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About Jason

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  • Birthday November 22

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  1. The bulk of evidence indicates that true re-infections are rare and that most people develop at least short-term immunity. I don't think news of these re-infections is inherently bad news for the effectiveness of a vaccine. Of course, the short incubation time of the virus and moderate mutation rate are strongly suggestive that any vaccine won't offer permanent protection, but that was already known. That's not actually herd immunity. Herd immunity is when chains of transmission come to a halt altogether because of a lack of susceptible individuals. The mildness of modern OC43 is also almost certainly not a result of natural selection on humans. It's much more likely because once transmission in human populations slows because of a large number of immune individuals, milder strains of the virus can propagate more effectively, and they outcompete more severe strains. Not quite SOP. It's more common to rely on natural infection, exceptions are mild diseases, ones for which there is an effective treatment, or when comparing a new vaccine to an older one known to be effective. I think COVID-19 is in a bit of a gray zone for the first two qualifications at this point. (Regardless, it's understandable why a human challenge trial is being pursued, and they're taking precautions and seeking informed consent etc.)
  2. So. Over in other thread, someone predicted Giuliani is toast. Call me a cynic but I don't think so? Like, maybe he'll be toast after the election (god willing), but I can't see Trump dumping him over this. That said, definitely not going to help his credibility with regards to the Biden stuff. Not that he had much to begin with of course.
  3. To expand on this point, I think it's almost certainly not how the virus is effected by the weather that drives the apparent seasonality, but rather how the virus shapes human behaviour. It's worth noting that the US actually had a big spike in transmission in the hottest part summer in the southeast where people tend to flee the heat by going indoors to air-conditioned environments. At that same time, in the northern US where people tend to go outside in the summer after hibernating in the winter, the virus waned. Now that the weather is getting lousy in the north but it's nice and comfortable outside in the south, the pattern is reversing. Anything that causes people to spend more time indoors and with less ventilation (closed windows etc.) is going to increase transmission, and vice versa.
  4. It's a good article, one I had actually bookmarked already before you tagged me here. It's consistent with articles I've read elsewhere, and I've also previously seen some of the cited sources. Undoubtedly, a huge part of Japan's success in controlling COVID-19 has been in nearly eliminating the superspreader events that are responsible for ~80% or more of the spread. So in theory, just by avoiding superspreader events you can keep R around or below 1. It's worth noting that Japan has neither had a lockdown (the state of emergency was voluntary and did not involve widespread business closure) nor does it have the thorough testing/tracing/isolation programs implemented by its East Asian neighbours. There's a part of the article I want to draw attention to, especially with regard to movie theatres: Many people together is certainly a necessary condition for superspreading (by definition), and an indoor setting and not wearing masks are almost certainly necessary conditions as well. To my knowledge, there are no counterexamples - superspreader events that have occurred either outdoors, or indoors with full mask compliance. The lack of superspreader events in indoor environments with full mask compliance has actually been quite notable. A definition for "prolonged contact" is hard to pin down, but basically transmissions don't occur if you've had less that 10-15 minutes contact, and after that the longer the contact, the higher the risk of transmission. "Many people indoors not wearing masks with prolonged contact" is may also be sufficient for a super-spreader event, but I strongly suspect another important factor is vocalization. Another common feature of the documented superspreader events is that they involve talking and/or singing. This isn't surprising; it's known that talking releases about ten times as many respiratory droplets compared to breathing. Movie theatres certainly meet the conditions of "many people indoors with prolonged contact". In theory, they need not meet the condition of "not wearing masks", if a mask-wearing policy were enforced. Of course, concessions would need to be banned, and that combined with reduced capacity might mean theatres wouldn't be profitable. There's definitely variation in expert opinion about how risky theatres are, which makes sense because you can reasonably give the aforementioned factors different weighting, and also make different assumptions about mask compliance, concessions, ventilation etc. The ultimate authority in my view is empirical evidence, but of course the problem there is that we may not have any applicable evidence to review. Taiwan has effectively eliminated the virus, and SK, China, and Vietnam very nearly so. Japan hasn't eliminated the virus, but has an extraordinarily high degree of mask compliance, so the lack of superspreader events in movie theatres there may not mean anything for us. Canada and other non-US Western countries had a period where movie attendance was decent (Tenet), but there isn't much in the way of publicly available data for contact tracing. The public health authorities here are telling us that half of traced cases are coming from bars and restaurants, but that's about it - they don't tell us which establishments, nor about the rest of traced cases. I do know that cinemas have been added to the list of businesses that are being closed back down in response to our cases rising, but I don't know if that's based on perceived risk or on probable transmissions we're not being told about. I guess in conclusion what it comes down to is that even though movie theatres aren't a main driver of superspreader events - that'd be social gatherings, bars, and indoor dining - they're probably going to be a casualty of the insufficient number of citizens in (at least most) Western countries willing to commit to wearing masks indoors, and consequently to sacrifice indoor activites that conflict with mask wearing.
  5. My only other idea is to save the video as an mp4, then upload to youtube or something.
  6. Test: @chasmmi Can confirm this video is very resistant to being embedded here,
  7. Seroprevalence studies done in April/May were probably quite accurate generally speaking, they showed that the tests correctly identified PCR-positive individuals >90% of the time. PCR-positive individuals testing negative on antibody tests tends to be an issue >2 months after infection. That might be part of the problem for this Italian study, but I don't think it's the entire issue. Individuals testing negative after a few months seem to be around 30% or less, and I think the Italian study is underestimating prevalence by about 50%, based on the IFR and the fact that the Lombardy subsample was only at 7.5%. Previous studies in Lombardy measured seroprevalence around 13-15%.
  8. It is. It may be that for whatever reason people aren't reporting those comments. I know I declined to report his previous comment because I decided it would be better to address it. And yes, suggesting 1 billion worldwide infections is absurd. Even if you assume that half of the COVID deaths worldwide are being missed (almost certainly an overestimate), that would put us at about 1.4M deaths. And even using a low IFR of 0.5% (it's probably closer to 1%), that would result in about ~300M infections. But that is towards the upper range of plausibility, it's not probable.
  9. Sweden's outbreak is under control now but I can't find any evidence to support that it's a result of herd immunity. Seroprevalence was 7.3% as of the end of April, if you assumed that the total number of infected is now double that (based on the death toll), then you arrive at about ~15% seroprevalence. Which is not likely to be sufficient for herd immunity. Much more likely that a combination of voluntary measures such as distancing and mask-wearing have combined to result in R (the reproductive number) being held consistently below 1.
  10. If it was the one from quite some time ago, I thought maybe that it wasn't "confirmed" that the teachers had got it from the students rather than the other way around. But I'll be honest, I didn't check for the details. It was a little too hard for me to imagine that an epidemiologist would have been completely unaware of or completely misinterpreted those results given the prominence of the findings, so I presumed it was a just a hedge. Honestly though, either way he's pushing an idea that really isn't supported by the data and that's awful. I'm actually forgiving of the notion that on balance, schools being open with precautions would be of net benefit in most countries (that have controlled their outbreak). But pretending there's no risk of transmission from children is ridiculous and potentially dangerous.
  11. Oh, so even with the hedge, he's just wrong. (the most charitable interpretation)
  12. There's a hedge there, he said "confirmed". If you search the news, in countries with COVID outbreaks linked to schools, there are plenty of teachers who got COVID, it's just that tracing can't determine who it was acquired from (via other staff, students etc.) There just haven't been school outbreaks in the countries that have extremely thorough contact tracing. (Edit: see post below, Australia confirmed students as a source for an outbreak that infected teachers. Also, need to check Korea.) He missed his calling, he should have been a politician.
  13. The article doesn't directly explain why the smallpox vaccine (among others) maintains complete effectiveness for very long periods of time. (although one of the scientists quoted to alludes to it) One of the major reasons is that smallpox has a long incubation time. This means that even in the absence of circulating antibodies, memory B-cells have time to proliferate and produce new ones. (The other reason is that smallpox has a very low mutation rate.) COVID has a fairly short incubation time, so a fairly probable result is that an effective vaccine won't prevent illness completely for very long, but will still be able to lessen the severity/duration of illness. I expect the worst-case scenario is that to maintain a high degree of protection, the COVID vaccine will be something that needs to be re-administered frequently, perhaps even every year like the flu shot. Hopefully, we'll find that a sufficient degree of protection lasts for significantly longer than that. But that's not something we're going to know for sure for a while.
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