7 ms·

California shut down very hard and fast. When they reopened, nearly 100% of the population was still susceptible to the virus, so it spread like wildfire. Espec

California shut down very hard and fast. When they reopened, nearly 100% of the population was still susceptible to the virus, so it spread like wildfire. Especially since the reopening was not exactly slow. Compare this to the Northeast and much of Western Europe where the virus spread too quickly until lockdowns reduced the spread. Now, keeping the transmission rate low in those areas has become comparatively easy, even with wide-scale reopening. Perhaps California could have attempted a middle ground strategy. Let the virus spread just a slight amount more than occurred during the initial lockdown in order to gradually spread immunity. The level of immunity may be nowhere near "herd immunity", but any amount of immunity in a population makes transmission of the virus more difficult. EDIT: Part of why I make this strange argument is because CA seems to have endured a lockdown for virtually no gains. Now, the lockdowns will begin again. Perhaps allowing the virus to spread at a low and manageable rate would have conferred some benefits in terms of increased immunity in the population, thus making it easier to suppress the transmission rate moving forward.

wtvanhest 6y ago
I think we should wait to make determinations on cause until we see if that changes once the weather turns in the north and Europe and people return to heated spaces. If this was really a matter of herd immunity, Florida wouldn’t be getting hammered right now.
- standardUser 6y ago
  Why would Florida have high levels of immunity? It was never hit hard until recently. And I don't think this is about herd immunity, but simply about reducing the percent of the population that can infect and become infected, thus driving down the transmission rate.
- phonebanshee 6y ago
  Don't forget that idea is inverted for lots of the US (like Florida and Arizona). You gather indoors during the summer, in air conditioned spaces. Winter is when you're outside more often.
  - wtvanhest 6y ago
    That is what underlies my point. Basically, I don’t think we can say that Europe or the northern US has this beat yet. It doesn’t. Once winter comes again, we get the real numbers.
freeqaz 6y ago
What is the current sentiment on the pandemic like in California, given that they've been on lockdown for the longest? Are people getting antsy? Is there an "index" that measures sentiment across different states?
- SpicyLemonZest 6y ago
  "Lockdown" is perhaps a misleading description. The restrictions on private gatherings are entirely unenforced, and everyone I know has long since started having whatever gatherings they personally feel they need.
  - phonebanshee 6y ago
    Thinks are very different here in Seattle. No one I know is gathering with anyone indoors. You might have a couple friends over and stay outside, but indoor gatherings with multiple people are shocking insanity and just wouldn't happen.
  - ryandrake 6y ago
    Exactly. I wish people would stop referring to the feeble efforts the states implemented as "lockdowns". It's an absurd word to use. There were no lockdowns in the USA. There were a bunch of half-assed "Stay At Home" orders, which may as well have been called Stay At Home Suggestions because they were largely ignored. Nothing was locked. Nobody was locked in their homes. Few people, if any, were even subject to enforcement actions. Everywhere you looked during the so-called "lockdown" people were out and about, horsing around, going to parties, trying desperately to maintain business as usual, flexing their freedom just because. Every single place that the government begged people to not go, people went, saying "Nyaa Nnyaa! You can't tell me what to do!" Total eight-year-old mentality. The whole thing was a complete farce. Please, people, stop calling it a lockdown.
- nickff 6y ago
  It might be helpful to look at Google mobility trends; I know that there was 'shutdown fatigue' almost everywhere (according to GMT).
pettazz 6y ago
The reason for case counts staying relatively low in those places has a lot less to do with "herd immunity" and a lot more to do with still being careful. Even though a huge number of people were infected, it was still a very small amount of the population overall, not anywhere near enough to affect the transmission rate with no restrictions. https://www.cnbc.com/2020/07/07/herd-immunity-questioned-after-spanish-coronavirus-antibody-study.html https://www.cnbc.com/2020/07/07/herd-immunity-questioned-aft... In MA we're not even close to entirely reopened yet, but as we continue step by step the transmission rate is ticking back up unfortunately: https://rt.live/us/MA https://rt.live/us/MA
- standardUser 6y ago
  If you look at the numbers throughout the Northeast, you see a remarkable consistency. New cases are at a trickle, despite lots of reopening (more in some places than others) and weeks of mass protests throughout the larger cities. I am in NYC and mask compliance here is... OK. But people are generally going out a lot, eating out a lot, shopping, etc, with very little concern. Weeks keep passing without even a tiny uptick in the rate of new cases. Clearly, there is something suppressing the transmission rate in this region. The exact same holds true for Europe.
  - mjmahone17 6y ago
    If you haven’t left NYC, it may also be true that our perception of “going out a lot” is about equivalent to much of the nation’s “lockdown” perception. In other parts of the country, like Florida and Arizona, it doesn’t seem like the transmission rate ever really went below 1: it just hovered around 1. So now NY, Boston, etc are “opening up” to a roughly equivalent position that those states were in when they were under “total lockdown”: in NYC, we still don’t have indoor dining, for example, whereas Arizona still allows 50% capacity indoor dining despite nearly running out of ICU beds in most hospitals. When you’re in the center of the epidemic, merely getting to an infection rate of 1 is not good enough. NYC got well below that. I don’t think everywhere else did, and even the places “shutting down again” may not be doing enough.
pmoriarty 6y ago
"Perhaps California could have attempted a middle ground strategy. Let the virus spread just a slight amount more than occurred during the initial lockdown in order to gradually spread immunity." It's not even clear yet whether exposure to this virus confers immunity, nor how long such immunity would last if it does exist. From the newest episode of This Week in Virology[1]: Daniel Griffin: The tough thing, right, is that if you look at the "common" coronaviruses, they don't give us long-lasting immunity. Traditionally you could be reinfected multiple times in the same year. ... We've known this for the other coronaviruses, that if you get OC43 or 229e or any of the other, you don't get lifelong immunity, you can get sick again, and it's not clear that that second infection is milder than the first. My word of caution is to be careful about, you know, when we hear that 5 or 10 percent of the population is seropositive, I don't know what that means yet. [1] - starting at about 14'34" in to episode 638: https://www.microbe.tv/twiv/twiv-638/ https://www.microbe.tv/twiv/twiv-638/
- standardUser 6y ago
  Though it has not been conclusively proven, literally all signs point to meanginful immunity and virtually no signs point to the opposite. Dozens of vaccines are being developed on this assumption, and there have been zero confirmed instances of reinfection of a fully recovered individual.
  - jhowell 6y ago
    > all signs point to meanginful immunity and virtually no signs point to the opposite. Here is a story from CNN via the Mercury News about 3 teachers sharing a classroom. Anecdotal, but makes me think these are signs of a lack of immunity. A positive, negative, positive test. > A month after they caught the virus that killed their colleague, Martinez and Skillings are still struggling. > Martinez says fatigue is lingering, she still has a cough, and she continues to take breathing treatments to relieve tightness in her chest. She recently tested negative and retested. > Skillings says she thought she was getting better, but recently her cough returned full force. She tested a week ago and it came back positive again. https://www.mercurynews.com/2020/07/12/three-arizona-teachers-who-shared-a-classroom-got-coronavirus-one-of-them-died/ https://www.mercurynews.com/2020/07/12/three-arizona-teacher...
redis_mlc 6y ago
> California shut down very hard and fast. When they reopened, nearly 100% of the population was still susceptible to the virus LAX and SFO had daily flights from Wuhan and Shanghai, so it's likely that corona has been here since Dec. The test results say 3% positive, but it's likely much higher.
AlexandrB 6y ago
The effectiveness of a middle ground strategy is pure conjecture. Canada shut down fast and hard - like California - and is not seeing cases spike. Perhaps because we re-opened slowly and people are still generally cautious - wearing masks in public and maintaining social distance. Or perhaps because we have not been getting wildly mixed messages from local/provincial/national leaders about the severity of the situation or what to do about it.
- SpicyLemonZest 6y ago
  My understanding is that Canada is currently at the stage of reopening that California is rolling back to, where gyms, indoor restaurants, and movie theaters are closed.
  - AlexandrB 6y ago
    Yup, that's the case in Ontario. Mask wearing is also now mandatory indoors. I guess the question is why did California rush to re-open fully?
    - SpicyLemonZest 6y ago
      The governor's been clear that's part of the intended strategy; counties will be allowed to rush forwards as long as infection rates remain low, and then pull back if infections rise. He's consistently warned that some rollbacks should be expected.
      - QuercusMax 6y ago
        The problem with this strategy is that it's been incredibly confusing; I'm getting whiplash from all the back-and-forth. The news reporting has been bad, as well, not clearly distinguishing between statewide and per-county (or for counties on the "watch list", which changes daily). My friends who are in the service industry have to figure out from day-to-day what they're going to be doing. This is just a giant mess.
TomVDB 6y ago
> ... but any amount of immunity in a population makes transmission of the virus more difficult. That may be true from a pure logical/mathematical point of view, but that doesn't mean it makes a practical difference. Herd immunity is something that happens when a very large percentage of the population is immune. For mumps (which has a very high R0), you need about 92% immunity level for it to be effective. For COVID-19, it is currently estimated to be around 60+%. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7151357/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7151357/) We are nowhere near these kind of immunity levels right now, and it's impossible to get to that level without vaccine unless you're willing to accept that a huge amount of people will die or get seriously ill. Any suggestion that herd immunity is relevant in today's environment is plain wrong.
- novaRom 6y ago
  But we knew it since March. Any reason to not believe Angela Merkel who says continuously it's just beginning and will last years? Now we even know there's probably no long term immunity. Antibodies to other coronaviruses last around 12 months, so COVID-19 case might be similar.
- standardUser 6y ago
  I did not suggest herd immunity has occurred. You seem to be confusing the idea of herd immunity with the similar idea that any immunity in a population will reduce the transmission rate by some amount.
  - TomVDB 6y ago
    You’re saying that maybe CA should have done some middle ground closure since that might have help a little more with increasing immunity. My point is that the goal of increasing immunity is pointless unless it can be raised to a very high percentage and without taking massive casualties. Without a vaccine, that’s simply not possible for COVID-19. And thus that suggestion doesn’t make a lot of I sense. The benefit of a slight higher but still very low level of immunity is so small that there’s no point.
dominotw 6y ago
This is the same thing that happened in India. Precious lockdown token was used up too early, now they can't go back to lockdown again even thought its speading like wildfire.
yongjik 6y ago
I'm not a virologist, but it seems like even in NYC the antibody test was "only" ~20% positive. ~30% if you drill down to certain subgruops: https://www.6sqft.com/new-york-covid-antibody-test-preliminary-results/ https://www.6sqft.com/new-york-covid-antibody-test-prelimina... I think it would mean, even in NYC, its current "herd immunity" would reduce the so-called R value by only 20%. That doesn't sound enough to explain the difference between NY and CA.
- irq11 6y ago
  There have been multiple publications in the last month suggesting that a substantial fraction (i.e. 40% or more) of the population could have some level of cell-mediated immunity to the virus. https://www.sciencemag.org/news/2020/05/t-cells-found-covid-19-patients-bode-well-long-term-immunity https://www.sciencemag.org/news/2020/05/t-cells-found-covid-... https://www.biorxiv.org/content/10.1101/2020.06.29.174888v1 https://www.biorxiv.org/content/10.1101/2020.06.29.174888v1 On top of that, the threshold where growth slows is substantially lower than the “herd immunity threshold” that is naïvely calculated from R0. The flu almost never infects more than 10-15% of the population, despite an R0 of around 1.8, and a corresponding “herd immunity” threshold in the 50% range. A recent Science paper suggested a more reasonable herd immunity threshold of 43% for Sars-CoV2. https://science.sciencemag.org/content/early/2020/06/22/science.abc6810 https://science.sciencemag.org/content/early/2020/06/22/scie... Between the two, it’s not inconceivable that NYC has reached the point where virus transmission is substantially self-limited. It’s not even a remote possibility - it’s likely.
- cma 6y ago
  If you look at the subgroup of most socially connected people most likely to come into lots of contact with other people, they probably hit really high numbers. And then those "hub" people being immune could have an outsized effect on reducing further spread. I have no idea of he numbers though and if it is playing a large role.
ScottBurson 6y ago
It's easy to be misled by the nature of exponential growth. In most people's vocabularies these days, the term seems to mean just "very fast", but correctly understood, it's more specific and more complex than that. Exponential growth, in this context, means that the rate of new infections is proportional to the number of existing infections. This cuts both ways: when the number of existing infections is large, the rate of growth is also large -- which is why exponential growth is so dangerous -- but when the existing number is small, the growth rate is also small. If you look at a graph of an exponential curve, there's a long relatively flat region to the left, before the knee in the curve is hit and the thing takes off. The point is, even though we here in CA started the lockdown relatively early, we've never gotten the case numbers down to a manageable level. I'm not sure why not. Although a lot of us have taken the virus seriously from the beginning, maybe there are still too many who don't. The sad truth is that a lot of people won't believe it until it affects someone they know -- and while it's well under control, that tends not to happen. So it looks like a bad outbreak in a region creates "mental herd immunity", where almost everyone cooperates with the lockdown; places that haven't had such an outbreak don't take it as seriously.
- dragonwriter 6y ago
  > The point is, even though we here in CA started the lockdown relatively early, we've never gotten the case numbers down to a manageable level. I'm not sure why not. Because we started reopening just as the curve was flattening, without bending the numbers down much.
- trevyn 6y ago
  The visual “knee” is purely a result of your chosen scale; there is no scale-independent mathematical definition. Put it on a log/log chart, and it’s a straight line; no part of the growth is qualitatively different than any other.
  - ScottBurson 6y ago
    I'm well aware of that -- except that an exponential is a straight line on a semi-log chart. But to people hearing the numbers, who aren't familiar with the phenomenon of exponential growth, a linear scale, despite being somewhat arbitrary, better captures the psychological impact. Consider an idealized example: we start with one case, and a doubling time of three days. It takes the whole first month to get to about 1000 cases. Even though you and I know that that's an extremely aggressive growth rate, 1000 cases still doesn't sound like a lot to many people, when they compare it to the population of the US (or annual numbers of deaths from various other causes, like swimming pool accidents -- a comparison I've actually heard made). In the next month, though, it would get to 1M cases, which is a much larger fraction of the population and is correspondingly likelier to get people's attention.
EricE 6y ago
Sweeden didn't lock down at all: https://youtu.be/z34ILhFs-xs?t=182 https://youtu.be/z34ILhFs-xs?t=182 There is little evidence the lockdowns did a damn thing.
- mchusma 6y ago
  Resuming the lockdown, particularly in such a sudden fashion, is just blow after blow. Such small benefit for such enormous cost. I am not convinced this could get through the legislature. I'm also confused how "emergency powers" can last for Governor's to have almost unlimited power for 4 months now.
ryandrake 6y ago
As someone with weak lungs and a weak immune system, how about we not deliberately let the virus spread, mmmkay? That would be really super. How about, instead, we actually implement a Stay At Home order with teeth and enforcement, and actually try to wait this out until a vaccine becomes available. Unlike what we did which was an overtly unenforced Stay At Home Suggestion that people predictably ignored.. > Part of why I make this strange argument is because CA seems to have endured a lockdown for virtually no gains. California never implemented a lockdown. The people staying home did so voluntarily, but the rest were out horsing around as usual doing whatever non-essential tasks they could find among what businesses they could find that were also defying the "order". Putting everyone else at risk who had to step out to do actual essentials like limited grocery shopping.

wtvanhest 6y ago

I think we should wait to make determinations on cause until we see if that changes once the weather turns in the north and Europe and people return to heated spaces. If this was really a matter of herd immunity, Florida wouldn’t be getting hammered right now.

standardUser 6y ago
Why would Florida have high levels of immunity? It was never hit hard until recently. And I don't think this is about herd immunity, but simply about reducing the percent of the population that can infect and become infected, thus driving down the transmission rate.
phonebanshee 6y ago
Don't forget that idea is inverted for lots of the US (like Florida and Arizona). You gather indoors during the summer, in air conditioned spaces. Winter is when you're outside more often.
- wtvanhest 6y ago
  That is what underlies my point. Basically, I don’t think we can say that Europe or the northern US has this beat yet. It doesn’t. Once winter comes again, we get the real numbers.

freeqaz 6y ago

What is the current sentiment on the pandemic like in California, given that they've been on lockdown for the longest? Are people getting antsy? Is there an "index" that measures sentiment across different states?

SpicyLemonZest 6y ago
"Lockdown" is perhaps a misleading description. The restrictions on private gatherings are entirely unenforced, and everyone I know has long since started having whatever gatherings they personally feel they need.
- phonebanshee 6y ago
  Thinks are very different here in Seattle. No one I know is gathering with anyone indoors. You might have a couple friends over and stay outside, but indoor gatherings with multiple people are shocking insanity and just wouldn't happen.
- ryandrake 6y ago
  Exactly. I wish people would stop referring to the feeble efforts the states implemented as "lockdowns". It's an absurd word to use. There were no lockdowns in the USA. There were a bunch of half-assed "Stay At Home" orders, which may as well have been called Stay At Home Suggestions because they were largely ignored. Nothing was locked. Nobody was locked in their homes. Few people, if any, were even subject to enforcement actions. Everywhere you looked during the so-called "lockdown" people were out and about, horsing around, going to parties, trying desperately to maintain business as usual, flexing their freedom just because. Every single place that the government begged people to not go, people went, saying "Nyaa Nnyaa! You can't tell me what to do!" Total eight-year-old mentality. The whole thing was a complete farce. Please, people, stop calling it a lockdown.
nickff 6y ago
It might be helpful to look at Google mobility trends; I know that there was 'shutdown fatigue' almost everywhere (according to GMT).

pettazz 6y ago

The reason for case counts staying relatively low in those places has a lot less to do with "herd immunity" and a lot more to do with still being careful. Even though a huge number of people were infected, it was still a very small amount of the population overall, not anywhere near enough to affect the transmission rate with no restrictions. https://www.cnbc.com/2020/07/07/herd-immunity-questioned-after-spanish-coronavirus-antibody-study.html https://www.cnbc.com/2020/07/07/herd-immunity-questioned-aft... In MA we're not even close to entirely reopened yet, but as we continue step by step the transmission rate is ticking back up unfortunately: https://rt.live/us/MA https://rt.live/us/MA

standardUser 6y ago
If you look at the numbers throughout the Northeast, you see a remarkable consistency. New cases are at a trickle, despite lots of reopening (more in some places than others) and weeks of mass protests throughout the larger cities. I am in NYC and mask compliance here is... OK. But people are generally going out a lot, eating out a lot, shopping, etc, with very little concern. Weeks keep passing without even a tiny uptick in the rate of new cases. Clearly, there is something suppressing the transmission rate in this region. The exact same holds true for Europe.
- mjmahone17 6y ago
  If you haven’t left NYC, it may also be true that our perception of “going out a lot” is about equivalent to much of the nation’s “lockdown” perception. In other parts of the country, like Florida and Arizona, it doesn’t seem like the transmission rate ever really went below 1: it just hovered around 1. So now NY, Boston, etc are “opening up” to a roughly equivalent position that those states were in when they were under “total lockdown”: in NYC, we still don’t have indoor dining, for example, whereas Arizona still allows 50% capacity indoor dining despite nearly running out of ICU beds in most hospitals. When you’re in the center of the epidemic, merely getting to an infection rate of 1 is not good enough. NYC got well below that. I don’t think everywhere else did, and even the places “shutting down again” may not be doing enough.

pmoriarty 6y ago

"Perhaps California could have attempted a middle ground strategy. Let the virus spread just a slight amount more than occurred during the initial lockdown in order to gradually spread immunity." It's not even clear yet whether exposure to this virus confers immunity, nor how long such immunity would last if it does exist. From the newest episode of This Week in Virology[1]: Daniel Griffin: The tough thing, right, is that if you look at the "common" coronaviruses, they don't give us long-lasting immunity. Traditionally you could be reinfected multiple times in the same year. ... We've known this for the other coronaviruses, that if you get OC43 or 229e or any of the other, you don't get lifelong immunity, you can get sick again, and it's not clear that that second infection is milder than the first. My word of caution is to be careful about, you know, when we hear that 5 or 10 percent of the population is seropositive, I don't know what that means yet. [1] - starting at about 14'34" in to episode 638: https://www.microbe.tv/twiv/twiv-638/ https://www.microbe.tv/twiv/twiv-638/

standardUser 6y ago
Though it has not been conclusively proven, literally all signs point to meanginful immunity and virtually no signs point to the opposite. Dozens of vaccines are being developed on this assumption, and there have been zero confirmed instances of reinfection of a fully recovered individual.
- jhowell 6y ago
  > all signs point to meanginful immunity and virtually no signs point to the opposite. Here is a story from CNN via the Mercury News about 3 teachers sharing a classroom. Anecdotal, but makes me think these are signs of a lack of immunity. A positive, negative, positive test. > A month after they caught the virus that killed their colleague, Martinez and Skillings are still struggling. > Martinez says fatigue is lingering, she still has a cough, and she continues to take breathing treatments to relieve tightness in her chest. She recently tested negative and retested. > Skillings says she thought she was getting better, but recently her cough returned full force. She tested a week ago and it came back positive again. https://www.mercurynews.com/2020/07/12/three-arizona-teachers-who-shared-a-classroom-got-coronavirus-one-of-them-died/ https://www.mercurynews.com/2020/07/12/three-arizona-teacher...

redis_mlc 6y ago

> California shut down very hard and fast. When they reopened, nearly 100% of the population was still susceptible to the virus LAX and SFO had daily flights from Wuhan and Shanghai, so it's likely that corona has been here since Dec. The test results say 3% positive, but it's likely much higher.

AlexandrB 6y ago

The effectiveness of a middle ground strategy is pure conjecture. Canada shut down fast and hard - like California - and is not seeing cases spike. Perhaps because we re-opened slowly and people are still generally cautious - wearing masks in public and maintaining social distance. Or perhaps because we have not been getting wildly mixed messages from local/provincial/national leaders about the severity of the situation or what to do about it.

SpicyLemonZest 6y ago
My understanding is that Canada is currently at the stage of reopening that California is rolling back to, where gyms, indoor restaurants, and movie theaters are closed.
- AlexandrB 6y ago
  Yup, that's the case in Ontario. Mask wearing is also now mandatory indoors. I guess the question is why did California rush to re-open fully?
  - SpicyLemonZest 6y ago
    The governor's been clear that's part of the intended strategy; counties will be allowed to rush forwards as long as infection rates remain low, and then pull back if infections rise. He's consistently warned that some rollbacks should be expected.
    - QuercusMax 6y ago
      The problem with this strategy is that it's been incredibly confusing; I'm getting whiplash from all the back-and-forth. The news reporting has been bad, as well, not clearly distinguishing between statewide and per-county (or for counties on the "watch list", which changes daily). My friends who are in the service industry have to figure out from day-to-day what they're going to be doing. This is just a giant mess.

TomVDB 6y ago

> ... but any amount of immunity in a population makes transmission of the virus more difficult. That may be true from a pure logical/mathematical point of view, but that doesn't mean it makes a practical difference. Herd immunity is something that happens when a very large percentage of the population is immune. For mumps (which has a very high R0), you need about 92% immunity level for it to be effective. For COVID-19, it is currently estimated to be around 60+%. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7151357/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7151357/) We are nowhere near these kind of immunity levels right now, and it's impossible to get to that level without vaccine unless you're willing to accept that a huge amount of people will die or get seriously ill. Any suggestion that herd immunity is relevant in today's environment is plain wrong.

novaRom 6y ago
But we knew it since March. Any reason to not believe Angela Merkel who says continuously it's just beginning and will last years? Now we even know there's probably no long term immunity. Antibodies to other coronaviruses last around 12 months, so COVID-19 case might be similar.
standardUser 6y ago
I did not suggest herd immunity has occurred. You seem to be confusing the idea of herd immunity with the similar idea that any immunity in a population will reduce the transmission rate by some amount.
- TomVDB 6y ago
  You’re saying that maybe CA should have done some middle ground closure since that might have help a little more with increasing immunity. My point is that the goal of increasing immunity is pointless unless it can be raised to a very high percentage and without taking massive casualties. Without a vaccine, that’s simply not possible for COVID-19. And thus that suggestion doesn’t make a lot of I sense. The benefit of a slight higher but still very low level of immunity is so small that there’s no point.

dominotw 6y ago

This is the same thing that happened in India. Precious lockdown token was used up too early, now they can't go back to lockdown again even thought its speading like wildfire.

yongjik 6y ago

I'm not a virologist, but it seems like even in NYC the antibody test was "only" ~20% positive. ~30% if you drill down to certain subgruops: https://www.6sqft.com/new-york-covid-antibody-test-preliminary-results/ https://www.6sqft.com/new-york-covid-antibody-test-prelimina... I think it would mean, even in NYC, its current "herd immunity" would reduce the so-called R value by only 20%. That doesn't sound enough to explain the difference between NY and CA.

irq11 6y ago
There have been multiple publications in the last month suggesting that a substantial fraction (i.e. 40% or more) of the population could have some level of cell-mediated immunity to the virus. https://www.sciencemag.org/news/2020/05/t-cells-found-covid-19-patients-bode-well-long-term-immunity https://www.sciencemag.org/news/2020/05/t-cells-found-covid-... https://www.biorxiv.org/content/10.1101/2020.06.29.174888v1 https://www.biorxiv.org/content/10.1101/2020.06.29.174888v1 On top of that, the threshold where growth slows is substantially lower than the “herd immunity threshold” that is naïvely calculated from R0. The flu almost never infects more than 10-15% of the population, despite an R0 of around 1.8, and a corresponding “herd immunity” threshold in the 50% range. A recent Science paper suggested a more reasonable herd immunity threshold of 43% for Sars-CoV2. https://science.sciencemag.org/content/early/2020/06/22/science.abc6810 https://science.sciencemag.org/content/early/2020/06/22/scie... Between the two, it’s not inconceivable that NYC has reached the point where virus transmission is substantially self-limited. It’s not even a remote possibility - it’s likely.
cma 6y ago
If you look at the subgroup of most socially connected people most likely to come into lots of contact with other people, they probably hit really high numbers. And then those "hub" people being immune could have an outsized effect on reducing further spread. I have no idea of he numbers though and if it is playing a large role.

ScottBurson 6y ago

It's easy to be misled by the nature of exponential growth. In most people's vocabularies these days, the term seems to mean just "very fast", but correctly understood, it's more specific and more complex than that. Exponential growth, in this context, means that the rate of new infections is proportional to the number of existing infections. This cuts both ways: when the number of existing infections is large, the rate of growth is also large -- which is why exponential growth is so dangerous -- but when the existing number is small, the growth rate is also small. If you look at a graph of an exponential curve, there's a long relatively flat region to the left, before the knee in the curve is hit and the thing takes off. The point is, even though we here in CA started the lockdown relatively early, we've never gotten the case numbers down to a manageable level. I'm not sure why not. Although a lot of us have taken the virus seriously from the beginning, maybe there are still too many who don't. The sad truth is that a lot of people won't believe it until it affects someone they know -- and while it's well under control, that tends not to happen. So it looks like a bad outbreak in a region creates "mental herd immunity", where almost everyone cooperates with the lockdown; places that haven't had such an outbreak don't take it as seriously.

dragonwriter 6y ago
> The point is, even though we here in CA started the lockdown relatively early, we've never gotten the case numbers down to a manageable level. I'm not sure why not. Because we started reopening just as the curve was flattening, without bending the numbers down much.
trevyn 6y ago
The visual “knee” is purely a result of your chosen scale; there is no scale-independent mathematical definition. Put it on a log/log chart, and it’s a straight line; no part of the growth is qualitatively different than any other.
- ScottBurson 6y ago
  I'm well aware of that -- except that an exponential is a straight line on a semi-log chart. But to people hearing the numbers, who aren't familiar with the phenomenon of exponential growth, a linear scale, despite being somewhat arbitrary, better captures the psychological impact. Consider an idealized example: we start with one case, and a doubling time of three days. It takes the whole first month to get to about 1000 cases. Even though you and I know that that's an extremely aggressive growth rate, 1000 cases still doesn't sound like a lot to many people, when they compare it to the population of the US (or annual numbers of deaths from various other causes, like swimming pool accidents -- a comparison I've actually heard made). In the next month, though, it would get to 1M cases, which is a much larger fraction of the population and is correspondingly likelier to get people's attention.

EricE 6y ago

Sweeden didn't lock down at all: https://youtu.be/z34ILhFs-xs?t=182 https://youtu.be/z34ILhFs-xs?t=182 There is little evidence the lockdowns did a damn thing.

mchusma 6y ago
Resuming the lockdown, particularly in such a sudden fashion, is just blow after blow. Such small benefit for such enormous cost. I am not convinced this could get through the legislature. I'm also confused how "emergency powers" can last for Governor's to have almost unlimited power for 4 months now.

ryandrake 6y ago

As someone with weak lungs and a weak immune system, how about we not deliberately let the virus spread, mmmkay? That would be really super. How about, instead, we actually implement a Stay At Home order with teeth and enforcement, and actually try to wait this out until a vaccine becomes available. Unlike what we did which was an overtly unenforced Stay At Home Suggestion that people predictably ignored.. > Part of why I make this strange argument is because CA seems to have endured a lockdown for virtually no gains. California never implemented a lockdown. The people staying home did so voluntarily, but the rest were out horsing around as usual doing whatever non-essential tasks they could find among what businesses they could find that were also defying the "order". Putting everyone else at risk who had to step out to do actual essentials like limited grocery shopping.