells they need to fight off.

Is it possible these tests have become too sensitive to where they're easily detecting the virus in seemingly healthy people?

CryptoPunk5• 6 years ago

So it strikes me as possible that SARS-CoV-2 has a very high r value and lethality on par with flu viruses, but is killing a lot more people than flu viruses due to the lack of pre-existing immunity, combined with the rapid spread through the population claiming those most vulnerable to it all at once.

freeflight2• 6 years ago

One of the more interesting differences between US prison populations and others is that smoking tobacco is way more prevalent:

Estimated smoking prevalence among inmates was approximately 50% in 2003–2004, compared to 21% among noninstitutionalized adults. [0]

Which might play a major role in the spread and the actual severity of COVID-19 as French researchers are speculating that nicotine could be responsible for blocking the ACE2 receptors that COVID-19 uses to get into cells, which could explain why there's such a low incidence of tobacco smokers among patients, far below what should be expected [1].

There's nothing really concrete yet, for now they want to experiment with nicotine patches as treatment.

But in that context, prison populations could make for an interesting control group: Maybe the prevalence of smoking is what keeps the virus less severe, due to reduced viral load reaching cells, and thus fewer carriers are symptomatic?

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5100810/

[1] https://www.qeios.com/read/article/574

acconrad• 6 years ago

I could see this making sense for tobacco users that don't smoke (e.g. chewing tobacco) but for people that smoke...I mean this is a respiratory illness. If you have compromised lungs this seems like it would be a nightmare for smokers. Are you concerned at all with the veracity of these claims?

freeflight2• 6 years ago

Not at all, I'm merely sharing information that might be interesting to this situation.

Nowhere did I declare anything as fact, I even called something "speculation" by researchers when they don't consider it much one themselves:

There are however, sufficient scientific data to suggest that smoking protection is likely to be mediated by nicotine. SARS-CoV2 is known to use the angiotensin converting enzyme 2 (ACE2) receptor for cell entry[14-16], and there is evidence that nicotine modulates ACE2 expression[17]which could in turn modulate the nicotinic acetyl choline receptor (manuscript submitted). We hypothesize that SARS-CoV2 might alter the control of the nicotine receptor by acetylcholine. This hypothesis may also explain why previous studies have found an association between smoking and Covid-19 severity[1, 9, 10]. As hospitals generally impose smoking cessation and nicotine withdrawal at the time of hospitalization, tobacco (nicotine) cessation could lead to the release of nicotine receptors, that are increased in smokers, and to a “rebound effect” responsible for the worsening of disease observed in hospitalized smokers.

In that context, it really doesn't matter if this is a "respiratory illness", as nicotine can be applied in a number of ways, like patches.

So even tho it might seem counter-intuitive, this could be part of a plausible explanation why smokers are so underrepresented among COVID-19 patients not just in France, but also in the US and China.

danpalmer• 6 years ago

On the other hand, in China they saw more susceptibility in men, which many have thought could be related to the cultural norm for men to smoke (and women not to).

Jemm• 6 years ago

Reuter’s website is a shit show of moving popping, sliding gizmos. Makes it unreadable. I can’t imagine using a screen reader with that.

It is like constantly rearranging the furniture while a blind person is in the store.

barli• 6 years ago

how is this related to hacking?

ineedasername4• 6 years ago

News articles from around April 10 indicate that mass testing hadn't begun, or was just beginning (1 example here [0])

Reporting on 96% without symptoms is misleading without mentioning this: It gives the impression that the # of coronavirus infections could be up to 24x higher than the known positives cases. But symptoms can take 2-14 days to develop, meaning it is entirely too soon to tell if these are all asymptomatic cases, or merely pre-symptomatic.

[0] https://www.dispatch.com/news/20200410/coronavirus-in-marion...

ineedasername4• 6 years ago

I see a lot of people dismissing the shared air space & HVAC systems as possible vectors of infection besides close contact, but you have to remember a very important factor:

Droplets exist in a continuum, not a binary of big == fall to ground, small == stay in the air. There's a range, and as they get smaller they stay in the air longer.

Large droplets (>50 μm in diameter) settle on the ground almost immediately, and intermediate-sized droplets (10–50 μm) settle within several minutes. Small particles (<10 μm), including droplet nuclei from evaporated larger particles, can remain airborne for hours and are easily inhaled deep into the respiratory tract. [0]

As such, while particles that stay aloft longer may not exists in sufficient quantities when it is just one infected, or a few infected inmates, that changes with the # of infected. With each infected inmate the concentrations of those small particles will increase.

Let's say that normally the small particles exist at 3% the necessary quantity to infect another person. Then 33 inmates and staff get sick through close contact, and all of a sudden the concentrations of small droplets is sufficient to infect people. You hit a critical mass, and each additional infection only makes it worse, creating a rapid downward spiral.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4147198/

In 4 US state prisons, 3,300 inmates test positive, 96% without symptoms

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