Proportion of infected that are asymptomatic as high as 80%?

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Keegan99
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8:48a, 4/15/20
AG
From China, so caveat emptor.

https://www.bloomberg.com/news/articles/2020-04-15/china-s-data-on-symptom-free-cases-reveals-most-never-get-sick

Quote:
China for the first time publicized a breakdown of people testing positive for the novel coronavirus without outward signs of being sick, revealing that those among them who remain symptom-free throughout infection are in the majority.

Among 6,764 people who tested positive for infection without showing symptoms, only one fifth of them -- 1,297 -- have so far developed symptoms and been re-classified as confirmed cases, China's National Health Commission spokesman Mi Feng said at a briefing in Beijing Wednesday.

Some 1,023 are still being monitored in medical quarantine to see if they develop symptoms. The rest -- 4,444 -- have been discharged from medical observation after recovering from the virus.


This would put asymptomatics in the ballpark of 66% to 80% of infections.
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Not a Bot
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8:54a, 4/15/20
AG
Exactly what test are they using to determine asymptomatic infection? Antibodies?

The antibody fingerstick tests they shipped to the UK and in some places the United States have been total crap.
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Diyala Nick
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9:10a, 4/15/20
AG
The German study from a few days ago, along with study of pregnant women in Boston and homeless in San Francisco seem to indicate that the % asymptomatic may be much higher than 80%.
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cone
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In reply to Keegan99 • 9:14a, 4/15/20
AG
so why did China make the WHO say there was no asymptomatic spread 6 weeks ago?

what was their angle at the time?

this would be amazing news but the message coming out of China is ridiculously mixed
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Keegan99
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In reply to Diyala Nick • 9:25a, 4/15/20
AG
Was there a study in Boston as well?

https://www.nbcnewyork.com/news/local/nyc-hospital-finds-high-covid-19-infection-rate-but-few-symptoms-in-pregnant-women/2372863/

Pregnant women in NYC had about 1/6 (33 of 215) test positive, with 4 showing immediate symptoms and 3 later showing a fever. Cannot find any follow-up on the other 26 as yet. So that's a HUGE gap.

But 26 out of 33 being asymptomatics would fall right in line with the 80% ballpark.
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CFTXAG10
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9:33a, 4/15/20
AG
If we continue to test for antibodies and confirm that it is 80% or higher asymptomatic that would be HUGE for getting back to somewhat "normal"
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JDCAG (NOT Colin)
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In reply to CFTXAG10 • 9:40a, 4/15/20
AG
Yeah, probably a bit of a double edged sword though.

The higher the % of asymptomatic, the higher % of the population likely has antibodies....but it also increases the difficulty dealing with it as we try to approach "life as normal", especially without a reliable antibody test and given that we are still likely nowhere near the saturation of immune folks needed to get to herd immunity pre-vaccine.
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CFTXAG10
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In reply to JDCAG (NOT Colin) • 9:54a, 4/15/20
AG
Yea I think it starts with a reliable antibody test. Make it as widely available as possible. Then report back the results of people who have them but never had any symptoms.
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Diyala Nick
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In reply to Keegan99 • 9:58a, 4/15/20
AG
Keegan99 said:
Was there a study in Boston as well?

https://www.nbcnewyork.com/news/local/nyc-hospital-finds-high-covid-19-infection-rate-but-few-symptoms-in-pregnant-women/2372863/

Pregnant women in NYC had about 1/6 (33 of 215) test positive, with 4 showing immediate symptoms and 3 later showing a fever. Cannot find any follow-up on the other 26 as yet. So that's a HUGE gap.

But 26 out of 33 being asymptomatics would fall right in line with the 80% ballpark.


My bad. It was NY. I think the interesting things with these studies is that they are testing people in hotspots who are not seeking treatment, and finding a ton of positives. The positives also don't include those asymptotic who have had it (and didn't know) and now have antibodies.

In the very short term, I don't think this is very meaningful in terms of reducing the threat to the healthcare system, in fact perhaps the opposite. However, it does seem to indicate that we may arrive at a high level of immunity much sooner than anticipated, and not endure multiple waves of this.

edit to add:

We may never know, but you wonder if the other common Corona viruses had a similar lethality and prevelance when they jumped to humans 100+ and 1000+ years ago.

I'll also go out on a limb and speculate that we are likely to see a mad rush to produce both a universal flu vaccine and a universal Corona virus vaccine because of this.
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goodAg80
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In reply to Not a Bot • 10:03a, 4/15/20
AG
Moxley said:
Exactly what test are they using to determine asymptomatic infection? Antibodies?

The antibody fingerstick tests they shipped to the UK and in some places the United States have been total crap.
"Ha ha ha. Let's tell them these fingersticks with Covid all over them are tests for the virus"
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Pasquale Liucci
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In reply to Diyala Nick • 10:06a, 4/15/20
AG
This also seems to jive with the anecdote from Marcus a few weeks back noting tons of ICU patients positive for COVID without suspecting.

One that jumps out to me is the guy in car wreck who had broken bones and was x rayed for that. On CXR they saw obvious bilateral pneumonia that is hallmark of COVID
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PJYoung
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10:10a, 4/15/20
AG
Would be amazing news.
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cone
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10:32a, 4/15/20
AG


we know so little
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CFTXAG10
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In reply to cone • 10:42a, 4/15/20
AG
I look at that as even more potential good news. It is "likely" people are walking around all over the place with this thing and don't even know it. OR had it at some point and don't even know it.
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Beat40
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10:50a, 4/15/20
I think antibody studies, taking into account the proper measures for misreads, have significant impact to our decision making going forward.

I'm all for going full speed ahead in this direction. Let's do it an get an idea of where we really may be.

Yearly flu cases are an estimate based on positive results that are sometimes only 30% right. Why can't we factor in misreads on antibody testing and begin to draw conclusions?
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cone
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In reply to CFTXAG10 • 10:52a, 4/15/20
AG
OR

it's that the type of person this thing is attacking and killing is sometimes odd and we don't know why its so debilitating to some (that would otherwise seem healthy) but not affecting wide swaths of people you would expect to be less healthy

it's very very strange

is it all about viral load? is there some underlying genetic component (IL6) that's setting some up for a bad case?
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BigBrother
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In reply to Not a Bot • 10:53a, 4/15/20
AG
Moxley said:
Exactly what test are they using to determine asymptomatic infection? Antibodies?

The antibody fingerstick tests they shipped to the UK and in some places the United States have been total crap.
It's China. They're probably grabbing several random citizens and throwing them into the same lab/room together for weeks and reviewing the results.
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Not a Bot
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In reply to cone • 10:55a, 4/15/20
AG
cone said:


we know so little


It is really critical to read the content of these papers. Not criticizing you, but the people tweeting about it and spreading misinformation.

The purpose of this paper was to determine how rapidly Covid can spread in homeless shelters with an aim to develop strategies to mitigate spread. In other words, they were actually investigating the effectiveness of temperature checks and symptom screenings.

They tested these people immediately after an outbreak at a shelter where 15 people had symptoms and were positive. They did not follow up on these asymptomatic people to see if they ended up developing symptoms. There is no information on how many of these people became ill later on.

No information can really be gleaned from this study other than the virus can spread quickly in close quarters, and temperature/symptom checks aren't really all that effective in determining who may be shedding the virus.

The primary conclusion from this paper is that testing should be done on a broader basis in homeless shelters as asymptomatic spread seems to be a very real thing.
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cone
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In reply to Not a Bot • 10:56a, 4/15/20
AG


here's follow up
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California Ag 90
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10:58a, 4/15/20
AG
if this report is accurate, i can't decide if, medically, this is positive or negative news.

any medical viewpoints on this?
We're from North California, and South Alabam
and little towns all around this land...
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Not a Bot
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In reply to cone • 11:00a, 4/15/20
AG
Those were symptoms at the time of testing. There was no follow-up. The conclusions being drawn by people on Twitter are not in line with the purpose of the study.
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cone
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In reply to Not a Bot • 11:01a, 4/15/20
AG
Quote:
During the last week in March, BHCHP observed an evolving cluster of COVID-19 cases emerging from a single large homeless shelter in Boston. With support from the Massachusetts Department of Public Health (MDPH), BHCHP rapidly conducted polymerase chain reaction (PCR) testing for SARS-CoV-2 along with focused symptom assessments among all guests residing at the shelter over a 2-day period.
it's been 2+ weeks

how many are dead? i know we don't know from the report and that's not the intent of their study, but i'd assume the shelter workers could fill us in.
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cone
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In reply to Not a Bot • 11:03a, 4/15/20
AG
we were expecting mass death events in California homeless populations due to this bug

has that materialized?

if it has, it's not being reported
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Not a Bot
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In reply to cone • 11:04a, 4/15/20
AG
Correct! We need more information to determine the actual percentage of people who stayed asymptomatic, which I hope is very high.
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Not a Bot
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In reply to cone • 11:09a, 4/15/20
AG
cone said:
we were expecting mass death events in California homeless populations due to this bug

has that materialized?

if it has, it's not being reported


I have no idea. Hopefully not. Would be curious to see if there's a study out there following up on asymptomatic positive PCR folks to see if / when they develop symptoms and outcome. Those are probably under way but are taking time due to the long course of illness.

Seems like this study of the homeless shelter population in Boston would be a great thing to follow up on. Hopefully they were able to get good identities and are able to track these people down again.
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Keegan99
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11:25a, 4/15/20
AG
The testing from the Boston homeless shelter occurred in late March.

We should know by now how many developed symptoms.
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Not a Bot
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In reply to Keegan99 • 12:16p, 4/15/20
AG
Keegan99 said:
The testing from the Boston homeless shelter occurred in late March.

We should know by now how many developed symptoms.


It would be great IF they followed up. But remember these studies have a particular plan for a particular purpose. Their purpose wasn't to test how many asymptomatic people stay asymptomatic, so they may not have even collected the right information on people to be able to follow up. Hopefully they did. I assume they had some sort of identifiable information due to the fact they were sending lab samples off to a lab to be tested, but it's possible the researchers didn't get to keep that information.

Unfortunately homeless folks can sometimes be pretty transient and it may be difficult to find some of them.
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Complete Idiot
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In reply to Not a Bot • 12:28p, 4/15/20
Moxley said:
cone said:


we know so little


It is really critical to read the content of these papers. Not criticizing you, but the people tweeting about it and spreading misinformation.

The purpose of this paper was to determine how rapidly Covid can spread in homeless shelters with an aim to develop strategies to mitigate spread. In other words, they were actually investigating the effectiveness of temperature checks and symptom screenings.

They tested these people immediately after an outbreak at a shelter where 15 people had symptoms and were positive. They did not follow up on these asymptomatic people to see if they ended up developing symptoms. There is no information on how many of these people became ill later on.

No information can really be gleaned from this study other than the virus can spread quickly in close quarters, and temperature/symptom checks aren't really all that effective in determining who may be shedding the virus.

The primary conclusion from this paper is that testing should be done on a broader basis in homeless shelters as asymptomatic spread seems to be a very real thing.
THANK YOU. I am so tired of people showing the text of a tweet as proof of something. Too many times I have actually clicked the link the random twitter person has embedded and it is some news article, Bloomberg or something, and then within that article is actually a link to the academic paper they are referring to. READ THAT, always. Do not rely on how the media person has decided to pick info or snippets out of the academic paper, and certainly don't rely on how some person on Twitter has decided to further play the telephone game by pulling key snippets out of the media article. Read the original report and draw your own conclusions.
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Zobel
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In reply to Not a Bot • 12:28p, 4/15/20
AG
Alex Berenson has consistently had awful, stupid, no good takes on this. It's either ignorance or malice, but I don't really care which. He pretty much should be ignored.
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Complete Idiot
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In reply to Keegan99 • 12:41p, 4/15/20
Keegan99 said:
From China, so caveat emptor.

https://www.bloomberg.com/news/articles/2020-04-15/china-s-data-on-symptom-free-cases-reveals-most-never-get-sick

Quote:
China for the first time publicized a breakdown of people testing positive for the novel coronavirus without outward signs of being sick, revealing that those among them who remain symptom-free throughout infection are in the majority.

Among 6,764 people who tested positive for infection without showing symptoms, only one fifth of them -- 1,297 -- have so far developed symptoms and been re-classified as confirmed cases, China's National Health Commission spokesman Mi Feng said at a briefing in Beijing Wednesday.

Some 1,023 are still being monitored in medical quarantine to see if they develop symptoms. The rest -- 4,444 -- have been discharged from medical observation after recovering from the virus.


This would put asymptomatics in the ballpark of 66% to 80% of infections.
You know, I am not sure if that is the right interpretation - but I hope it is.

WIthin the Bloomberg article I clicked on the link to the China report (it's in CHinese but can be translated). I see this snippet:

Regarding people with asymptomatic infection, let me explain one more case. As of April 14, a total of 6,764 cases of asymptomatic infections have been reported nationwide, including 588 cases imported from abroad; 1297 cases have been confirmed as diagnosed cases, including 251 cases imported overseas; 4444 cases have been released from medical observation, including 109 cases imported from abroad 1023 cases of asymptomatic infections still under medical observation, including 228 cases imported from abroad.

Is this saying 6764 of their 82,000 total cases were asymptomatic? And that 1297 confirmed as diagnosed means what? Maybe something lost in translation or my interpretation.

I am not sure if they are saying 6764/82000 total are asymptomatic, or 8% of total cases. Rather than how it's being interpreted by Bloomberg author.
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pocketrockets06
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In reply to California Ag 90 • 12:45p, 4/15/20
AG
Both, depends on what you previously believed about the disease.

Current US CFR is about 6.5% (deaths / cases from 7 days ago) so if 80% of people are asymptomatic (and thus not getting tested and not included in the cases) it would suggest the IFR (infection fatality rate) is more like 1.3%.

That's not that far off what South Korea is seeing of 2% (we could maybe assume that even though their testing regime is capturing more people, its still missing some people) so this supports the initial assumption of many epidemiologists of a fatality rate of 1-2% for those infected.

That's the range I've been assuming for this event. If you were a person assuming 0.05% (H1N1) or 0.1% (1957 Asian Flu), then this is bad news and this pandemic is worse than you think. If you were assuming higher (2.5%? Spanish Flu), then this is probably good news.

At 1-2%, I think our shutdowns are fully justified as that's 3-6 MM dead in the US alone (not including losses from overrun healthcare).
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Keegan99
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In reply to pocketrockets06 • 12:50p, 4/15/20
AG
There's also a significant number of people that are symptomatic but never get tested because they're not in at risk demographic. So they're never counted as a confirmed case.

(This may not be as true today as it was several weeks ago, as testing is currently more widely available.)
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DTP02
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In reply to Keegan99 • 12:59p, 4/15/20
AG
Keegan99 said:
From China, so caveat emptor.

https://www.bloomberg.com/news/articles/2020-04-15/china-s-data-on-symptom-free-cases-reveals-most-never-get-sick

Quote:
China for the first time publicized a breakdown of people testing positive for the novel coronavirus without outward signs of being sick, revealing that those among them who remain symptom-free throughout infection are in the majority.

Among 6,764 people who tested positive for infection without showing symptoms, only one fifth of them -- 1,297 -- have so far developed symptoms and been re-classified as confirmed cases, China's National Health Commission spokesman Mi Feng said at a briefing in Beijing Wednesday.

Some 1,023 are still being monitored in medical quarantine to see if they develop symptoms. The rest -- 4,444 -- have been discharged from medical observation after recovering from the virus.


This would put asymptomatics in the ballpark of 66% to 80% of infections.


Interesting.

Article doesn't say how the people were selected for the study, so I guess you have to leave open the possibility that the selection criteria is skewing the asymptomatic numbers.

Like maybe they Just asked people if they were showing symptoms and people were hesitant to admit it because they didn't want to get thrown into the crematorium while still alive (only half joking).
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Complete Idiot
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12:59p, 4/15/20
I don't believe 80% would test positive and be asymptomatic. Iceland tested 10% of their population and found 50% were asymptomatic AT THE TIME, but I couldn't find info on how many later got symptoms. We know you can have this 1-14 days, for most, without symptoms. I would love, LOVE to believe 80% are asymptomatic but I believe it's wishful thinking. I think Diamond Princess was around 20% NEVER showed symptoms and that's better than nothing. I now that's not exhaustive, just another data point.

I can believe 80% who have had this never got a test and arent counted in the nation's confirmed positive. It's believable anyway. Lots of people told to stay home and don't get tested unless symptoms are bad.

WIDESPREAD ANTIBODY TESTS (screams everyone)
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California Ag 90
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In reply to pocketrockets06 • 1:24p, 4/15/20
AG
pocketrockets06 said:
Both, depends on what you previously believed about the disease.

Current US CFR is about 6.5% (deaths / cases from 7 days ago) so if 80% of people are asymptomatic (and thus not getting tested and not included in the cases) it would suggest the IFR (infection fatality rate) is more like 1.3%.

That's not that far off what South Korea is seeing of 2% (we could maybe assume that even though their testing regime is capturing more people, its still missing some people) so this supports the initial assumption of many epidemiologists of a fatality rate of 1-2% for those infected.

That's the range I've been assuming for this event. If you were a person assuming 0.05% (H1N1) or 0.1% (1957 Asian Flu), then this is bad news and this pandemic is worse than you think. If you were assuming higher (2.5%? Spanish Flu), then this is probably good news.

At 1-2%, I think our shutdowns are fully justified as that's 3-6 MM dead in the US alone (not including losses from overrun healthcare).
thanks, helpful.

is the ratio of (current deaths)/(cases as of one week ago) a standard? i've seen metrics all over the map and a standard ratio if it exists would be very helpful.

We're from North California, and South Alabam
and little towns all around this land...
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