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Thread: Disease and pandemics thread (because it's science)

  1. #1291
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    Quote Originally Posted by kzb View Post
    hmmm...Norway is way up the league table in cases per head of population, but this paper implies it would've been too cold ?
    The paper doesn't claim that epidemics are impossible outside of the claimed climatic parameters, only that vigorous community spread is less likely to establish itself--which would make control measures more effective, ceteris paribus. Watch this space, I think.

    Quote Originally Posted by kzb View Post
    Also have a question about humidity: I would've thought low humiditys was bad for a virus, because it would desiccate faster. It seems the reverse is true and that low humidity actually enhances its survival ?
    Enhances its transmission, rather. The virus can survive for hours in fine aerosols, but the droplet spray from a cough or sneeze consists of large droplets that fall out quickly, which in turn limits the range over which the virus can be spread by coughing--hence the "two metre" rule for social distancing. At low humidity, these large droplets quickly evaporate down to smaller equilibrium sizes, which stay aloft for longer, making the virus more transmissible by that route.
    There's a nice discussion (albeit a little technical) here. The same paper also discusses the way in which outdoor absolute humidity may be a surrogate measure for indoor relative humidity, linking the climatic zone observation to the reality of transmission indoors in heated spaces.

    Grant Hutchison

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    Since almost none of us in the general public are going to know the details of when a virus is going to stay airborne, maybe N95 masks are in order when we are close to people in public. That is how I feel anyways.
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

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    Quote Originally Posted by grant hutchison View Post
    The paper doesn't claim that epidemics are impossible outside of the claimed climatic parameters, only that vigorous community spread is less likely to establish itself--which would make control measures more effective, ceteris paribus. Watch this space, I think.

    Enhances its transmission, rather. The virus can survive for hours in fine aerosols, but the droplet spray from a cough or sneeze consists of large droplets that fall out quickly, which in turn limits the range over which the virus can be spread by coughing--hence the "two metre" rule for social distancing. At low humidity, these large droplets quickly evaporate down to smaller equilibrium sizes, which stay aloft for longer, making the virus more transmissible by that route.
    There's a nice discussion (albeit a little technical) here. The same paper also discusses the way in which outdoor absolute humidity may be a surrogate measure for indoor relative humidity, linking the climatic zone observation to the reality of transmission indoors in heated spaces.

    Grant Hutchison
    Never thought of that, but that's a perfectly simple explanation, thanks Grant.

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    Try and find any ! BTW, it's interesting how people go for the US standard called N95 whereas the EU standard designation nearest equivalent is P2. P3 is actually better. Can't find those either.

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    Quote Originally Posted by grant hutchison View Post
    The paper doesn't claim that epidemics are impossible outside of the claimed climatic parameters, only that vigorous community spread is less likely to establish itself--which would make control measures more effective, ceteris paribus. Watch this space, I think.

    Enhances its transmission, rather. The virus can survive for hours in fine aerosols, but the droplet spray from a cough or sneeze consists of large droplets that fall out quickly, which in turn limits the range over which the virus can be spread by coughing--hence the "two metre" rule for social distancing. At low humidity, these large droplets quickly evaporate down to smaller equilibrium sizes, which stay aloft for longer, making the virus more transmissible by that route.
    There's a nice discussion (albeit a little technical) here. The same paper also discusses the way in which outdoor absolute humidity may be a surrogate measure for indoor relative humidity, linking the climatic zone observation to the reality of transmission indoors in heated spaces.

    Grant Hutchison
    Interesting and thought stimulating. I am a coauthor in a yet unpublished study which included the comfort Of a resting human state in varied RH and Temperature. Briefly we are comfortable in most values of RH if the temperature is right, quite a narrow band of values. Part of that was examining the RH Very near surfaces; it changes because surfaces are at a different temperature and also because of seeding. RH at 80% can condense out on small particles On shiny surfaces. Of course the AH is near zero at freezing point while RH can be 100% and this can be nearly true at the low RH found indoors in winter. Outside air is heated and its RH drops. Surfaces indoors can be experiening considerable swings in RH in these conditions. Depending on whether they tend to be warmer or cooler than ambient air.
    Speculating, (that’s all it is) about the virus experience, sitting on a surface, it may prefer a particular RH for its chemistry. I would expect RH to be the variable, not AH. Its survival on droplets may be very different from that on surfaces, droplets will tend to evaporate while surfaces act as a water pump, extracting from the air RH within a boundary layer. This effect is there even in low RH air, while droplets need close to 100% RH to survive as aerosols.
    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.
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    Herd immunity rears its head again. Some interesting modelling from Oxford, which shows how sensitive our estimate of herd immunity is to the actual (and at present still poorly known) risk of severe illness for those infected. If the majority of infections are asymptomatic or unrecognized, then we could be reaching very useful levels of herd immunity already. Hence the urgent need for widespread serological testing, to get a handle on what proportion of the population has antibodies. I'd guess the current lockdowns will only come off very slowly and cautiously until that sort of information is available.
    Unfortunately, the media have latched on to this as "Oxford professor says most of us probably already immune" which is unfortunately very much not what the modelling says.

    Grant Hutchison

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    An incisive critique from Carl Bergstrom of how media (in particular the Financial Times) have misinterpreted the Oxford modelling exercise:
    Imagine if I were to write a paper about a thought experiment: "Could evolution work if animals didn't die?"
    Well, the equivalent @FT headline would read "We may be immortal—UW study."
    It's that bad.
    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    Herd immunity rears its head again. Some interesting modelling from Oxford, which shows how sensitive our estimate of herd immunity is to the actual (and at present still poorly known) risk of severe illness for those infected. If the majority of infections are asymptomatic or unrecognized, then we could be reaching very useful levels of herd immunity already. Hence the urgent need for widespread serological testing, to get a handle on what proportion of the population has antibodies. I'd guess the current lockdowns will only come off very slowly and cautiously until that sort of information is available.
    Unfortunately, the media have latched on to this as "Oxford professor says most of us probably already immune" which is unfortunately very much not what the modelling says.

    Grant Hutchison
    I like this idea.
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

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    Quote Originally Posted by grant hutchison View Post
    ... Hence the urgent need for widespread serological testing, to get a handle on what proportion of the population has antibodies. I'd guess the current lockdowns will only come off very slowly and cautiously until that sort of information is available. ...
    San Miguel County (Telluride), Colorado, has decided to serologically test every resident, about 8,000. They will treat or isolate those found with antibodies, and retest two weeks later.
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    Quote Originally Posted by Jim View Post
    San Miguel County (Telluride), Colorado, has decided to serologically test every resident, about 8,000. They will treat or isolate those found with antibodies, and retest two weeks later.
    What about visitors, and people passing through who stop at the McDonald's window? Are they blocking roads to prevent infection?
    Do good work. —Virgil Ivan "Gus" Grissom

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    Quote Originally Posted by Roger E. Moore View Post
    What about visitors, and people passing through who stop at the McDonald's window? Are they blocking roads to prevent infection?
    Test everyone within a defined area. Don't let anyone else in the perimeter unless they have been tested clear. Quarantine those who test positive.

    Keep doing this nationwide until you've cleared the whole country. Then don't let anyone in until they test clear.

    It is the only way to be sure other than nuking it from orbit.

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    Matador Security COVID-19 Update March 26 2020

    Latest developments:

    For some uplifting news that reinforces how we can all make a difference in our work and home communities click here.

    In the United States, the White House officials advised anyone who has recently traveled from the New York metropolitan area to self-quarantine for two weeks. Deborah Birx, response coordinator for the White House’s coronavirus task force, stated, “Everybody who was in New York should be self-quarantining for the next 14 days to ensure that the virus doesn't spread to others.” The New York Times has created this page depicting the states with Shelter in Place and Quarantine Orders in effect.
    Mexico's Deputy Health Minister Dr Hugo Lopez-Gatell says all non-essential activities in the country will be suspended from March 26. Mexico has reported 475 confirmed cases of coronavirus and six deaths. More details will follow when available.

    South Korea announced it will require passengers arriving from the U.S. to undergo a 14-day quarantine starting March 27. The announcement reads, “In light of the recent surge in COVID-19 cases in the United States and the rise in the number of imported cases from the US, starting March 27, a stronger screening process will be applied for inbound travelers from the United States. All symptomatic persons entering from the US, regardless of nationality, will be required to wait for testing in a facility within the airport. Persons who test positive will be transferred to a hospital or ‘Life Treatment Center’. Persons who test negative will enter self-quarantine at home for 14 days…The KCDC also advised employers to ensure that employees returning from international business trips will not return to their office for the first 2 weeks upon their return.” South Korea also says it will deny entry to people travelling from overseas who refuse to download an app that tracks their self-isolation.

    The Japanese capital of Tokyo reported more than 40 new cases of coronavirus infections for the second day running, Jiji News has reported. Tokyo Governor Yuriko Koike held an emergency news conference to warn of the risk of an explosive rise in infections, asking residents to avoid non-essential outings until April 12. The city has become the centre of Japan's coronavirus epidemic, with more than 250 cases. Japan's government is preparing to set up a special headquarters on coronavirus as early as today, in a move that could set the stage for declaring a state of emergency over the outbreak, the Kyodo news agency reported. The prime minister can declare a state of emergency if the disease is seen as posing a "grave danger" to lives and if its spread threatens the economy.

    Thailand's state of emergency came into effect on March 26. The measures will include the closure of all border crossings except to Thai nationals, diplomats and their families and people with permission to work in Thailand. The total known cases of the virus in Thailand now stands at 1,045.

    The Russian government has ordered the civil aviation authority to suspend all regular and charter flights to and from Russia from March 27, the government said on its website. Russian airlines will still be allowed to fly to other countries to bring Russian citizens back or if they are authorised by special government decisions.

    Spain's parliament has voted in favour of the government's request to extend the state of emergency - and a nationwide lockdown - by two weeks. The emergency was first declared on March 14 and includes strict stay-at-home rules. More people have died in Spain from COVID-19 than any other country except for Italy.

    For more information on the above and latest updates for your areas of interest please visit the International SOS website.

    The global number of reported infections now stands at 472,790 with 21,313 fatalities. 114,911 people are reported to have recovered, these figures are up 5,720 on yesterday.
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    Quote Originally Posted by grant hutchison View Post
    Herd immunity rears its head again. Some interesting modelling from Oxford, which shows how sensitive our estimate of herd immunity is to the actual (and at present still poorly known) risk of severe illness for those infected. If the majority of infections are asymptomatic or unrecognized, then we could be reaching very useful levels of herd immunity already. Hence the urgent need for widespread serological testing, to get a handle on what proportion of the population has antibodies. I'd guess the current lockdowns will only come off very slowly and cautiously until that sort of information is available.
    Unfortunately, the media have latched on to this as "Oxford professor says most of us probably already immune" which is unfortunately very much not what the modelling says.

    Grant Hutchison
    The Daily Mail was also saying 30% of infected don't show symptoms. They cannot differentiate between infected and on the pathway to show symptoms, and those infected who remain subclinical and uncounted.

    I believe (and I am somewhat unclear it has to be said) that almost all that 30% will eventually show symptoms. They are simply in the early stage of the pipeline. I recall a Chinese study on Wuhan which said the infected who remain uncounted as cases, and survive, is only 1%.

    I think we'd all love it if herd immunity is building more quickly than we think, but unfortunately no real evidence to back that up ?

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    My sister in Louisville, married to a doctor, now has symptoms of COVID-19. She was tested, tests not back yet. Seems to be a mild case.
    Last edited by Roger E. Moore; 2020-Mar-26 at 08:15 PM.
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    Quote Originally Posted by schlaugh View Post
    Prince Charles of the British Royal Family has tested positive for Coronavirus. The nature of his job (or that of any senior royal) means he could be a superspreader. He has gone into isolation. Apparently Camilla, Duchess of Cornwall, has not tested positive as yet.
    There was a joke about him regretting wishing for the crown. But it works better in Italian (la corona).

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    Quote Originally Posted by kzb View Post
    The Daily Mail was also saying 30% of infected don't show symptoms.
    They also had a story claiming that China had got the virus from Italy. This was because they misrepresented an Italian doctor who said it was possible that the virus had been circulating in Italy since November or December last year (based on a number of unusual cases of pneumonia that had been reported since last year) but was only identified in Februrary.

    In other words, I wouldn't take what they say with a pinch of salt, but just assume it isn't true and look for another source.
    Last edited by Strange; 2020-Mar-26 at 10:41 PM.

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    Here's a couple of thoughts/questions for kicking around (and shredding):

    i) Have these pandemics always been happening .. and our shock, now, is only because our global information technologies, only now, allow individuals to have visibility of it as it proceeds? (Eg: by online geo-tracking data, DNA/serum test result data, access to online hospital admission data, etc)?

    Have we already forgotten how we know it is even happening, because we've already become immune to knowledge of the impact access to information technologies has on humanity? (Ie: is that keyboard in front of you, right now, at the forefront of your immediate thoughts? .. I'll bet not).

    ii) Has science trivialised the likelihood of viral causes for past mass extinctions due to the lack of geologically recorded evidence? (Eg: end-Cretaceous dinosaur extinction, etc).

    I'm sure there are other science lessons to learn from all of this ..

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    Quote Originally Posted by kzb View Post
    I think we'd all love it if herd immunity is building more quickly than we think, but unfortunately no real evidence to back that up ?
    Yes, that's pretty much what I said. But the sensitivity of the herd immune proportion to the assumed infection fatality rate means that we currently have very little idea how much immunity we're generating in the population associated with each case fatality.
    The closest we've got to a hard estimate of the proportion of asymptomatic infections was the mass testing on the Diamond Princess, where it came out at about 18%. But that was a strongly bimodal population, with mainly elderly but fairly fit passengers mixed with younger crew, in a ratio of about 2:1.

    So large-scale testing of asymptomatic individuals is required, and that's already beginning to happen--Iceland is already doing it, but so far it has relatively small numbers of positive tests, and the time scale has been short, so we need to wait and see if their "50% asymptomatic" figure holds up with time and increasing numbers.

    Grant Hutchison

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    Quote Originally Posted by Strange View Post
    They also had a story claiming that China had got the virus from Italy. This was because they misrepresented an Italian doctor who said it was possible that the virus had been circulating in Italy since November or December last year (based on a number of unusual cases of pneumonia that had been reported since last year) but was only identified in Februrary.
    More on this here: https://www.reuters.com/article/us-h...-idUSKBN21D2IG

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    Pangolins... do they have the means to wipe us out? No, but...

    https://www.bbc.com/news/science-environment-52048195
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    Map of the USA with all current hotspots. The one in South Carolina is in Camden.

    https://www.cnbc.com/2020/03/26/usa-...-or-italy.html
    Do good work. —Virgil Ivan "Gus" Grissom

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    From Wired mag.
    Right now at the Mayo Clinic in Rochester, Minnesota, clinical microbiology director Elitza Theel and her team are one of the many centres undergoing the painstaking process of trying to work out which tests actually work, and which do not.

    “It is amazing how many serological assays are coming out of the woodwork,” she says. “As well as making sure that they don’t mistakenly test positive for other diseases, we’re also ensuring that they do actually recognise Covid-19. One of the challenges and delays has been just getting the kits in because of the transportation bans. There are not a lot of flights happening. We’re currently looking at one assay from the US, two from Europe and two from China. There’s a need for this, so once we identify one we think is suitable, we’ll begin offering the testing.”
    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

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    PM Boris Johnson has the coronavirus.
    https://www.bbc.co.uk/news/uk-52060791
    His advice of singing 'Happy Birthday' while washing your hands did not seem to avail him much. Still a good idea, though.

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    And Matt Hancock, the UK Health Secretary. I'm no fan of the current generation of UK politicians, of any persuasion, but there's no doubt these guys have, in their own way, been working in harm's way for a while now, by the nature of their jobs.

    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    Unfortunately, the media have latched on to this as "Oxford professor says most of us probably already immune" which is unfortunately very much not what the modelling says.
    We do need to know what fraction of those exposed acquire immunity without anyone knowing it. We do have some small samples, like when they go through a whole sports team, or congressional body, and test everyone, they get a few hits that are asymptomatic. And there are also people who have symptoms. At present, it doesn't seem like that first number greatly exceeds the second, so I've used 50% as a canonical number in all the calculations I offered earlier. It would have to be way larger than that for herd immunity to be a thing. So far, I think herd immunity is still tantamount to catastrophic failure to limit the disease, but I would love to be wrong!
    Last edited by Ken G; 2020-Mar-27 at 02:07 PM.

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    Quote Originally Posted by kzb View Post
    The Daily Mail was also saying 30% of infected don't show symptoms. They cannot differentiate between infected and on the pathway to show symptoms, and those infected who remain subclinical and uncounted.

    I believe (and I am somewhat unclear it has to be said) that almost all that 30% will eventually show symptoms. They are simply in the early stage of the pipeline. I recall a Chinese study on Wuhan which said the infected who remain uncounted as cases, and survive, is only 1%.

    I think we'd all love it if herd immunity is building more quickly than we think, but unfortunately no real evidence to back that up ?
    If Daily Fail says it, you can pretty much discount it.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Maybe next time we should let the grocers handle the pandemic response.

    … we (H-E-B) have been working on our pandemic and influenza plan for quite a while now, since 2005, when we had the threat of H5N1 ... In 2009, we actually used that plan in response to H1N1, when the swine flu came to fruition in Cibolo, and refined it, made it more of an influenza plan. We’ve continued to revise it, and it’s been a part of our preparedness plan at H-E-B ever since ...
    Inside the Story of How H-E-B Planned for the Pandemic

    Who woulda thought that anticipating and being prepared would actually work?
    Never attribute to malice that which can be adequately explained by ignorance or stupidity.
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    Just in case you had any faith in humanity remaining I just thought I'd add: since March 11, views to Wikipedia's article on the "Nibiru cataclysm" have increased by 50%.
    "Occam" is the name of the alien race that will enslave us all eventually. And they've got razors for hands. I don't know if that's true but it seems like the simplest answer."

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    Quote Originally Posted by parallaxicality View Post
    Just in case you had any faith in humanity remaining I just thought I'd add: since March 11, views to Wikipedia's article on the "Nibiru cataclysm" have increased by 50%.
    My faith is restored! I mean.... oh, forget it.
    Do good work. —Virgil Ivan "Gus" Grissom

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    A lot of places are reporting that loss of sense of smell/taste is a potential first sign of COVID-19 disease in up to half the cases. As such, it would seem prudent to check smell every morning, as a potential heads-up that self-quarantine is indicated. I have a jar of ginger to sniff.

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