Asymptomatic Transmission...

[kellehi]

First of all, I'm aware that this will probably start a pile on, but I was intending to reply to @MarshaBradyo as we were discussing the basis for asymptomatic transmission, and I promised that I'd dig out the RKI paper that in February 2020 first started up the reasoning that Covid-19 was primarily being spread by asymptomatic transmission and the discussions critiquing it... However, the thread presumably reached its page limit and had gone off topic anyway, as long threads are prone to do...

Since we have seen little actual evidence on the basis of claiming asymptomatic transmisson is a substantial driver of the Covid-19 outbreak compared to symptomatic transmission except from appeals to authority - i.e. 'X government scientist said so' without providing reference to sources, I started out wondering, does anyone have any ideas on what basis were experts claiming that Covid-19 asymptomatic spread is a thing and we needed to lock down in March last year? Are there any studies, peer reviewed papers, other sources that I can read up on?

At the time I thought it'd be incredibly hard to prove definitively that someone who is asymptomatic for Covid-19 is spreading the virus, and probably would be extremely unethical to carry out a study whereupon you expose people to known asymptomatic (tested positive but not unwell) patients to see if they developed symptoms later. So I did some research to try to uncover what was the basis for determining asymptomatic transmission at the start of the outbreak.

I tried asking around and I got 'we know better, don't you know this is a thing, the Robert Koch Institute have proved this, and by the way there's people dying of this stuff being infected by their family members who are tested and found to be asymptomatic'

Doing some digging on their paper reveals a link that says "Study claiming new coronavirus can be transmitted by people without symptoms was flawed". and further down the page is an article right from the start of the pandemic when there were little to no other existing sources of asymptomatic transmission to rely on...

www.medpagetoday.com/infectiousdisease/publichealth/84688

Asymptomatic transmission of the novel coronavirus in Germany was called into doubt on Monday when an article appeared to question the research behind it.

Science magazine detailed errors in the New England Journal of Medicine (NEJM) research letter published last Thursday. The letter reported that asymptomatic transmission of novel coronavirus occurred in Bavaria, Germany, when several co-workers of an asymptomatic woman traveling from China contracted the virus.

The letter, and several media reports, said that the woman wasn't sick when she was in Germany and only began to feel ill on the plane ride home. Turns out that wasn't quite true.

Researchers who wrote the NEJM letter did not speak to the woman herself, according to Science. But after she spoke to officials from the Robert Koch Institute, Germany's public health agency, and Bavarian officials, she said that she "felt tired, suffered from muscle pain," and took fever-lowering medication while in Germany.

While Germany's health agency spokespeople would only confirm that the woman had symptoms, the Robert Koch Institute has submitted a letter to NEJM, presumably to correct the record.

China has claimed to have data showing asymptomatic transmission occurring within the country, but U.S. health officials previously said that they did not have enough data to make that claim. That appeared to change after the publication of the NEJM letter.

Indeed, asymptomatic transmission outside China was alluded to when the U.S. declared a public health emergency for novel coronavirus on Friday. And on Saturday, the World Health Organization (WHO) reported "third-generation" transmission of the virus in Germany.

Science said that WHO officials and European partner agencies have been notified with the new information. As of Tuesday, NEJM has not published a letter of correction.

Last Updated February 04, 2020

Two comments from below the article:

Brant S MIttler, MD JD (perhaps the same as medicine.duke.edu/faculty/brant-s-mittler-md)

February 5, 2020

I have been tweeting for some time now for some federal agency or an on-the-ball media outlet to please tell us ALL of the evidence that there is "asymptomatic transmission" of the virus. Being a "nobody," nobody responds. Maybe one of the editors or writers or maybe even the new Editor in Chief of this august online publication could break out of the pack and assemble and publish that evidence? As to the 10 yo boy with pneumonia who was supposedly asymptomatic, my pediatric colleagues doubt that patient was truly asymptomatic. Since we now have a public health emergency, it seems reasonable to look at the quality of the evidence for "asymptomatic transmission." Now I will sit back and wait for all the infectious disease and public health mavens to educate us.

Reza Nassiri (perhaps this Professor... phmtox.msu.edu/people/faculty/nassiri/)

February 9, 2020

The German investigators hastily rushed to submit their report to NEJM without hypothesizing the “biological” basis of asymptotic 2019-nCoV. Most importantly, they failed to consult with epidemiologists and virologists while preparing their investigational report which turned out to be partially inaccurate. Take home message: while there are currently uncertainties of various kinds about Whuhan vial pneumonia, better consult with multidisciplinary science team rather than rushing to submit a report. Prof. Nassiri

@CuriousaboutSamphire

Not asymptomatic. Asymptomatic are people who NEVER develop symptoms... Ah! I see. You are using the ABSOLUTE definitions rather than any real world observations that might help understand the spread of covid!

OK!

Er, no.

Asymptomatic spread, as used by Public Health England, Hancock, Whitty, etc is used to refer to people walking about spreading the virus and never getting symptoms, not ever

Aysmptomatic and presymptomatic are not some fancy terms used only in obscure medical jargon that's different to the definition used by the man on the street.

Unless you are confused about what 'asymptomatic' means...

@CuriousaboutSamphire

Yes I know. Just like people believe they can achieve cold fusion, but they haven't managed it yet. It doesnt mean that cold fusion is inachievable. But it doesn't mean that it is either... You do know that makes no sense?! If you use that as your reasoning for anything you just wouldn't get out of bed!

That's laughable. Of course it makes sense that something unproven may exist. It also means that it may not... they just DON"T KNOW.

You work to prove your hypothesis, surely. You can do all the work you want on cold fusion, but inless you produce a paper filled with reproducible results, then your work may end up coming to a dead end. This doesn't mean that you should never try

Especially as asymptomatic transmission is something which was never found to exist for any other virus previously to Covid-19

HPV; do you classify transmission as symptomatic or asymptomatic?

hpv.md/hpv-transmission/#:~:text=A%3A%20Asymptomatic%20transmission%20is%20when,the%20HPV%20virus%20is%20spread
www.healthline.com/health/sexually-transmitted-diseases/hpv-without-warts#causes

It is a very important distinction actually. If someone is 'asymptomatic', never transmits disease and we only know they have covid in the first place by using unreliable testing then the whole house of cards comes down. I am aware. I am also aware that in real life the distinctions sometimes get blurred, which is why research is ongoing!

That's laughable. Of course it makes sense that something unproven may exist. It also means that it may not... they just DON"T KNOW. Yes... I think we all know that there are many aspects about Covid that remain unknown!

You work to prove your hypothesis, surely. You can do all the work you want on cold fusion, but inless you produce a paper filled with reproducible results, then your work may end up coming to a dead end. This doesn't mean that you should never try That wa sthe point I was making. And the reason researc continues, even when it needs to blur the distinctions between a- and pre-symptomatic in order to get better understanding of and procedures agains the virus!

No worse a scientist than one who clings to absolutes!

I guess part of the issue is too that none of the Covid-19 tests are actually that reliable. I don't know the exact stats but both the PCR and the Lateral flow tests are throwing false positives - particularly the LFT.
It wouldn't surprise me at all if a significant proportion of asymptotic cases never contracted Covid-19 in the first place.

For the record:

ASYMPTOTIC: it's maths: a line that approaches a curve but never touches, in more symple terms.

ASYMPTOMATIC: that doesn't have symptoms.

I would doubt the qualifications of any "Prof." who used the term asymptotic to mean no symptoms. (in the OP)

I had Covid asymptomatically. Obviously I didn't know I had it at the time (my partner had it with mild symptoms). I thought I had avoided it. The only reason I know I had it is that months later, I have spike protein antibodies specific to SARS-COV-2, as does my partner.

That too! I think people lose sight of the fact that we, random people not scientists, don't usually see any of the interim data, the on the fly hypotheses and opinion pieces in the BMJ, Lancet etc etc. We are usually oblivious to the science behind any of our medicines, until soemthing goes wrong.

But with Covid we are experiencing in real time and not understanding why there is so much dissent (aka discussion), conjecture (aka in the fly hypothesising) and different, often contradictory information (aka ongoing, developing data streams). We don't normally see it, are usually presented, at most, with the end result of a study, and are made to feel uncomfortable when various experts disagree, change their minds, have no set answers.

Add our lovely unbiased, well edcuated journalists who never ever shase a scary headline... and you have all sorts of incipient panic and lots of misunderstandings.

And it seems like there is much confusion about what are the false positive or false negative rates for tests.

Both for PCR and lateral flow tests, the main issues are the false negatives and much less so the false positives.

www.bmj.com/content/372/bmj.n823

Oh yes @Lweji well spotted

And if you take it right back to basics, last February many of those symptoms were not recognised as Covid symptoms.

It really doesn't matter does it?

If somebody is moving around amongst other people and transmitting the virus it really won't make much difference to the people who catch it from them whether the spreader goes on to develop symptoms or not. They still now have caught covid.

The problem is that people who show no symptoms are merrily mixing with others blind to the fact that they are infectious and that is what is of concern to folk who are scared of mixing with others for fear of catching covid.

Asymptomatic transmission (pre- or no pre-) means that measuring temperatures, asking for coughs, etc, is virtually useless.
By the time you know you have covid and stay at home or isolated, you'll have infected other people.

I think the time it did matter was back last March - as all on last week's podiums agreed. Ther would have been different decisions made had that, and other data, been known earlier. Even if not born out later, the suspicion of it would have meant a different approach.

And now, as we look at the worlds being vaccinated, it will become important again to guage what % of population will need to be vaccinated to be sufficient with each/any vaccination drive.

@Lweji

Asymptomatic transmission (pre- or no pre-) means that measuring temperatures, asking for coughs, etc, is virtually useless. By the time you know you have covid and stay at home or isolated, you'll have infected other people.

The flip side of the same argument. Also something that many are not used to having to hold.

It's like all of this requires us to accept that cognitive dissonance is normal in science

Hi I did a post and started by saying I appreciated your non combative reply on the old thread but it was full and I lost it.

I’m open to discussing it and changing views

Ok will read now and try to formulate thinking again.

The flip side of the same argument.

Can you explain what you mean?

Thanks for starting this thread. I’ll have to make time later to read the links properly.

@CuriousaboutSamphire that’s very well put.

OK. I don't hink I'll gettit ALL n one post, not even sure I have it all in my head at the moment, but it is a sort of Schrodinger's virus at that point, isn't it?

Asymptomatic transmission - needs to be researched to allow for it to be accounted for in any process such as coming out of lockdown. Proving it's existence, especially if it is a significant vector of infection, will change things.

Yet if it exists, as you say, then all that tempertaure measuring is useless.

Yet we do those measures because at the moment we don't know and can only do what we KNOW will have an effect. All of the testing becomes redundent if asymptomatic transmission is proven to be a significant factor

And yet we test, because it makes us feel safer, makes a difference that hopefully remains measurable, real, enables real decisions to be made. The road out of lockdown relies on it.

Which will have to change if we suddenly know that asymptomatic transmission is highly significant.

But we can't prove it exists yet

And round it goes!

Sorry about the typos, I need a new keyboard, too many keys are blank and I am doing this in between moments at my real work

I think it's an interesting question and one I keep returning to. PCR tests are extremely sensitive and, I suspect, if you randomly swabbed a population during the winter a significant proportion would test positive without symptoms. Pre Covid I think the explanation would have been that a good immune system fought off the virus before it multiplied enough to cause symptoms (they would also have antibodies). And I'm interested in why that hasn't been part of the discussion around Covid.

By focusing on a very small number of symptoms, people with 'colds', certainly early on when testing wasn't readily available might well have assumed it wasn't Covid. 10 months on, an antibody test might show they've been exposed but they may not remember the 'cold' and hence think they've been asymptomatic.

@Lweji

For the record:

ASYMPTOTIC: it's maths: a line that approaches a curve but never touches, in more symple terms.

ASYMPTOMATIC: that doesn't have symptoms.

I would doubt the qualifications of any "Prof." who used the term asymptotic to mean no symptoms. (in the OP)

It's quite clear that he means asymptomatic and English isn't his first language.

Asymptomatic spread, as used by Public Health England, Hancock, Whitty, etc is used to refer to people walking about spreading the virus and never getting symptoms, not ever.

That wasn't my understanding. From friends and colleagues in the NHS, Asymptomatic included symptoms of being unwell but not the 3 symptoms of temp, cough and loss of taste. The app was used to track people with other symptoms, send them for tests, and those positive but without the 3 main symptoms were recorded as asymptomatic.

I dont entirely believe in complete asymptomatic transmission of Covid and as you say - how could you derive it so early in the pandemic. It's more about data collection, categorisation and analysis in large quantities and at speed.

I’ve been in the sun all day and for some reason I find my brain clunking through this but I’ll give it a try

• if we separate asymptomatic and pre-symptomatic what would we change in policy?

• how do we know who is a and who is pre so don’t we still need a blanket approach?

• can we look at the university results with high cases, about 770 positive iirc and 10% symptomatic and think about if that means anything

But mostly the real effect is in hospital. If we lift we get overwhelming. If we use lockdown we get a lowering.

What would people do differently if this data is correct?