Johnson & Johnson vaccine is temporarily suspended while they investigate an illness. We’ve already learned that such pauses are not uncommon.
Meanwhile, the AstraZeneca trial in the US remains on hold while an FDA review continues.
Order of Kilopi
Johnson & Johnson vaccine is temporarily suspended while they investigate an illness. We’ve already learned that such pauses are not uncommon.
Meanwhile, the AstraZeneca trial in the US remains on hold while an FDA review continues.
I may have many faults, but being wrong ain't one of them. - Jimmy Hoffa
Order of Kilopi
Originally Posted by Copernicus
Perhaps worth pointing out that this settled down a couple of weeks ago. The CDC's How Coronavirus Spreads page has an accompanying Scientific Brief about aerosol transmission which says, among other things:In other words, the real-world epidemiology says aerosol transmission is rare, despite all the concerns raised by laboratory and simulation studies (and the various allegedly "epidemiological" studies performed by non-epidemiologists).Diseases that are spread efficiently through airborne transmission tend to have high attack rates because they can quickly reach and infect many people in a short period of time. We know that a significant proportion of SARS-CoV-2 infections (estimated 40-45%) occur without symptoms and that infection can be spread by people showing no symptoms. Thus, were SARS-CoV-2 spread primarily through airborne transmission like measles, experts would expect to have observed considerably more rapid global spread of infection in early 2020 and higher percentages of prior infection measured by serosurveys. Available data indicate that SARS-CoV-2 has spread more like most other common respiratory viruses, primarily through respiratory droplet transmission within a short range (e.g., less than six feet). There is no evidence of efficient spread (i.e., routine, rapid spread) to people far away or who enter a space hours after an infectious person was there.
This is something I've already pointed out more than once on this thread, whenever the aerosol spectre has raised its head. I'd just like to say that I in no way pressurized the CDC to fall into line with my views.
Grant Hutchison
Order of Kilopi
https://www.pnas.org/content/117/22/11875
Droplets, speech droplets and their Virion load. The authors point out that largish 50 micron droplets might hang around by getting smaller, due to evaporation, and can carry virions to anyone nearby. So it’s not just avoiding people by distance, it’s keeping quiet! Any front row of the stalls playgoer will recognise the gentle rain of spittle as the actors perform their stuff. No wonder social gatherings are discouraged. It does seem to make it clear how vulnerable people should protect themselves and has been clear all along, from past experience of epidemics.
sicut vis videre esto
When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
Originally Posted by Ken G
Order of Kilopi
There was a fairly robust critique of that study in the Lancet, questioning its generalizability to the real world.(Many more reservations are expressed in the article, but the two above are the highlights.)First, the main assumption in the model is that dehydration is key to reducing the diameter of the expelled droplets, allowing droplets to become aerosols. The experiment was done in an environment with a relative humidity of 27%, which is below the minimum recommended indoor relative humidity of 40%. Second, the authors assumed an average viral load in saliva of 7 × 106 copies per mL on the basis of a prospective study wherein viral load was measured in sputum. Thus, they assume that viral load in sputum is the same as in saliva. The group also assume that every RNA copy detected is a potentially infectious virion, without acknowledging that in the cited study samples containing fewer than 106 copies per mL never resulted in a viable virus being isolated. An additional required proof would be to show that the viable virus is infectious and that the load is higher than the infectious dose.
The authors then made an attempt at a rebuttal, but I don't find it compelling.
Grant Hutchison
Order of Kilopi
Thanks but while aerosols are not highly effective, surely droplets are? That is the reason for masks and two metres and avoiding social contact indoors. I did not pick up that the authors suggested conversion to aerosol, only that droplets got smaller and thus fall more slowly.
sicut vis videre esto
When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
Originally Posted by Ken G
Order of Kilopi
The aerosol conversion is implicit in the abstract:(My bold.) Of course it's a continuum, but for the purposes of discussing respiratory virus transmission, the cut-off between "aerosol" and "droplet" is usually drawn at 5μm. Basically, the Lancet critique is saying that the experimental conditions that led to the 8- to 14-minute persistence do not adequately simulate what happens to speech droplets in the real world.Highly sensitive laser light scattering observations have revealed that loud speech can emit thousands of oral fluid droplets per second. In a closed, stagnant air environment, they disappear from the window of view with time constants in the range of 8 to 14 min, which corresponds to droplet nuclei of ca. 4 μm diameter, or 12- to 21-μm droplets prior to dehydration.
So the critique is very much supporting the idea that distancing is our main line of defence, and that in most enviroments we're actually not going to end up walking through an aerosol mist of infective droplets left by someone who went by ten minutes previously, speaking loudly.
Grant Hutchison
Order of Kilopi
I wish we could figure out why China has been so successful in containing the virus. They only have 3 deaths per million population. The United States and most of Europe is around 700 deaths per million.
The moment an instant lasted forever, we were destined for the leading edge of eternity.
Order of Kilopi
And what's also interesting is that it's not just China. If you look at the Pacific area in general, they are all quite low. It's like 5 for Malaysia and Singapore, and similar for New Zealand and Australia, and like 9 for South Korea and 13 for Japan. Some of it might be that there are a number of island countries, and so perhaps it didn't spread as easily between countries, and perhaps also there were better preparations due to the SARS epidemic earlier. But I agree it's a bit hard to explain.
As above, so below
Moderator
I have heard the commentary that China has not been completely honest in their reporting, but I have no evidence one way or the other.
The other thing I've heard reported is that China did very severe shutdowns for weeks at a time, and has been very strict in their enforcement of other measures.
A little googling found this article from the Lancet. What they say makes a lot of sense to me.
Despite being the first place to be hit by COVID-19, China was well-placed to tackle the disease. It has a centralised epidemic response system. Most Chinese adults remember SARS-CoV and the high mortality rate that was associated with it. “The society was very alert as to what can happen in a coronavirus outbreak”, said Xi Chen (Yale School of Public Health, New Haven, Connecticut, USA). “Other countries do not have such fresh memories of a pandemic”.“The speed of China's response was the crucial factor”, explains Gregory Poland, director of the Vaccine Research Group at the Mayo Clinic (Rochester, Minnesota, USA). “They moved very quickly to stop transmission. Other countries, even though they had much longer to prepare for the arrival of the virus, delayed their response and that meant they lost control”.Wuhan was placed under a strict lockdown that lasted 76 days. Public transport was suspended. Soon afterwards, similar measures were implemented in every city in Hubei province. Across the country, 14 000 health checkpoints were established at public transport hubs. School re-openings after the winter vacation were delayed and population movements were severely curtailed. Dozens of cities implemented family outdoor restrictions, which typically meant that only one member of each household was permitted to leave the home every couple of days to collect necessary supplies. Within weeks, China had managed to test 9 million people for SARS-CoV-2 in Wuhan. It set up an effective national system of contact tracing. By contrast, the UK's capacity for contact tracing was overwhelmed soon after the pandemic struck the country.“In China, you have a combination of a population that takes respiratory infections seriously and is willing to adopt non-pharmaceutical interventions, with a government that can put bigger constraints on individual freedoms than would be considered acceptable in most Western countries”, adds Poland. “Commitment to the greater good is engrained in the culture; there is not the hyper-individualism that characterises parts of the USA, and has driven most of the resistance to the countermeasures against the coronavirus.” Poland noted that the Chinese accept the notion that disease control is a matter of science. “China does not have the kind of raucous anti-vaccine, anti-science movement that is trying to derail the fight against COVID-19 in the USA”, he said.
Order of Kilopi
I think those are good points, but again, they don't really address why the rate is also low in Australia and New Zealand, for example, which do have typical Western societies. In their case, it might be the isolation I suppose.
Another thing that occurs to me about East Asia in general is that people tend to practice "social distancing" more than many Western countries, just culturally. You don't talk to other people in trains or to waiters in restaurants. And people don't sing together at church and funerals and that kind of thing. So there may be less of a chance for "superspreader" events, which seem to play an important role here.
As above, so below
Order of Kilopi
Yes, my impression is that in general, islands (or isolated continent in Australia's case) have done better because they can better control people entering the country. Then there is how they handled it.
China had the advantage that the outbreak was localized, and then they had a very authoritarian response that simply wouldn't work in the US and many other countries (and without getting too political, I've seen things being done even in Australia that wouldn't fly in the US and that I would personally not find acceptable unless there was a far more dangerous disease, even though I agreed with regulations here many others hated).
I think there is also a big difference in response to authority. In the US it isn't at all unusual to hear of people or groups ignoring pandemic rules.
In the US's case, we have a huge problem in that infected people were coming in from essentially every direction, arriving in many states, so there was no real way to control it. We could limit it to an extent, but unlike islands, or a country where the disease is located in one region, our control problem was far larger. Europe has had a similar problem.
I've also seen the argument that how the travel bans were handled was a big issue. When the bans went into effect, may people had to quickly return to the US. A mandatory two week quarantine on all returnees and better testing could have made a big difference. Part of the issue there is we've learned more since those days, so it might not have been so obvious at the time, nor would it have been easy to implement.
I do think if there had been a lockdown earlier and if testing had been worked out and used widely earlier, that might have made a big difference.
"The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln
I say there is an invisible elf in my backyard. How do you prove that I am wrong?
The Leif Ericson Cruiser
Order of Kilopi
Thanks, had not seen this.
The moment an instant lasted forever, we were destined for the leading edge of eternity.
Order of Kilopi
More distant culturally. Makes sense.
The moment an instant lasted forever, we were destined for the leading edge of eternity.
Order of Kilopi
How do you order food if you don't talk to the waiters?
Order of Kilopi
Sorry, I didn't mean it that strictly. I meant, don't chat with the waiters? They ask you what you want, and you place an order, but they don't come and chat with you, if that makes sense.
Actually, there are restaurants where you actually don't talk with them. You pick up an iPad and place your order, and then it comes on a conveyer belt. But that's not really the majority.
As above, so below
Order of Kilopi
It does make sense. There are huge cultural differences in the amount of interaction between diners and waiting staff in restaurants. Scotland is at the "minimal interaction" end of the scale, and I've had practical experience of the tensions that can create when Scots interact (either as waiting staff or as diners) with people from chattier cultures.
My recent excursion to a bar took the "minimal" model to "monosyllabic". We order on our phones, the server brought our order and said, "Here," as she laid the drinks on the table. We said, "Ta," and off she went. That tiny level of social interaction felt fine and appropriate, but I presume it would be harder to adopt for people from cultures in which it's customary for server and diner to discuss options endlessly and learn each other's life stories.
Grant Hutchison
Order of Kilopi
What's the deal with people who test positive for the virus, but show no symptoms? Is it that they show no symptoms YET, or do they never have any symptoms, IOW, they're already somehow immune?
Everyone is entitled to his own opinion, but not his own facts.
Order of Kilopi
Showing no symptoms is not the same as immunity. The virus can still be reproducing inside their bodies, even if their immune system is not causing obvious reactions like coughing.
"I'm planning to live forever. So far, that's working perfectly." Steven Wright
Moderator
Warning - not a doctor and didn't stay at a Holiday Inn
Assuming the test is correct (you can get false positives), I can imagine several possibilities:
- They are not showing symptoms yet
- Their body is managing the infection well, so they have the virus, but relatively few or no symptoms
- They had the symptoms, but now are mostly recovered from the disease and are just showing the residual virus
Order of Kilopi
This.
The WHO and other bodies make a contrast between presymptomatic and asymptomatic positive tests, and obviously that difference can only be determined with hindsight. The difference is important epidemiologically, because there's evidence that presymptomatic individuals can transmit the disease in the day or so before they develop symptoms, but (debated) evidence that asymptomatic individuals rarely transmit the disease. (Some of this evidence comes to the WHO from national contact tracing and surveillance efforts, and therefore hasn't passed through conventional peer review.)
Then we have a category of people who, after symptomatic or asymptomatic infection, continue to shed PCR-detectible viral RNA for a prolonged period while showing no symptoms. Doing viral cultures on these people generally shows that they are not shedding infective virions, but viral debris from dead cells.
As Noclevername says, being asymptomatic does not necessarily imply some sort of preexisting immunity. But it may do. We're still investigating what sort of immunity is important to protect against Covid, and there are conflicting reports of what happens to the "neutralizing" antibodies people produce soon after infection--the ones that prevent reinfection. Some studies have shown prolonged persistence, some have shown waning after a few months. But we know that people can retain an "immune memory", even in the absence of circulating antibodies, so that a subsequent infection is very promptly controlled, with few or no symptoms. This is certainly true of the common cold coronaviruses, so it may be true for Covid, too.
Grant Hutchison
Established Member
Hello.
I was a tad surprised to see a physicist I follow on YT, Sabine Hossenfelder, come out strongly for the Great Barrington Declaration in two of her last videos. Admittedly, I hadn't heard of Barrington, perhaps because at home we practice all the recommended measures and have not been out hunting for alternatives (or pseudoscience). However, I could use some guidance from science, thus a visit to CQ. (I tried searching for the terms but wasn't successful finding them in the thread.) Here she discusses with another physicist this growing take on how to control the outbreak.
Absent better guidance, I take the video as highly questionable, but recognize I may very well not be grasping what they are saying.
Order of Kilopi
Rather than spending time writing down what I think is naive and unethical about the Great Barrington Declaration, here's a link to the Science Media Centre, which is a great resource in these situations:
Expert reaction to Barrington Declaration.
Grant Hutchison
Moderator
Hi Hlafordlaes.
This is the wikipedia about The Great Barrington Declaration, though I found the same info on multiple other sites.
I tend to not take medical advice from economic think tanks with obvious agendas.The Great Barrington Declaration was authored by Sunetra Gupta of the University of Oxford, Jay Bhattacharya of Stanford University, and Martin Kulldorff of Harvard University.[1] The costs were paid for by the American Institute for Economic Research, a libertarian think tank that is part of a Koch-funded network of organizations associated with climate change denial.[14][15]
From later in that article is a critique of the idea from the Director of WHO which I think sums it up well.
Tedros Adhanom Ghebreyesus, the Director-General of the World Health Organization, warned against the idea of letting the virus spread in order to achieve herd immunity at an October 12 press briefing, calling the notion "unethical". He said: "Herd immunity is a concept used for vaccination, in which a population can be protected from a certain virus if a threshold of vaccination is reached … Herd immunity is achieved by protecting people from a virus, not by exposing them to it."[10][13] Tedros said that trying to achieve herd immunity by letting the virus spread unchecked would be "scientifically and ethically problematic", especially given that the long-term effects of the disease are still not fully understood.[10][13] He said that though "there has been some discussion recently about the concept of reaching so-called 'herd immunity' by letting the virus spread", "never in the history of public health has herd immunity been used as a strategy for responding to an outbreak, let alone a pandemic."[10][13][40]
Established Member
Thank you very much for the info. It is a relief, as well, to know at least the old radar still works.
Order of Kilopi
Browsing her bio, I can't see any indication that Sabine Hossenfelder has any expertise in any of the sciences necessary to understand the implications of the Great Barrington Declaration.
So I'll just email her with my take on quantum gravity and see how well that's received.
ETA: Meanwhile, we have a counterdeclaration in the form of the John Snow Memorandum, recently published in The Lancet. (Doctor John Snow is not a character from Game of Thrones--he's one of the founders of epidemiology, famous for allegedly stealing the handle off a street water pump in order to end a cholera outbreak, and also one of the founders of my own profession.)
Grant Hutchison
Last edited by grant hutchison; 2020-Oct-30 at 10:27 PM.
Order of Kilopi
Yes indeed, I am a member of the John Snow society, got the mug.
sicut vis videre esto
When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
Originally Posted by Ken G
Order of Kilopi
And they sponsor an annual Pumphandle Lecture on epidemiology.
Grant Hutchison
Order of Kilopi
Snow was a proper investigator. It was the outliers which clinched his case, where others might have dismissed them . In the famous cholera case, there was a woman who had the disease miles away in Hampstead, but had water from that pump brought to her because she liked the taste. Contemporaries believed Cholera was airborne from the smelly open drains, so Snow’s persistence was remarkable.
sicut vis videre esto
When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
Originally Posted by Ken G
Order of Kilopi
Thank you. I figured I'd get some good answers here, and you've exceeded my expectations.
Everyone is entitled to his own opinion, but not his own facts.
Order of Kilopi
Glad to have helped.
Grant Hutchison
Posting Permissions
Reply With Quote