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Jason

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About Jason

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  • Birthday November 22

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    Toronto, Canada

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  1. I can confirm I hear more of this kind of dumb shit happening in Toronto than I would like to. I've been told of a family whose cleaner got sick with influenza-like illness and they were like "well, rather take our chances with COVID than having a dirty house". Gets worse, someone actually got sick afterwards, and then passed it along to someone else in another family because social distancing is apparently beneath them. On top of that no one is getting tested because they don't want to have to quarantine. To be clear, these are second-hand stories and everyone I personally know is being very responsible, but....
  2. Probably not by a meaningful amount. The percentage with undetectable antibodies within a few (3) weeks after infection is ~10%, it takes two to three months for ~40% to have undetectable antibodies in the the study cited - which would be a non-factor for most of the serology studies, which were done well within 2 months of case counts exploding in their respective locations. While we're on the subject - it's worth noting that that a lack of detectable circulating antibodies is not the same as having no immunity, the studies cited above didn't look for the presence of memory cells, but studies that have find them near-universally present. Memory cells are actually able to provide lifelong immunity against diseases with long incubation times (~2 weeks or longer) because the infection isn't able to cause illness before the memory cells proliferate. For diseases like COVID with a shorter incubation time, re-infection is possible but the illness will be milder and shorter in duration. (This is what happens with the flu, for example.)
  3. The best explanation for the rising case count in the US has to do with re-opening, not the protests. While it's true some states with large protests now have rising case counts, those states also had re-opening in the absence of mandatory mask-wearing. Many states that had large protests but did not have early re-openings have not seen a rise in case counts. An extensive study that compared the size of protests across 315 different US cities and their COVID case counts 3 weeks following the protests (more than enough time to see a spike in cases) found no evidence of a relationship. (https://www.nber.org/papers/w27408.pdf) It's true that there are a few cases linked to protest attendance, but it's a drop in the bucket compared to the overall rise in cases, and also no superspreader events have been identified. On the other hand, superspreader events have occured as a result of re-opening, such as the bar in Florida where 16 people caught COVID. In countries that have been doing extensive contact-tracing, >99% of transmissions have occured in enclosed environments. This also suggests that it's much more probable that re-opening of businesses and other indoor gatherings is the cause of the rise in cases.
  4. It's actually really important to maintain the isolation period even with adequate testing, because the test doesn't reliably detect viral DNA in the early stages of infection. I think New Zealand is testing its arrivals on day 3 and day 12 of the mandatory 14-day isolation period, as well as anyone displaying COVID-19 symptoms.
  5. The isolation period is long enough to discover illness if it exists, but only if testing is being done (repeatedly), because some people either don't have symptoms, or more commonly have symptoms they don't recognize. If illness does exist and isn't detected, a 14 day period is not long enough to exclude the possibility of a person being contagious after leaving isolation. (Imagine someone developing illness on day 10 and remaining contagious for a week thereafter, for example).
  6. "Scared" is a very generous interpretation of why this is happening. The migrant workers were required to isolate for two weeks upon initial entry, along with everyone else being given work exemptions arriving in Canada. There's no indication that the workers in question violated the rules. The problem is that everyone should be tested during that two week period, not just people who show symptoms, and it seems that's how an initial case slipped through the cracks before it spread to other workers. Testing everyone (during their isolation period) works and there's nothing discriminatory about it. I suspect the reason why everyone wasn't tested has to do with incompetence in one form or another, not because of concerns regarding targeting migrant workers. Isolation is clearly a lot more onerous than testing.
  7. All these problems also existed, yes. However, the deep sequencing of Canadian samples suggsests the bulk of our cases are of proximal US origin. This isn't remotely surprising. We have far more travel with the US than any other country, and we know now that the US had an enormous and mostly undetected outbreak at the time. Without screening and restrictions at the US border, other restrictions are rendered nearly meaningless.
  8. I haven't forgotten anything. I clearly acknowledged the existence of such statements in my post. The statements were not entirely misplaced - the early calls to close the border focused on cutting off travel from China, rather than closing all borders or screening all travellers. We can see from the US example that focusing on China did nothing to help; the US ended up with the worst outbreak in the world because it completely ignored travellers coming from other countries, particularly Europe. It's worth noting that the countries that did best very quickly implemented screening/quarantine for all travellers, not just those coming from China. I thought it was clearly implied that I agree our borders were closed too late. I disagree that the late closure has anything to do with the claims of racism, it's clear from the actual sequence of events the the government feared economic impacts rather than appearances of xenophobia or racism. If the primary concern was really about xenophobia/racism they would have closed all the borders at the same time, which would have been both more fair and (much) more effective. Instead, they left open the border where it was already clear the vast majority of new introductions were coming from. Presumably, that's because the Canadian government feared the repercussions of unilaterally restricting travel from the US without the US government's agreement. It definitely doesn't have anything to do with claims of racism - no one ever tried to suggest there would by anything racist about closing the US border.
  9. The only border closure that would have made a meaningful difference (and admittedly a large one) is closing the US border. The reason why that particular closing was delayed has nothing to do with the criticisms of racism/xenophobia. I think it's notable that the US border was closed later than other borders, despite being the main source of new introductions to Canada in March by a very large margin. Our earliest cases were from China, yes, but it turns out the vast majority of our cases have proximal US origin. An earlier closure of the border with China would have made little to no difference unless it coincided with a closure of the US border.
  10. There's already a lot of evidence - some of it cited in the PNAS article - that respiratory transmission is by far the dominant route of transmission. Essentially in countries with extensive contact tracing there are no transmissions that can be conclusively identified as being through fomites (contaminated objects) rather respiratory droplets - doesn't mean it never happens, but it does mean it can be ruled out as a possiblity for it to be a dominant factor. Outdoor transmission is open spaces is quite rare as well so leaving masks off outside is reasonable, as long as the space isn't enclosed in any way and there isn't prolonged proximity (which there usually isn't, spacing outdoors is much easier).
  11. I haven't been keeping up with this thread very well recently, so I apologize if the following has already been discussed. (I did try to look, didn't see them linked but maybe discussed obliquely?) I think their results are really, really important though, so can't hurt to bring them up again anyway. Something that has now shown up in multiple studies in countries with detailed contact tracing is that unlike other similarly transmissible diseases, the majority of transmission occurs from a small minority of individuals via superspreading events. In Hong Kong, 80% of transmission occurred from just 20% of individuals, and that was with moderate physical distancing measures in place. Some other data sets have indicated as few as 10% of individuals are responsible for 80% of transmission (particuarly before measures are put in place that particularly decrease the risk of superspreading) That's a really important result because recall that R for this virus is natively around 3 - in theory, blocking just superspreader events for this disease would be enough to bring R below 1. This was discussed in an NYT article (about 2 weeks ago) written by two epidemiologists involved in the Hong Kong study: https://www.nytimes.com/2020/06/02/opinion/coronavirus-superspreaders.html The other finding that's come out a bit more recently is that in Wuhan, Italy, and NYC, the mandating of face coverings was the strongest determinant of a reduction of transmission, even compared to measures such as physical distancing. Despite the numerous studies from East Asia showing the effectiveness of surgical masks at protecting the wearer, I don't think it was clear that masks would be so effective on a population-level in a place like NYC, where we know many people had to use homemade and otherwise untested cloth masks instead of surgical masks. https://www.pnas.org/content/early/2020/06/10/2009637117 Since pictures are worth a thousand words, their graph showing what happened to the trend of new cases after stay-at-home and face-covering was implemented in NYC, compared to elsewhere in the US where only stay-at-home was implemented. Further explanation if you're interested: If this trend only showed up in NYC I think we would have to strongly consider the possibility that an alternative explanation might be the cause. But with similar results also being observed in Italy and China, it's clear that even imperfect mask wearing can be very effective when adopted on a large scale, as a result of clear government directives. Taken together with the results regarding superspreading, it means that it's possible to safely resume most activities even without exhaustive testing and contact-tracing in place: mandatory mask wearing in public, and avoid conditions that lend to superspreading. (Crowds in enclosed spaces with socializing/talking etc.)
  12. Sorry for the late reply, I was completely overwhelmed that weekend and then forgot about it later. By now it may have already been discussed, but anyway - close, but there's a bit of nuance there. About a third of patients produce plasma doesn't neutralize at least half the virus at the lowest dilution tested (1:200). That's most likely to mean that levels of neutralizing antibodies were too low for detection, not that they hadn't been created at all. The means that when they exposed B-cells to SARS-CoV-2 antigens, some of them proliferated and at least some were found to produce antibodies specific to the receptor binding domain (RBD) of the virus, which is what's required for them to be "neutralizing".
  13. I'm very aware that RNA vaccines haven't been administed on a wide scale in humans before. But the post I replied to made a blanket statement about the risks of a vaccine being greater than COVID-19. And even if it was specifically referring to the Moderna vaccine - anyone suggesting the Moderna vaccine will be riskier than getting COVID-19 is, to be frank, talking out of their ass. There isn't any meaningful data from the Moderna vaccine to make that assessment. A severe reaction to a high dose in a phase 1 trial simply doesn't mean anything, the final version of the vaccine will not use the high dose, and if it turns out even low doses have a high rate of severe adverse reactions in phase 2/3, it won't be approved. Also, I think it's worth pointing out that RNA vaccines have been tested in animals before and in phase 1 human trials, and thus far the safety profile of RNA vaccines appears to be comparable (especially at the lower doses, which have been shown to be effective). The data doesn't exist to assert that they are as safe as traditional vaccines, but I think there's enough safety data to render any suggestion that they could be as risky as COVID-19 as completely absurd.
  14. The rate of severe reactions for viral vaccines that have actually gone through the full approval process is generally about 1 in 1 million. The chances of getting COVID-19 are going to remain way, way above 1 in 1 million in the vast majority of countries, including Canada. Mild reactions are such as soreness at the injection site are obviously more common than 1 in 1 million but are simply not comparable to getting COVID-19. To put it mildly, it doesn't make any sense at all to suggest that there's a greater risk from a vaccination than from COVID-19. (An exception would be someone with a known allergy to ingredients used in the vaccine. But such allergies are quite rare, and in any case that conclusion can't be drawn until an approved vaccine actually exists.)
  15. No, not really. All of the people in the trial with severe reactions had received the highest dose of the vaccine. A really important detail that makes the overall results of the Moderna trial good news is that the participates who had received low and moderate doses produced neutralizing antibodies at a level comparable to that resulting from natural infection and therefore probably sufficient for immunity. In fact, the phase 2/3 trials will not proceed with the high dose of the vaccine not just because of the adverse reactions but also because the low and medium doses produced a sufficient antibody response. Overall, the phase 1 trial results are (cautiously) good news, with the usual caveat that as a phase 1 trial, the sample was quite small. https://www.nytimes.com/2020/05/18/health/coronavirus-vaccine-moderna.html
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