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COVID-19 Coronavirus: general discussion


The first article is speculation with no data, apparently based on nothing more than the universal fact that acquired immunity to viruses isn't permanent but fades over time (normally years in otherwise healthy individuals; it's also not all or nothing, your immune system remembers how to produce a specific antibody for considerably longer than it is circulating that antibody in numbers large enough to provide total immunity).

The second article "raised questions" of re-infection but is believed to be dormancy and relapse.

Neither article seems to contain any compelling information to suggest that COVID-19 has any special properties for evading the immune system response.
 
I said this before but I do believe you CAN get the same cold or flu twice anyway. Having the anti-bodies is not a 100 percent guarantee of not getting it again, but it will likely be more mild the second time. Its also not really clear if some people were not actually completely free of the virus but just seemed to have recovered but didn't really. I have certainly had that happen many times in my own experience....thought I was good to go, then found I wasn't in a like a day or two.
 
I really do not get all this concern over no one having or not enough people having anti-bodies to this corona virus. This is, and always has been a thing. Every time a sufficiently new strain of cold or flu virus comes out (which is very often) this process of people making new anti-bodies for it happens.
When a cold or flu mutates within humans, a portion of the population is always immune. Those mutations are generally small, and it will take multiple generations of the virus before its descendents reinfect the same people.

When a virus mutates in another animal before transferring to humans, it can be unique, or at least be a long enough time that our systems have 'forgotten' that variation of virus. It's part of why Bird Flu and Swine Flu were such problems, it's not unique to COVID-19 (= Bat Pneumonia?). We have a whole process and science for flu immunizations though, while for coronavirus all we have is what we learned from SARS but never put into full-scale production as a cure.
 
Forgive me if this has already been posted but the math is scary.



The difference between the common flu and Covid-19 is the difference between 1.3^10 and 3^10: 59,000.
 
The big news this evening (apart from Charlie testing positive if you're a Brit) is that Yuriko Koike has asked Tokyo residents to stay at home this weekend unless they have important business. A good start but I'd rather see a full lockdown for a couple of weeks.
 
Neither article seems to contain any compelling information to suggest that COVID-19 has any special properties for evading the immune system response.
And this won't happen until all doctor's findings are compiled and leading infectious disease specialists can write a peer-reviewed journal about it. However, the data is so skewed because it's being hidden or not released. We can only take his word on it for now because a peer-reviewed journal can take months to get approval to be the most factual to publish in medical journals.
 
The difference between the common flu and Covid-19 is the difference between 1.3^10 and 3^10: 59,000.

That is some important math. The infection rate is so high not only because COVID-19 is highly contagious, but also because there is apparently no pre-existing immunity.

However, it's a very simplified story.

Assuming those base numbers are correct, it's more accurate if less dramatic to say that it's 1.3^X vs. 3.0^X, where X is the number of times the disease has been spread by current carriers to new patients. That simplified model (accurate only for initial spread where the base infection rate stays the same) looks like:

Generations:123456789101112131415
1.3^X1.692.22.863.714.826.278.1610.613.7817.9223.330.2939.3751.1966.54
3.0^X927812437292,1876,56119,68359,049177,147531,4411,594,3234,782,96914,384,90743,046,721

That shows the idea of why it spreads so fast, but it's not a strictly accurate model.

'X' is approximately the same as incubation period+illness period, although in practice disease don't propagate in discrete generations like a simple computer simulation (epidemiologists do more complex math to account for that, of course). Also there is probably a couple days early on where you are incubating but not yet contagious.

Also, in real epidemics the base number shrinks as the epidemic grows. The real number of new cases is not (# of exposures * infection chance), it's (# of exposures * (infection rate - "already sick or immune" proportion). Once 57% of the population already is or has been sick, the remaining spread will look like the beginning of a seasonal flu epidemic. Once more than 67% of the population has already been sick the base new infections (# of exposures * (infection rate - "already sick or immune" proportion) will be less then 1, and the total number of cases will start to shrink.

Of course, governments are also trying to reduce the infection rate by reducing the number of exposures. Where they succeed the virus could be contained before it naturally fades out. At least it will slow the spread dramatically for relatively modest success in reducing the number of exposures (you could work out a similar table
for e.g. 2.5^X to approximate a modestly successful exposure reduction, or whatever base number you believed would be the result of a given policy.)
 
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So for those of you in the Tokyo area... will Tokyo shut down in the near future. Just saw on the news this morning after last nights press with the mayor of Tokyo, people went out and bought groceries. We any of you in that crowd? Funny thing is by watching some of the shelves, it told be what was good and what was not so good. For frozen food from what I saw, looks like the Japanese products were low, but other countries food was still a lot available. I still by them beans from Thailand though. But I think I bought my last package now though.
 
Last night at 8:00pm the governor of Tokyo urged citizens to stay at home starting this weekend, and to avoid any unnecessary trips outside, work from home when possible, etc... She had announced a day or two earlier that Tokyo might have to go into lockdown. The announcement last night was short of a lockdown. It is unclear (to me) if she has the authority to actually stop traffic and commerce in the city, particularly since its so interconnected with the surrounding prefectures. Anyway, a lot of people ran for the shops once she announced these new requests. Some people had already started to prepare earlier once she made her "lockdown" reference. I was out last night about one hour before the announcement, and it was business as usual, although my friends were already whispering about stocking up on food.

I'll go outside later to see what the situation is, but looking at Twitter it seems a lot of stores are stripped of certain items. Ramen and other long-shelf-life foods are probably going to be the first to go.
 
Last night at 8:00pm the governor of Tokyo urged citizens to stay at home starting this weekend, and to avoid any unnecessary trips outside, work from home when possible, etc... She had announced a day or two earlier that Tokyo might have to go into lockdown. The announcement last night was short of a lockdown. It is unclear (to me) if she has the authority to actually stop traffic and commerce in the city, particularly since its so interconnected with the surrounding prefectures. Anyway, a lot of people ran for the shops once she announced these new requests. Some people had already started to prepare earlier once she made her "lockdown" reference. I was out last night about one hour before the announcement, and it was business as usual, although my friends were already whispering about stocking up on food.

I'll go outside later to see what the situation is, but looking at Twitter it seems a lot of stores are stripped of certain items. Ramen and other long-shelf-life foods are probably going to be the first to go.
The local 7-11 near my workplace in Tokyo has more gaps than usual but less than the evening after the 2011 earthquake. I don't think there's been too much panic buying, but now you should be taking the opportunity to get stuff that you regularly use but is perhaps less accessible (British teabags!).
 
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updates from medical staff in New York:


Here in northern California it's pretty quiet outside, the restaurants that remain open are take-out or delivery only and running a skeleton crew. Panic buying seems to still be a thing as the paper products aisle was empty at the local grocery store again. People who venture out keep a respectable distance from each other, and folks seem to be taking this seriously. We're keeping the curve tamped down pretty well up here, but southern CA might be a different story.
 
updates from medical staff in New York:


Here in northern California it's pretty quiet outside, the restaurants that remain open are take-out or delivery only and running a skeleton crew. Panic buying seems to still be a thing as the paper products aisle was empty at the local grocery store again. People who venture out keep a respectable distance from each other, and folks seem to be taking this seriously. We're keeping the curve tamped down pretty well up here, but southern CA might be a different story.


I see that Army tanks are being shipped by rail to Calif. Do you know anything about that. It might just be for training though. But having lived in LA during the Rodney King riots (which wasn't pretty at all ), I could see the use for military action now if the shtf. What do you think?
 
I see that Army tanks are being shipped by rail to Calif. Do you know anything about that. It might just be for training though. But having lived in LA during the Rodney King riots (which wasn't pretty at all ), I could see the use for military action now if the shtf. What do you think?
Just routine. Or so they say.
 
The local 7-11 near my workplace in Tokyo has more gaps than usual but less than the evening after the 2011 earthquake. I don't think there's been too much panic buying, but now you should be taking the opportunity to get stuff that you regularly use but is perhaps less accessible (British teabags!).

The situation is quite similar in our area. Not as severe as in 2011, but some of our supermarket shelves have been plundered: no more meat, pasta, milk, butter, tissue paper, and, of course, toilet paper. We have been filling up our stocks over the past few weeks but I doubt there will be any long-term shortages. And we have finally resorted to baking our own rye bread.

rye-bread.jpg
 
We have been filling up our stocks over the past few weeks but I doubt there will be any long-term shortages. And we have finally resorted to baking our own rye bread.
That bread looks great. We have a fancy Japanese bread maker which makes great bread although unfortunately my wife only likes white shokupan-style bread.

I agree shortages are unlikely but I would try to plan ahead so that you have to go out and shop as little as possible. No more than once/week.
Found out that my cousin is literally in the ICU from this virus fighting for his life today. :(
 
That bread looks great. We have a fancy Japanese bread maker which makes great bread although unfortunately my wife only likes white shokupan-style bread.

I agree shortages are unlikely but I would try to plan ahead so that you have to go out and shop as little as possible. No more than once/week.
Found out that my cousin is literally in the ICU from this virus fighting for his life today. :(
Get some 5kg bags of Ebetsu wholewheat flour. Great for mixing 50-50 with white flour for making bread with a bit more body and fibre.
 
For those interested in the math behind epidemic numbers and the effects of various strategies and behaviors on those numbers, 3Blue1Brown spends some time time simulating various epidemic models, doing a great job of explaining and illustrating in detail some of the math we were discussing earlier as well as touching on some topics that we haven't discussed in relation to those numbers. He covers travel between communities, travel to a central location, quarantine, social distancing, and various rates of transmission.

Simulating an Epidemic:


Philip Defranco managed to get an interview with Dr. Fauci. The doctor is much more clear and informative in this relaxed setting than he is under the stress of facing the white house press corps. The entire interview is worth listening to, IMO, however in particular he addresses the question of re-infection.

Re-infection question timestamp:


Whole video:
 
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