Continuation The One Covid-19 Science and Medicine Thread Part 2

[The Atheist]

Originally Posted by marting

I suspect most of the "close" peeps were people in the home they stayed in. Details are in the study.

I'll see if I can find it, because I agree that you'd expect a lot higher percentage of people in the same house to get it.
____________________________

Dr Sid: What's happening in Chechia?

You numbers appear to have taken a turn in the wrong direction, immediately after loosening restrictions.

Don't be America!

[wasapi]

https://www.nj.com/coronavirus/2020/...say-maybe.html

I'm sorry if this topic has been posted about already. I saw this discussed on TV recently, then came upon this article. It is interesting,

[Skeptic Ginger]

Originally Posted by Arcade22

Sweden has kept preschools and primary schools open and it has basically not seen any signs that children spread the disease to any significant degree either among themselves or to adults. Teachers and other school staff members are far more likely to infect each-other than being infected by the kids.

There has so far only been one single significant outbreak at a school where a lot of teachers were sick and one of them ended up dying, which eventually had to close prematurely for the summer due to a lack of sufficient teachers. I live fairly close to this school and it was a very exceptional event especially given the low rate of infection in this region.

Teachers are not any more likely to be infected than anyone else.

How do you know kids aren't silent spreaders?

[Skeptic Ginger]

Originally Posted by marting

Some do many don't. The FDA has been coming down a some of the hundred plus purveyors of antibody tests that haven't even applied for an emergency authorization. Many of those are crap. Some tests deployed in Japan in a large group that hasn't had Covid-19 has a positive rate of under 0.1% so at least that test had decent specificity. Sensitivity, OTOH, is harder to quantify as there are fewer known positives to test against.

Is this a separate issue than prevalence studies?

Because regardless, we don't have good prevalence studies.

[marting]

Originally Posted by Skeptic Ginger

Is this a separate issue than prevalence studies?

Yes.

Quote:

Because regardless, we don't have good prevalence studies.

I agree. They aren't that good. Selection bias looks to be an issue in the ones I've seen.

[William Parcher]

Originally Posted by marting

The link is the full pdf of the study. IIRC, the "close" was people that had spent over 15 minutes closer than 2m

With or without masks?

Quote:

as well as people in the same household.

With or without masks?

[marting]

Originally Posted by Skeptic Ginger

How do you know kids aren't silent spreaders?

The study I linked above was an antibody study. In that only 1 child under 10 of over 100 that had lived in a household with a Covid-19 case tested positive for antibodies.

That doesn't say children that are infected can't be spreaders but it does suggest children are unlikely to be infected.

[William Parcher]

Originally Posted by marting

Also of note is the study is base on close contacts of Covid-19 patients. Testing showed that 51% of the close contacts had acquired Covid-19.

With or without masks?

[marting]

Originally Posted by William Parcher

With or without masks?

Masks were not commonly in use at the time and were not generally recommended. Study was antibody based to look back in time. Beyond that read the paper.

[William Parcher]

Originally Posted by marting

Here's an interesting study out of China (financed in part by the US NIH) that showed about half secondary transmission was from people that were pre-symptomatic.

I have an idea, but could you please describe the difference between pre-symptomatic and asymptomatic?

[marting]

Originally Posted by William Parcher

I have an idea, but could you please describe the difference between pre-symptomatic and asymptomatic?

Everyone that becomes symptomatic was pre-symptomatic between the point of exposure and developing symptoms. This is referred to as the incubation period. Asymptomatics refer to people that were infected but have never had symptoms.

[Orphia Nay]

Originally Posted by marting

That's consistent with the Swiss study. Frankly, I was surprised by the almost non-existent transmission to children. Even in families where a person had Covid-19. There's clearly something different going on.

OTOH, for people 20 or more it seems they are all pretty susceptible to getting the bug. Even though it impacts older people far harder.

Elsewhere it's been reported that pregnant women don't transmit it to their newborns. Even when they may get it themselves. Curious.

The pre-existing health of the population/individuals is known to be a factor.

Plus, I've seen immunologists say a virus can change when it is transmitted -HEAR ME OUT - probably in the same way each time for most children. It's not as severe if they've fought it off a bit.

Blah blah blah we don't understand herd immunity, yeah.

[Samson]

The great majority of cases testing positive in quarantine in New Zealand are arriving from India.
Maybe 8 of about 12 a week
.

[casebro]

Originally Posted by TellyKNeasuss

The latest from the CDC:
- the US is likely only testing 5 to 8 percent of those infected.
- 3% of US counties currently have a high transmission rate
- conditions giving a high risk of a serious case are: chronic kidney disease, serous heart disease, sickle cell disease, COPD, weakened immune system from organ transplant, type 2 diabetes, and a BMI > 30 (60% of American adults have at least 1 of these!)
......
https://www.washingtonpost.com/healt...-times-larger/

Do we know how many deaths are in the 40% without risk factors? If it's40%, then the definition of risk factors is bogus science. IF it is greater than 40%, then those are actually protective factors. Whatever the math, I don't think those risk factors are very strong. Rather than age or health, I think the big risk factor of catching it is environment. Like meat processing plants, care homes,... But no doubt the frail will have a higher death rate. But 99.4% of us are not going to die form it, only catch it. So let's get practical about living life while not catching it.

Shouldn't there be CDC Epidemiologists making tallies?

[The Atheist]

Originally Posted by marting

I think otherwise. At least in the USA. There's been a big shift towards the younger crowd out having fun at bars. Older folks are still being cautious for the most part. Very different from the early days where a lot of the cases were older people who probably get a more serious case, spread it more easily, and didn't know the consequences at the time.

Now they do. Fewer going to church. Singing in choirs, or playing bingo indoors.

I hope you're right, because if USA is anything like NZ was when masks were advised, the least likely people to wear them were the worst age demographic.

Originally Posted by marting

Maybe 25% less deaths between the two known effective agents.

There's going to be a lot more cases, though, so I'm the other way - I'll be surprised if deaths don't surpass the earlier totals.

Give it a couple of weeks and we'll know.

Originally Posted by Samson

The great majority of cases testing positive in quarantine in New Zealand are arriving from India.
Maybe 8 of about 12 a week
.

Yeah, I was shocked to see that.

Given the number who got through without testing - or are now refusing to be tested - if it breaks out in the community, it'll be in Mt Roskill first.

Or where I live - 30% in the area are Indians.

[novaphile]

Originally Posted by Samson

The great majority of cases testing positive in quarantine in New Zealand are arriving from India.
Maybe 8 of about 12 a week
.

Tell me about it.

We're expecting more new cases, purely because we're still repatriating people from India.

[Skeptic Ginger]

Originally Posted by marting

The study I linked above was an antibody study. In that only 1 child under 10 of over 100 that had lived in a household with a Covid-19 case tested positive for antibodies.

That doesn't say children that are infected can't be spreaders but it does suggest children are unlikely to be infected.

Way too small/limited to be considered more than anecdotal evidence.

A few minutes searching for prevalence of COVID 19 in kids turns up a study of a couple thousand kids who were diagnosed with the virus and they tend to have mild or asymptomatic cases. All the reports suggest kids are indeed susceptible to the virus.

CDC COVID 19: Information for Pediatric Healthcare Providers

Quote:

There have been multiple reports to date of children with asymptomatic SARS-CoV-2 infection.3,6,14,15 In one study, up to 13% of pediatric cases with SARS-CoV-2 infection were asymptomatic.16 The prevalence of asymptomatic SARS-CoV-2 infection and duration of pre-symptomatic infection in children are not well understood, as asymptomatic individuals are not routinely tested.

CDC MMWR: Coronavirus Disease 2019 in Children — United States, February 12–April 2, 2020

Quote:

Among all 2,572 COVID-19 cases in children aged <18 years, the median age was 11 years (range 0–17 years). Nearly one third of reported pediatric cases (813; 32%) occurred in children aged 15–17 years, followed by those in children aged 10–14 years (682; 27%). Among younger children, 398 (15%) occurred in children aged <1 year, 291 (11%) in children aged 1–4 years, and 388 (15%) in children aged 5–9 years. Among 2,490 pediatric COVID-19 cases for which sex was known, 1,408 (57%) occurred in males; among cases in adults aged ≥18 years for which sex was known, 53% (75,450 of 143,414) were in males. Among 184 (7.2%) cases in children aged <18 years with known exposure information, 16 (9%) were associated with travel and 168 (91%) had exposure to a COVID-19 patient in the household or community. ...

Discussion
Among 149,082 U.S. cases of COVID-19 reported as of April 2, 2020, for which age was known, 2,572 (1.7%) occurred in patients aged <18 years. In comparison, persons aged <18 years account for 22% of the U.S. population (3).

Those are cases that were diagnosed because they came to the attention of a health care provider. And this was during the time the CDC was discouraging testing of mild or asymptomatic cases unless there was a known exposure. We know from the cases in WA State that the virus was being spread for weeks before it was recognized. Because there was a shortage of tests, we still were told not to test people who were mildly ill if they didn't have a known exposure.

And even if only 2% of kids were getting infected (and we know it's more than that) that still represents a significant reservoir of disease.

Epidemiology of COVID-19 Among Children in China

Quote:

CONCLUSIONS: Children of all ages appeared susceptible to COVID-19, and there was no significant sex difference. Although clinical manifestations of children’s COVID-19 cases were generally less severe than those of adult patients, young children, particularly infants, were vulnerable to infection. The distribution of children’s COVID-19 cases varied with time and space, and most of the cases were concentrated in Hubei province and surrounding areas.

A lot of people who would love to send kids back to school are willing to believe they are not a problem in the spread of this virus. There are lots of rationales why kids are immune before it has even been established that they are. The evidence we do have suggests they are not immune.

[Skeptic Ginger]

Originally Posted by Orphia Nay

The pre-existing health of the population/individuals is known to be a factor.

Plus, I've seen immunologists say a virus can change when it is transmitted -HEAR ME OUT - probably in the same way each time for most children. It's not as severe if they've fought it off a bit.

Blah blah blah we don't understand herd immunity, yeah.

All viruses mutate. Not all mutations are significant.

So far the mutations seen in COVID 19 have not been significant. There is a suggestion one clade might be more infectious than the other clades. I'm not sure if that has been established yet. But this virus is not going through any major changes.

[Arcade22]

Originally Posted by Skeptic Ginger

How do you know kids aren't silent spreaders?

Because teachers are not at any increased risk of being infected.

[Orphia Nay]

Originally Posted by Skeptic Ginger

All viruses mutate. Not all mutations are significant.

So far the mutations seen in COVID 19 have not been significant. There is a suggestion one clade might be more infectious than the other clades. I'm not sure if that has been established yet. But this virus is not going through any major changes.

And as I said, 80% of cases are mild.

[Orphia Nay]

The Times on Britain's leading epidemiologist:

Quote:

a report titled Contingency Planning for a Possible Influenza Pandemic. It was dated 2006, towards the end of King’s term, and published by the UK Cabinet Office.

This document considers a range of measures for a possible pandemic. Employers, it says, should be prepared for a large number of absences during the two to three-week peak. The country should be prepared to have 350,000 deaths in the first wave, but, “Key messages from the government during a pandemic will be that people who are well should carry on with normal, essential activities as far as possible, at the same time taking personal responsibility for self-protection.”

Some measures to “reduce social mixing” may be necessary. These include closing large events. But the overall aim should be, it summarises, to minimise disruption as much as possible, while the virus passes through society.

Fourteen years after that document – the considered thoughts of the government at the time – King is explaining to me the correct response in the early stage of a pandemic. “You have to understand exponential growth. As soon as you know that the curve is going up and cases are doubling every two to three days, as soon as you know that, surely you would go into lockdown at that point?”

Put like this, it does sound sensible. But, I say, if I might refer him to the UK’s 2006 pandemic plan, produced in the tenure of one D King, the advice seems to be a little different. In fact, it feels a little bit – how should I put this? – a little bit like herd immunity.

King barely misses a beat. “You’re right. But on the other hand, what we also did very clearly say, I believe – and maybe my memory is a bit faulty here – is you have to get ahead of the epidemic. In other words, look at the people coming into your countries, and test and trace is absolutely key to any epidemic.”

https://www.thetimes.co.uk/article/s...-now-nvhdxf7p9

[Samson]

I think there is a credibility gap.
Eradication is essential.
Rolfe is describing Scotland's endeavours that will probably work, New Zealand has succeeded.
Always aim high dear worldlings.

[marting]

Originally Posted by Skeptic Ginger

Way too small/limited to be considered more than anecdotal evidence.

While not a large sample size, 1 positive out of 123 kids between the age of 5 and 9 that were in a Covid-19 household is statistically significant (95%) at the 5% transmission level. The problem is more likely the Elisa test used which was only validated for adults. Given the much higher China study level you linked to, this seems a likely source of error.

Quote:

CDC COVID 19: Information for Pediatric Healthcare Providers

[WhatRoughBeast]

Originally Posted by Myriad

All the statistics sites list "deaths reported that day." "Reported" means reaching the final stage of the information being received and listed by the relevant state agency and then getting passed on to whomever's posting the graphs. The weekly patterns relate mostly to which hospital departments and public health departments and intermediate state agencies are closed on weekend days, meaning not many of them reach the final tally point on Sun. or Mon.

While that is a perfectly reasonable explanation, I have my doubts.

Let's say deaths are running 1,000 per day. 40% of agencies don't report on weekends. Then, come Monday and Tuesday, there will be an additional 800 deaths which have to be added to the correct totals, and this would (as far as I can figure it) produce a fairly massive overshoot in the Wednesday / Thursday totals. But there is nothing which looks statistically significant in the other five days' totals.

[Trebuchet]

So, (rule of), is what the USA is now seeing the "second wave" or still the first one? I'm thinking still the first, since it's striking in a lot of places that didn't have it so much in the Spring.

[The Atheist]

Originally Posted by Trebuchet

So, (rule of), is what the USA is now seeing the "second wave" or still the first one? I'm thinking still the first, since it's striking in a lot of places that didn't have it so much in the Spring.

Definitely still the first wave, as Fauci has stated on numerous occasions.

And still with a very long way to go.

[Skeptic Ginger]

Originally Posted by Arcade22

Because teachers are not at any increased risk of being infected.

This article in Nature looks like a good summary of the current science:

How do children spread the coronavirus? The science still isn’t clear

It is almost 2 months old so there might be better research by now. I'm not buying the assertion teachers in Sweden aren't getting COVID 19 without some actual research.

But whether kids play a minor role in the spread of COVID 19, I'll keep an open mind.

[Skeptic Ginger]

Originally Posted by Orphia Nay

And as I said, 80% of cases are mild.

There's no question about that.

You wouldn't want to expose thousands of kids to the virus, however, without concern for the small number that do experience life threatening disease. There's no way to know if your kid will be the one that is the exception.

[Aridas]

Originally Posted by Trebuchet

So, (rule of), is what the USA is now seeing the "second wave" or still the first one? I'm thinking still the first, since it's striking in a lot of places that didn't have it so much in the Spring.

Generally speaking, I would call it the first wave. Some places in the US are at risk for a second wave - New York City, for example, but for most of the US, it's first wave. For there to be a second wave, it's pretty much necessary for the first wave to have significantly gone down, and plateaus don't really count.

[Skeptic Ginger]

Originally Posted by marting

While not a large sample size, 1 positive out of 123 kids between the age of 5 and 9 that were in a Covid-19 household is statistically significant (95%) at the 5% transmission level. The problem is more likely the Elisa test used which was only validated for adults. Given the much higher China study level you linked to, this seems a likely source of error.

I'm not going to argue with you. Unless the research is repeatable, it's not very meaningful. You don't know, was the antibody test reliable, was the population protected because of some other means.

See my post with the Nature article link. There's a good discussion of the wide range of results and possibilities with regard to the role of children in the spread of COVID 19.

You know the common saying, extraordinary claims require at least more than a minimal level of evidence. It would indeed be extraordinary if it turned out kids were not a major spreader of this virus.

Possible, but you need more evidence than one single small study.

[Skeptic Ginger]

Originally Posted by Trebuchet

So, (rule of), is what the USA is now seeing the "second wave" or still the first one? I'm thinking still the first, since it's striking in a lot of places that didn't have it so much in the Spring.

A "second wave" would mean after the first wave was pretty much over. The second wave in the 1918 flu was the following year.

This is still the first wave.

[JeanTate]

Originally Posted by casebro

Do we know how many deaths are in the 40% without risk factors? If it's40%, then the definition of risk factors is bogus science. IF it is greater than 40%, then those are actually protective factors. Whatever the math, I don't think those risk factors are very strong. Rather than age or health, I think the big risk factor of catching it is environment. Like meat processing plants, care homes,... But no doubt the frail will have a higher death rate. But 99.4% of us are not going to die form it, only catch it. So let's get practical about living life while not catching it.

Shouldn't there be CDC Epidemiologists making tallies?

Apples and oranges are not the only fruits.

There are those who catch it, get very sick, and recover fully (after a while).

And those who catch it, get very sick, but never fully recover (Covid-19 as a new chronic condition).

Those who catch it, don’t get very sick, but still end up being sick for the rest of their lives.

Etc.

And there’s things that are not fruit; for example, “I caught it in March 2020, got sick, and recovered. But in March 2021, I caught it again, got very sick, and will very likely die”.

[JeanTate]

Originally Posted by marting

Everyone that becomes symptomatic was pre-symptomatic between the point of exposure and developing symptoms. This is referred to as the incubation period. Asymptomatics refer to people that were infected but have never had symptoms.

I wonder to what extent being “asymptomatic” is poorly understood, or arbitrary.

Some hypotheticals:

- “the screener asked me if I had a fever, headache, and/or dry cough. Over the phone. I said no, even though I had all three. Ten days later, when I truly did feel fine, I had a nasal swab.”

- “the doctor asked me ..., and took my temperature, and a nasal swab.”

- “the screener, a volunteer, asked me ... I did have a temperature and a low grade fever, but I have those all the time because I have [chronic condition].”

- asymptomatics who are false positives.

[JeanTate]

Originally Posted by alfaniner

Just wondering - in addition to masks, why not full-face motorcycle helmets as an alternative? People could then see your face and you could even install a little filtered fan for some air circulation (with some other minor modifications). Plus, it's great protection for if you fall down!

OK, they're much more expensive, but plenty of people have them already. I've seen people wearing ski or airsoft masks, but those still obscure your mouth and nose.

I have seen a health care worker (a tech, I think) wearing something like just such a helmet.

[JeanTate]

Originally Posted by The Atheist

The CDC has also come out and stated they believe infections are under-stated by a factor of 10, with 20M Americans having had Covid to date: https://www.npr.org/sections/coronav...-at-highest-ri

I think we can be fairly confident that the same applies everywhere, giving a likely mortality rate of 0.5% overall.

There’s still, for the US at least*, the puzzle of why African Americans, Hispanics, and Asian Americans (in that order) seem to have a higher IFR. Even when adjusted for age and pre-existing conditions.

*or at least some parts of the US

[JeanTate]

Originally Posted by JeanTate

I wonder to what extent being “asymptotic” is poorly understood, or arbitrary.

Some hypotheticals:

- “the screener asked me if I had a fever, headache, and/or dry cough. Over the phone. I said no, even though I had all three. Ten days later, when I truly did feel fine, I had a nasal swab.”

- “the doctor asked me ..., and took my temperature, and a nasal swab.”

- “the screener, a volunteer, asked me ... I did have a temperature and a low grade fever, but I have those all the time because I have [chronic condition].”

- asymptomatics who are false positives.

Right on cue ... “How the World Missed Covid-19’s Silent Spread” (NYT earlier today, link to follow). Contains at least one example, though more about pre-symptomatic than asymptomatic.

ETA: link https://www.nytimes.com/2020/06/27/w...mptomatic.html

[Ulf Nereng]

Two milestones have been reached: Over 10 million confirmed cases, and 500 000 dead.

[TellyKNeasuss]

Originally Posted by JeanTate

There’s still, for the US at least*, the puzzle of why African Americans, Hispanics, and Asian Americans (in that order) seem to have a higher IFR. Even when adjusted for age and pre-existing conditions.

*or at least some parts of the US

Are you sure that Hispanics have a higher IFR than white Americans? They have a slightly higher fatality per million ratio than white Americans but I thought that they had a substantially higher rate of infection.

[marting]

Originally Posted by JeanTate

I wonder to what extent being “asymptomatic” is poorly understood, or arbitrary.

Some hypotheticals:

- “the screener asked me if I had a fever, headache, and/or dry cough. Over the phone. I said no, even though I had all three. Ten days later, when I truly did feel fine, I had a nasal swab.”

- “the doctor asked me ..., and took my temperature, and a nasal swab.”

- “the screener, a volunteer, asked me ... I did have a temperature and a low grade fever, but I have those all the time because I have [chronic condition].”

- asymptomatics who are false positives.

This is a very good point.

I've looked for studies that explore variations in how people are characterized as symptomatic or not. This really isn't that hard a study to do and might yield better info on Covid-19 effects.

Who doesn't wake up and perhaps cough? Symptoms are quite nebulous and frankly, pretty common. I sneeze about half the time after I eat. And sometimes I'll cough a bit non-productively. But it's just something I've always done as long as I remember.

[JeanTate]

Originally Posted by TellyKNeasuss

Are you sure that Hispanics have a higher IFR than white Americans? They have a slightly higher fatality per million ratio than white Americans but I thought that they had a substantially higher rate of infection.

My bad.

I really shouldn’t rely on memory!

What I remembered was a CDC document, dated 25 June, “COVID-19 in Racial and Ethnic Minority Groups”, as well as something from either NYC or NY state Health (neither of which I can find just now ).

The CDC document is about hospitalizations, and is adjusted for age (but not underlying health conditions).