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

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 Tags Coronavirus , diseases

 12th July 2020, 09:00 PM #361 TellyKNeasuss Master Poster   Join Date: Oct 2006 Posts: 2,658 I am confused about this article on a clinical trial of favipiravir in Japan. https://english.kyodonews.net/news/2...g-covid-19.htm In the study (which involved 88 patients), some of the patients (according to my understanding of the article) were given favipiravir beginning on the day they were tested positive and the remainder were given favipiravir starting on the 6th day after being tested positive. The article states that the trial failed to show that favipiravir was effective because while 2/3 of those given favipiravir beginning on the first day tested negative on the morning of the 6th day, more than half of those who weren't given it until the 6th day tested negative "by the same morning". Does this mean that they started giving favipiravir to people in the 2nd group even if they tested negative the morning that they were supposed to start using it? Or does it mean that the more than half the people in the delayed group were negative on the morning of the 6th day after they started taking favipiravir and not the 6th day after being diagnosed? And if it's the latter, why would it mean the favipiravir isn't effective just because people might recover after as many doses whether they start on it immediately or if they wait a few days? __________________ "Facts are stupid things." Ronald Reagan
 12th July 2020, 09:14 PM #362 Blue Mountain Resident Skeptical Hobbit     Join Date: Jul 2005 Location: Waging war on woo-woo in Winnipeg Posts: 6,524 Originally Posted by marting When I click on the link you provided it says I don't have sufficient permission to view it. Strange. Strange indeed. I just checked it myself and it works for me. It's in Community so you need be logged in to see it, but because you were able to post your message I assume you're logged in as well. Maybe the mods have locked you out of community? __________________ The social illusion reigns to-day upon all the heaped-up ruins of the past, and to it belongs the future. The masses have never thirsted after truth. They turn aside from evidence that is not to their taste, preferring to deify error, if error seduce them. Gustav Le Bon, The Crowd, 1895 (from the French) Canadian or living in Canada? PM me if you want an entry on the list of Canadians on the forum.
 12th July 2020, 09:25 PM #363 Ulf Nereng Muse   Join Date: Sep 2019 Location: Norway Posts: 601 Originally Posted by TellyKNeasuss I am confused about this article on a clinical trial of favipiravir in Japan. https://english.kyodonews.net/news/2...g-covid-19.htm In the study (which involved 88 patients), some of the patients (according to my understanding of the article) were given favipiravir beginning on the day they were tested positive and the remainder were given favipiravir starting on the 6th day after being tested positive. The article states that the trial failed to show that favipiravir was effective because while 2/3 of those given favipiravir beginning on the first day tested negative on the morning of the 6th day, more than half of those who weren't given it until the 6th day tested negative "by the same morning". Does this mean that they started giving favipiravir to people in the 2nd group even if they tested negative the morning that they were supposed to start using it? Or does it mean that the more than half the people in the delayed group were negative on the morning of the 6th day after they started taking favipiravir and not the 6th day after being diagnosed? And if it's the latter, why would it mean the favipiravir isn't effective just because people might recover after as many doses whether they start on it immediately or if they wait a few days? There is a difference between "failing to show that it is effective" and "showing that it is ineffective". The first group did have somewhat better results than the second, but with such small groups it wasn't enough to be called statistically significant. They probably only gave the 2nd group the treatment to those who still tested positive. It would be better if we could see the actual research paper instead of a news story, but it may not have passed peer review yet. Last edited by Ulf Nereng; 12th July 2020 at 09:26 PM.
 12th July 2020, 10:58 PM #364 Puppycow Penultimate Amazing     Join Date: Jan 2003 Location: Yokohama, Japan Posts: 25,904 Originally Posted by TellyKNeasuss I am confused about this article on a clinical trial of favipiravir in Japan. https://english.kyodonews.net/news/2...g-covid-19.htm In the study (which involved 88 patients), some of the patients (according to my understanding of the article) were given favipiravir beginning on the day they were tested positive and the remainder were given favipiravir starting on the 6th day after being tested positive. The article states that the trial failed to show that favipiravir was effective because while 2/3 of those given favipiravir beginning on the first day tested negative on the morning of the 6th day, more than half of those who weren't given it until the 6th day tested negative "by the same morning". Does this mean that they started giving favipiravir to people in the 2nd group even if they tested negative the morning that they were supposed to start using it? Or does it mean that the more than half the people in the delayed group were negative on the morning of the 6th day after they started taking favipiravir and not the 6th day after being diagnosed? And if it's the latter, why would it mean the favipiravir isn't effective just because people might recover after as many doses whether they start on it immediately or if they wait a few days? Originally Posted by Ulf Nereng There is a difference between "failing to show that it is effective" and "showing that it is ineffective". The first group did have somewhat better results than the second, but with such small groups it wasn't enough to be called statistically significant. They probably only gave the 2nd group the treatment to those who still tested positive. It would be better if we could see the actual research paper instead of a news story, but it may not have passed peer review yet. 88 patients is a rather small sample size. Another story: https://mainichi.jp/english/articles...0m/0fe/107000c Quote: Of those who had Avigan administered from the first day, 66.7 percent saw the virus disappear by the morning of the sixth day, while 56.1 percent of those with delayed doses showed similar signs of recovery by the same morning. It took an average 2.1 days and 3.2 days for the first and second groups to have their fevers lower, respectively, the university said. As Avigan can inhibit the replication of the virus in cells, experts say it may bring about improvements in patients but it cannot be administered to expectant mothers or women who are likely to become pregnant as it may cause birth defects. I wonder how they define "women who are likely to become pregnant". All women of reproductive age or those actively trying to get pregnant? Anyway, Ulf is right: The study doesn't mean that the drug doesn't work, only that the p value didn't reach the level of statistical significance. A larger study with more patients might have. Or the differences might only be due to random noise. But it sort of hints that there might be a small effect there, albeit the confidence level is less than 95%. __________________ A fool thinks himself to be wise, but a wise man knows himself to be a fool. William Shakespeare
 13th July 2020, 12:00 AM #365 Ulf Nereng Muse   Join Date: Sep 2019 Location: Norway Posts: 601 Originally Posted by Puppycow I wonder how they define "women who are likely to become pregnant". All women of reproductive age or those actively trying to get pregnant? Anyway, Ulf is right: The study doesn't mean that the drug doesn't work, only that the p value didn't reach the level of statistical significance. A larger study with more patients might have. Or the differences might only be due to random noise. But it sort of hints that there might be a small effect there, albeit the confidence level is less than 95%. Surely they must mean the pretty ones!
 13th July 2020, 12:23 AM #366 Puppycow Penultimate Amazing     Join Date: Jan 2003 Location: Yokohama, Japan Posts: 25,904 Originally Posted by Ulf Nereng Surely they must mean the pretty ones! But seriously though, this is Japan. Birth control pills weren't legalized here until 1999, and they still aren't covered by insurance. I'm wondering what their criteria are for deciding whether a given woman is "likely to become pregnant". Marital status? Age? Something tells me they don't simply take a woman's word for it. But I could be wrong about that. __________________ A fool thinks himself to be wise, but a wise man knows himself to be a fool. William Shakespeare
 13th July 2020, 01:36 AM #367 rjh01 Gentleman of leisure Tagger     Join Date: May 2005 Location: Flying around in the sky Posts: 26,638 Here is something really stupid. How would you like to go to a party with the INTENTION of catching the virus? Just to prove to yourself it is real. These parties exist. Here is one example https://www.theguardian.com/world/20...id-party-texas People are dying due to this stupidity. Plus the virus is spreading even more. __________________ This signature is for rent.
 13th July 2020, 02:20 AM #369 Darat Lackey Administrator     Join Date: Aug 2001 Location: South East, UK Posts: 97,844 Originally Posted by Puppycow But seriously though, this is Japan. Birth control pills weren't legalized here until 1999, and they still aren't covered by insurance. I'm wondering what their criteria are for deciding whether a given woman is "likely to become pregnant". Marital status? Age? Something tells me they don't simply take a woman's word for it. But I could be wrong about that. It's usually sexually active and pre menopause. __________________ I wish I knew how to quit you
 13th July 2020, 02:24 AM #370 Orphia Nay Penguilicious Spodmaster.Tagger     Join Date: May 2005 Location: Ponylandistan Presidential Palace (above the Spods' stables). Posts: 38,806 Originally Posted by The Atheist Appears to be definite evidence of asymptomatic transmission here: https://www.stuff.co.nz/national/hea...person-cluster Indeed. They keep talking about "shedding" and then there's this: https://pbs.twimg.com/media/Ebd7M2SX...name=4096x4096 Talking would do enough to infect others in a lift. Originally Posted by The Atheist Yeah, I thought that was interesting, because it ties in with a position from months back that the reason the elderly might be more likely to die while kids get nothing, is down to having had a cold more recently. Needs more work. I'm not sure whether that "expect" in the first sentence shouldn't be "hope". Definitely speculative, because it doesn't work that way for at least some other ssRNA viruses. Indeed, speculative. We just don't know. I hope or speculate that perhaps some people are closer to knowing than I fear. __________________ "We stigmatize and send to the margins people who trigger in us the feelings we want to avoid" - Melinda Gates, "The Moment of Lift".
 13th July 2020, 04:51 AM #371 TellyKNeasuss Master Poster   Join Date: Oct 2006 Posts: 2,658 Originally Posted by Puppycow 88 patients is a rather small sample size. It seems like no one can advance beyond small trials. With 400,000 people a week getting infected just in the US, it would seem that there should be a large pool of available patients for trials. __________________ "Facts are stupid things." Ronald Reagan
 13th July 2020, 05:09 AM #372 TellyKNeasuss Master Poster   Join Date: Oct 2006 Posts: 2,658 Deleted __________________ "Facts are stupid things." Ronald Reagan Last edited by TellyKNeasuss; 13th July 2020 at 05:11 AM.
 13th July 2020, 10:20 AM #373 Chris_Halkides Penultimate Amazing     Join Date: Dec 2009 Posts: 10,049 favipiravir mechanism of action A 2020 article on favipiravir included the following passage: "Acyclovir causes chain termination at the incorporated site during the elongation of herpes simplex virus and varicella-zoster virus DNA and prevents viral DNA synthesis. However, the incorporated acyclovir is removed by the proofreading activity of viral DNA polymerase, and viral DNA elongation continues." It seems that favipiravir is a chain terminator and that it has a distinct mode of action versus ribavirin. From my quick skim of this article, it is not yet clear to me whether or not favipiravir is removed by a corresponding proofreading 3'-5'-exoribonuclease activity (ExoN) in coronaviruses. I will try to read up on it a bit more in the following days. __________________ It is possible both to be right about an issue and to take oneself a little too seriously, but I would rather be reminded of that by a friend than a foe. (a tip of the hat to Foolmewunz)
 13th July 2020, 10:22 AM #374 Belz... Fiend God     Join Date: Oct 2005 Location: In a post-fact world Posts: 92,201 Originally Posted by Puppycow From Scientific American: Mounting Evidence Suggests Coronavirus Is Airborne—but Health Advice Has Not Caught Up (July 8, 2020) Haven't we known this for months? I mean, that's the whole point of masks and distancing. __________________ Master of the Shining Darkness "My views are nonsense. So what?" - BobTheCoward
 13th July 2020, 10:25 AM #375 Belz... Fiend God     Join Date: Oct 2005 Location: In a post-fact world Posts: 92,201 Originally Posted by Steve What about those who are perceived as recovered? Do they have a bunch of undetected clots that could wreak havoc at any time? Scary thought. A very pertinent and scary question. __________________ Master of the Shining Darkness "My views are nonsense. So what?" - BobTheCoward
 13th July 2020, 10:32 AM #376 Belz... Fiend God     Join Date: Oct 2005 Location: In a post-fact world Posts: 92,201 Originally Posted by rjh01 Here is something really stupid. How would you like to go to a party with the INTENTION of catching the virus? Just to prove to yourself it is real. These parties exist. Here is one example https://www.theguardian.com/world/20...id-party-texas People are dying due to this stupidity. Plus the virus is spreading even more. Worse. A party with the intention of infecting others. That should be criminal. __________________ Master of the Shining Darkness "My views are nonsense. So what?" - BobTheCoward
 13th July 2020, 11:09 AM #377 The Atheist The Grammar Tyrant     Join Date: Jul 2006 Posts: 28,602 Two interesting pieces of research out today: School children found to have very low rates of infection, to the extent that one researcher suggests schools might even prove to be a brake on infections: https://www.theguardian.com/world/20...schools-saxony Still needs more work, but the evidence appears to be stacking up. And air pollution again identified as having a very strong relationship to negative outcomes: https://www.theguardian.com/world/20...onavirus-study That seems to fit into the Captain Obvious area of research, being exactly what you'd expect to see. __________________ The point of equilibrium has passed; satire and current events are now indistinguishable.
 13th July 2020, 11:17 AM #378 Myriad The Clarity Is Devastating     Join Date: Nov 2006 Location: Betwixt Posts: 17,636 Originally Posted by rjh01 Here is something really stupid. How would you like to go to a party with the INTENTION of catching the virus? Just to prove to yourself it is real. These parties exist. Here is one example https://www.theguardian.com/world/20...id-party-texas I have my doubts about the reality or at least the accuracy of this story. The only source for it is a video by a doctor at Methodist Hospital in San Antonio, who says she "heard about" the case. Of course the hospital wouldn't be allowed to release the man's name, but there's been nothing from any family member, anyone who actually provided care for the man (including the nurse who heard his last words), nor anyone else who attended the alleged party. The account sounds more like a moral fable than an actual course of events (though it could turn out to be both). __________________ A zømbie once bit my sister...
 13th July 2020, 11:52 AM #379 dann Penultimate Amazing   Join Date: Feb 2004 Posts: 13,936 Originally Posted by rjh01 Here is something really stupid. How would you like to go to a party with the INTENTION of catching the virus? Just to prove to yourself it is real. These parties exist. Here is one example https://www.theguardian.com/world/20...id-party-texas People are dying due to this stupidity. Plus the virus is spreading even more. I came up with something similar four months ago when I still thought it sounded like a good idea: COVID-19 Party - A Modest Proposal. I guess I should have trade marked it. Based on what we know now about how it can make even some young people seriously ill, I wouldn't attempt it even if I were what I back then considered to be the right age. However, at this point some parties might as well be regular Covid-19 parties: Efter stigende smittetal: Regeringen lukker Bulgariens indendørs barer og diskoteker (DR.dk, July 9, 2020) After rising number of infections: The government locks down Bulgaria's indoor bars and discos __________________ /dann "Stupidity renders itself invisible by assuming very large proportions. Completely unreasonable claims are irrefutable. Ni-en-leh pointed out that a philosopher might get into trouble by claiming that two times two makes five, but he does not risk much by claiming that two times two makes shoe polish." B. Brecht "The abolition of religion as the illusory happiness of the people is required for their real happiness. The demand to give up the illusion about its condition is the demand to give up a condition which needs illusions." K. Marx Last edited by dann; 13th July 2020 at 11:54 AM.
 13th July 2020, 11:56 AM #380 marting Master Poster     Join Date: Sep 2003 Posts: 2,264 Originally Posted by Myriad I have my doubts about the reality or at least the accuracy of this story. The only source for it is a video by a doctor at Methodist Hospital in San Antonio, who says she "heard about" the case. Of course the hospital wouldn't be allowed to release the man's name, but there's been nothing from any family member, anyone who actually provided care for the man (including the nurse who heard his last words), nor anyone else who attended the alleged party. The account sounds more like a moral fable than an actual course of events (though it could turn out to be both). Quite possibly a moral fable. People often spread fables if they believe it will improve execrable behavior. But if proven to be false it can then encourage the behavior. https://www.nytimes.com/2020/05/06/u...d-parties.html Quote: County health officials in Washington State walked back earlier claims that young people were gathering in a deliberate attempt to be exposed to the coronavirus. __________________ Flying's easy. Walking on water, now that's cool.
 13th July 2020, 01:10 PM #381 Myriad The Clarity Is Devastating     Join Date: Nov 2006 Location: Betwixt Posts: 17,636 Originally Posted by marting Quite possibly a moral fable. People often spread fables if they believe it will improve execrable behavior. But if proven to be false it can then encourage the behavior. https://www.nytimes.com/2020/05/06/u...d-parties.html Regarding the Times story, even though the Washington state health officials retracted the claim, I can see the logic (and the risk) in "let's get exposed and get it over with" arrangements (including in "party" form) for young low-medical-risk people. I predicted this myself a few months ago. Of course, if the young people who do that don't quarantine themselves afterward it goes from understandable to sociopathic in my estimation, and more recent findings of potential long term effects even for mild cases bumps the risk higher than I would have estimated back then. But still, people making an assessment of "I stand to risk X and gain Y" is plausible enough. The hard part would be the logistics. How do you find someone who's tested positive (or else you're more likely to catch some other crud from them), symptomatic (or else you don't really know whether they're contagious), and feels good enough to host or attend a party? "I went to a Covid party hosted by a Covid-infected person because I thought Covid was a hoax" is, by contrast, simply incoherent. If you don't believe the disease exists or can be transmitted, why go to an event with that ostensible purpose? Or if you're just going to the party to have fun, disregarding the risk of Covid, why call it a Covid party? The closest it comes to making sense is if you interpret it as, "I thought the risk of getting a severe case if you're under 40 was a hoax," along with the previous idea of getting infected to get it over with. __________________ A zømbie once bit my sister...
 13th July 2020, 01:36 PM #382 The Atheist The Grammar Tyrant     Join Date: Jul 2006 Posts: 28,602 Uh-oh. That "can you catch Covid again" question may have been answered in the positive. https://www.vox.com/platform/amp/202...-herd-immunity tl;dr version: Guy has mild Covid, recovers & tests negative twice. Then gets a bad dose, requiring multiple hospital visits. This would be unbelievably bad news for a second wave, considering the overwhelming majority of people having a very mild/asymptomatic dose in the first wave. Those shades of 1918 just went up a notch. __________________ The point of equilibrium has passed; satire and current events are now indistinguishable.
 13th July 2020, 02:14 PM #383 marting Master Poster     Join Date: Sep 2003 Posts: 2,264 California has a listing of different models along with description and links to raw data and often, computer code. Nice! https://calcat.covid19.ca.gov/cacovidmodels/ __________________ Flying's easy. Walking on water, now that's cool.
 13th July 2020, 02:53 PM #384 arthwollipot Observer of PhenomenaPronouns: he/him     Join Date: Feb 2005 Location: Ngunnawal Country Posts: 71,089 Originally Posted by Belz... Haven't we known this for months? I mean, that's the whole point of masks and distancing. Yes, but the new information here is that the virus can be transmitted not only via large droplets, which fall quickly and against which distancing generally protects, but also via very tiny aerosolised droplets, which can hang in the air for potentially a very long time - up to 2 hours is the timeframe that I have seen on various sources. There was speculation as to whether this might be the case a couple of months ago, but now I believe that there is evidence. __________________ We will meet them on the beach, we will meet them on the phone hook-ups. - Scott Morrison, probably
 13th July 2020, 03:12 PM #385 casebro Penultimate Amazing     Join Date: Jun 2005 Posts: 18,750 Originally Posted by arthwollipot Yes, but the new information here is that the virus can be transmitted not only via large droplets, which fall quickly and against which distancing generally protects, but also via very tiny aerosolised droplets, which can hang in the air for potentially a very long time - up to 2 hours is the timeframe that I have seen on various sources. There was speculation as to whether this might be the case a couple of months ago, but now I believe that there is evidence. If all these "could survive,,," and "could be transmitted..." were true, wouldn't we all be dead by now? We need some kind of R value for theoretical methods of transmission. Top- crowded work and living conditions, 100. Grocery store cart handles, .000002 Isn't that the kind of stuff to expect from epidemiologists? __________________ Any sufficiently advanced idea is indistinguishable from idiocy to those who don't actually understanding the concept.
 13th July 2020, 03:16 PM #386 Blue Mountain Resident Skeptical Hobbit     Join Date: Jul 2005 Location: Waging war on woo-woo in Winnipeg Posts: 6,524 Originally Posted by The Atheist Uh-oh. That "can you catch Covid again" question may have been answered in the positive. https://www.vox.com/platform/amp/202...-herd-immunity tl;dr version: Guy has mild Covid, recovers & tests negative twice. Then gets a bad dose, requiring multiple hospital visits. This would be unbelievably bad news for a second wave, considering the overwhelming majority of people having a very mild/asymptomatic dose in the first wave. Those shades of 1918 just went up a notch. Thank you for providing the "TL;DR" version! It provides context to the raw link, which is the primary goal of the campaign for good linking. __________________ The social illusion reigns to-day upon all the heaped-up ruins of the past, and to it belongs the future. The masses have never thirsted after truth. They turn aside from evidence that is not to their taste, preferring to deify error, if error seduce them. Gustav Le Bon, The Crowd, 1895 (from the French) Canadian or living in Canada? PM me if you want an entry on the list of Canadians on the forum.
 13th July 2020, 03:46 PM #387 arthwollipot Observer of PhenomenaPronouns: he/him     Join Date: Feb 2005 Location: Ngunnawal Country Posts: 71,089 Originally Posted by casebro If all these "could survive,,," and "could be transmitted..." were true, wouldn't we all be dead by now? We need some kind of R value for theoretical methods of transmission. Top- crowded work and living conditions, 100. Grocery store cart handles, .000002 Isn't that the kind of stuff to expect from epidemiologists? Yeah. You're welcome to search for that information rather than relying on my vague memory. __________________ We will meet them on the beach, we will meet them on the phone hook-ups. - Scott Morrison, probably
 13th July 2020, 06:29 PM #388 Puppycow Penultimate Amazing     Join Date: Jan 2003 Location: Yokohama, Japan Posts: 25,904 Originally Posted by Myriad "I went to a Covid party hosted by a Covid-infected person because I thought Covid was a hoax" is, by contrast, simply incoherent. If you don't believe the disease exists or can be transmitted, why go to an event with that ostensible purpose? Or if you're just going to the party to have fun, disregarding the risk of Covid, why call it a Covid party? The closest it comes to making sense is if you interpret it as, "I thought the risk of getting a severe case if you're under 40 was a hoax," along with the previous idea of getting infected to get it over with. To mock the hoax. Remember when James Randi would "overdose" on homeopathic pills? __________________ A fool thinks himself to be wise, but a wise man knows himself to be a fool. William Shakespeare
 13th July 2020, 07:14 PM #389 Skeptic Ginger Nasty Woman     Join Date: Feb 2005 Posts: 87,909 Originally Posted by The Atheist Uh-oh. That "can you catch Covid again" question may have been answered in the positive. https://www.vox.com/platform/amp/202...-herd-immunity tl;dr version: Guy has mild Covid, recovers & tests negative twice. Then gets a bad dose, requiring multiple hospital visits. This would be unbelievably bad news for a second wave, considering the overwhelming majority of people having a very mild/asymptomatic dose in the first wave. Those shades of 1918 just went up a notch. There's no evidence, only an attempt to explain someone having negative tests followed by positive tests. Until the virus of the initial infection is genetically analyzed and found to be different from the second infection, don't put too much stock in these stories, even if it is a doctor making the assertion. These are usually considered failure to clear the virus rather than a reinfection.
 13th July 2020, 07:16 PM #390 Skeptic Ginger Nasty Woman     Join Date: Feb 2005 Posts: 87,909 Originally Posted by arthwollipot Yes, but the new information here is that the virus can be transmitted not only via large droplets, which fall quickly and against which distancing generally protects, but also via very tiny aerosolised droplets, which can hang in the air for potentially a very long time - up to 2 hours is the timeframe that I have seen on various sources. There was speculation as to whether this might be the case a couple of months ago, but now I believe that there is evidence. There was evidence quite a while ago. This is the WHO and the CDC barely coming around officially. Give it a couple of weeks and people will collectively remember we have always been at war with Eurasia. Last edited by Skeptic Ginger; 13th July 2020 at 07:19 PM.
 13th July 2020, 07:52 PM #391 marting Master Poster     Join Date: Sep 2003 Posts: 2,264 Originally Posted by The Atheist Uh-oh. That "can you catch Covid again" question may have been answered in the positive. https://www.vox.com/platform/amp/202...-herd-immunity tl;dr version: Guy has mild Covid, recovers & tests negative twice. Then gets a bad dose, requiring multiple hospital visits. This would be unbelievably bad news for a second wave, considering the overwhelming majority of people having a very mild/asymptomatic dose in the first wave. Those shades of 1918 just went up a notch. Looked at an interesting paper from a link in the VOX piece: Longitudinal evaluation and decline of antibody responses in SARS-CoV-2 infection https://www.medrxiv.org/content/10.1...429v1.full.pdf There is a pretty large antibody decline after 90 days that is more in line with the endemic cold coronavirus than SARS or MERS which declined after a few years. Not good. Another factor of major significance is that antibody tests may not be counting lots of people infected more than 2 months earlier. This would mean that the percentage of the population that is actually infected may be significantly larger than sero estimates suggest. This suggests a somewhat lower IFR OTOH it's a problem for vaccines and herd immunity which won't occur w/o long lasting immunity and vaccines. But this doesn't mean vaccines may not be very effective or long lasting since this isn't yet known. It's just a bad sign. It will make determining the efficacy of a vaccine quite a bit harder as they will have to wait quite a while to see if a vaccine candidate is actually providing anything other than a short term protection. Worse, there is a significant possibility that Covid-19 will become an endemic virus. __________________ Flying's easy. Walking on water, now that's cool.
 13th July 2020, 07:58 PM #392 rjh01 Gentleman of leisure Tagger     Join Date: May 2005 Location: Flying around in the sky Posts: 26,638 Originally Posted by Skeptic Ginger There's no evidence, only an attempt to explain someone having negative tests followed by positive tests. Until the virus of the initial infection is genetically analyzed and found to be different from the second infection, don't put too much stock in these stories, even if it is a doctor making the assertion. These are usually considered failure to clear the virus rather than a reinfection. That is even worse. The positive results were 3 months apart! That would mean that Covid 19 is a chronic illness. It would also mean that after Australia clears everyone from the virus it could spontaneously reappear, not from overseas but from these cases. __________________ This signature is for rent.
 13th July 2020, 08:31 PM #393 Puppycow Penultimate Amazing     Join Date: Jan 2003 Location: Yokohama, Japan Posts: 25,904 Originally Posted by The Atheist Uh-oh. That "can you catch Covid again" question may have been answered in the positive. https://www.vox.com/platform/amp/202...-herd-immunity tl;dr version: Guy has mild Covid, recovers & tests negative twice. Then gets a bad dose, requiring multiple hospital visits. This would be unbelievably bad news for a second wave, considering the overwhelming majority of people having a very mild/asymptomatic dose in the first wave. Those shades of 1918 just went up a notch. Makes you wonder whether a vaccine will work. Possibly the first time he had it, it was a false positive and he actually just had a cold? False positives seem to occur with PCR tests. About 2% of the time on average. What Zebra Mussels Can Tell Us About Errors In Coronavirus Tests (NPR) Quote: Cohen discovered that false positives were actually fairly common. The best labs reported few if any, but other labs reported up to 8% of their positive results were false positives. The average was around 2% false positive. If false positives are actually happening in mild cases, you could get a "reinfection" because the first time was actually only a false positive. __________________ A fool thinks himself to be wise, but a wise man knows himself to be a fool. William Shakespeare
 13th July 2020, 08:56 PM #394 marting Master Poster     Join Date: Sep 2003 Posts: 2,264 Nearly everything is shut down in California that is inside and some things outside. With one big exception: Indian Casinos. They closed in the first wave but are staying open now. For instance: Barona, in San Diego __________________ Flying's easy. Walking on water, now that's cool.
 13th July 2020, 09:09 PM #395 Puppycow Penultimate Amazing     Join Date: Jan 2003 Location: Yokohama, Japan Posts: 25,904 Originally Posted by Puppycow False positives seem to occur with PCR tests. About 2% of the time on average. I just want to add a little bit more to this for clarification after reading more. A false positive rate of 2% does not mean that 2% of all positive results are false positives, it means that 2% of all tests conducted (both positive and negative) are false positives. What this means in practice is that, if say the true rate is 8% and the false positive rate of 2%, then 20% of all positive results are false positives. The lower the true rate is, the greater the proportion of positive results will be false positives. So out of say, 10,000 positive tests (out of 100,000 total tests given), 2,000 of those may be false positives. Given that, the scenario where someone gets "reinfected" because of a false positive test seems quite likely to occur given enough tests conducted. __________________ A fool thinks himself to be wise, but a wise man knows himself to be a fool. William Shakespeare
 13th July 2020, 09:11 PM #396 Puppycow Penultimate Amazing     Join Date: Jan 2003 Location: Yokohama, Japan Posts: 25,904 Originally Posted by marting Nearly everything is shut down in California that is inside and some things outside. With one big exception: Indian Casinos. They closed in the first wave but are staying open now. For instance: Barona, in San Diego The governor of California has no authority to shut them down? (Supposedly tribal governments are "sovereign" aren't they? Or "autonomous". Not sure what the right word is.) __________________ A fool thinks himself to be wise, but a wise man knows himself to be a fool. William Shakespeare
 14th July 2020, 10:17 AM #397 GodMark2 Master Poster     Join Date: Oct 2005 Location: Oregon, USA Posts: 2,211 Originally Posted by Puppycow I just want to add a little bit more to this for clarification after reading more. A false positive rate of 2% does not mean that 2% of all positive results are false positives, it means that 2% of all tests conducted (both positive and negative) are false positives. What this means in practice is that, if say the true rate is 8% and the false positive rate of 2%, then 20% of all positive results are false positives. The lower the true rate is, the greater the proportion of positive results will be false positives. So out of say, 10,000 positive tests (out of 100,000 total tests given), 2,000 of those may be false positives. Given that, the scenario where someone gets "reinfected" because of a false positive test seems quite likely to occur given enough tests conducted. According to Wikipedia, you are exactly incorrect. False positive rateWP Quote: The false positive rate is ${\displaystyle {\frac {\mathrm {FP} }{N}}={\frac {\mathrm {FP} }{\mathrm {FP} +\mathrm {TN} }}}$ where ${\displaystyle \mathrm {FP} }$ is the number of false positives, ${\displaystyle \mathrm {TN} }$ is the number of true negatives and ${\displaystyle N=\mathrm {FP} +\mathrm {TN} }$ is the total number of negatives. This would go a long way toward explaining many misunderstandings earlier. __________________ Knowing that we do not know, it does not necessarily follow that we can not know. Last edited by GodMark2; 14th July 2020 at 10:19 AM. Reason: copy/past errrrror
 14th July 2020, 10:25 AM #398 chrispy Graduate Poster     Join Date: Oct 2013 Location: Solola, Guatemala Posts: 1,097 Well, we finally had our first positive in my itty-bitty mountain town in Guatemala. A police officer from the city gave it to his mom whilst visiting her. Now she and 5 family members are in 3 week guarded quarantine. It was only a matter of time, but it is here now. We had it pretty easy. I hope it doesn't spread. The health care in my town is pretty much nonexistent. We have only one doctor that I would consider to be even 'good' and several thag are 'meh', as well as one fake doctor who lies about her credentials, experience, and education. We have no hospital, just small independent clinics. __________________ Just a spec in the Spectrum... Last edited by chrispy; 14th July 2020 at 10:27 AM.
 14th July 2020, 10:43 AM #399 marting Master Poster     Join Date: Sep 2003 Posts: 2,264 Originally Posted by GodMark2 According to Wikipedia, you are exactly incorrect. False positive rateWP This would go a long way toward explaining many misunderstandings earlier. Seems to me the difference between the expected value of 1840 (by calculation assuming TFN rate=0 as it's not given) and the 2000 false negatives in Puppycow's example is quibbling. IE: 18.4% v 20%. __________________ Flying's easy. Walking on water, now that's cool. Last edited by marting; 14th July 2020 at 10:46 AM.
 14th July 2020, 11:44 AM #400 The Atheist The Grammar Tyrant     Join Date: Jul 2006 Posts: 28,602 Originally Posted by marting Worse, there is a significant possibility that Covid-19 will become an endemic virus. Well, there would be one upside to that - pension costs will be slashed. Originally Posted by Puppycow If false positives are actually happening in mild cases, you could get a "reinfection" because the first time was actually only a false positive. And to put that into perspective, when the world is conducting millions of tests a day, small percentages add up to big numbers. __________________ The point of equilibrium has passed; satire and current events are now indistinguishable.

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