5 ms·

NYC had only 20% prevalence in mid-June[1], after they had contained the initial outbreak[2]. Therefore, the drop in new cases is very unlikely to be from herd

by tghw 6y ago

NYC had only 20% prevalence in mid-June[1], after they had contained the initial outbreak[2]. Therefore, the drop in new cases is very unlikely to be from herd immunity, which would need prevalence to be in the 80% range. The author seems to ignore that most people are interacting with far fewer people because they are working from home, kids mostly aren't in school, and our other interactions with people outside our household have been limited and altered to decrease the chances of transmission. It's nice to think that some people had memory T-cells that could deal with the virus, and it seems some people do, but based on the original R0 numbers, it would be foolish to think that is the case for enough of the population to conclude that we've reached herd immunity. [1] https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/commercial-lab-surveys.html https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/comm... [2] https://coronavirus.jhu.edu/data/new-cases-50-states/new-york https://coronavirus.jhu.edu/data/new-cases-50-states/new-yor...

tghw 6y ago
Also, the JHU map is a poor indicator, as they are clearly basing the colors on suspect data, as in this case in Nebraska, which apparently had negative new cases yesterday. [1] https://www.dropbox.com/s/uakm0cfgn2hv94r/Nebraska.png?dl=0 https://www.dropbox.com/s/uakm0cfgn2hv94r/Nebraska.png?dl=0
- gloriosoc 6y ago
  Oh sometimes that happens because states make mistakes in reporting and want to correct them. I would guess that's the case here. It also happens in the other direction- big spikes are sometimes a backlog of cases all reported at once.
  - tghw 6y ago
    While true, that map and a photo of an outdoor space with people in it are poor pieces of data to hinge your entire argument on. You completely failed to take into account people working from home, schools delaying opening and not having been in session since March or April, and all of the other measures that have been put in place to decrease transmission (masks, barriers, decreased social interactions, restaurant closings, other indoor spaces being closed, etc, etc, etc). Your conclusion is flawed because you left all of these factors out of your analysis.
    - gloriosoc 6y ago
      I don't think this could explain the huge jump in cases and then decline post-reopening in Fl,Az, and LA. They aren't being more careful now than they were in early June. Disney world is open, people are outright refusing to distance or wear masks, the beaches are packed and yet we are seeing a drop in cases.
      - rallison 6y ago
        > They aren't being more careful now than they were in early June. Source? This is a significant claim. Early June was a low point in cases, hospitalizations and deaths. Lots of states were at peak reopening around then, as things seemed to be on the right track. For example, bars opened in early June in Florida. They closed on June 26th after cases started spiking. Louisiana was similar. The state started reopening May 15th. Later in June, bars were then closed back down again, and a mask mandate went into effect. In Arizona, the story is similar, with gyms, bars and movie theaters shutting back down in July after having opened in May. What sure seems to be the pattern is: things open up, cases rise, things close back down, cases drop. I'm not so sure that your "they aren't being more careful now than they were in early June" statement is accurate, and I think this is causing you to misattribute the cause of the drops in cases.
        gloriosoc 6y ago
        Mmmm You can see the timeline of orders that were put into place and the correlation. Here is Florida https://coronavirus.jhu.edu/data/state-timeline/new-confirmed-cases/florida/36 https://coronavirus.jhu.edu/data/state-timeline/new-confirme.... No mask mandate at all. Disney world is open. Beaches are open. The only order was bars are shut down. Without other distancing or masks, it's hard to believe that would stop spread.
        rallison 6y ago
        Florida as a whole enacted mask recommendations in late June. Miami Dade county enacted a mandatory mask mandate on July 2nd: https://www.miamidade.gov/global/initiatives/coronavirus/emergency-orders/emergency-order-20-20-amendment-1.page https://www.miamidade.gov/global/initiatives/coronavirus/eme... Palm Beach county enacted a mandatory mask mandate on June 25th: https://discover.pbcgov.org/PDF/COVID19/PBC-EO-12.pdf https://discover.pbcgov.org/PDF/COVID19/PBC-EO-12.pdf Hillsborough county enacted a mandatory mask mandate on June 22nd (if I'm reading it right): https://web.archive.org/web/20200706143937/https://www.hillsboroughcounty.org/library/hillsborough/media-center/documents/covid-19/epg-order-for-face-coverings.pdf https://web.archive.org/web/20200706143937/https://www.hills... Broward county enacted a mandatory mask mandate on July 8th: https://www.broward.org/CoronaVirus/Documents/EmergencyOrder20-21.pdf https://www.broward.org/CoronaVirus/Documents/EmergencyOrder... Orange county enacted a mandatory mask mandate on June 20th: https://www.orangecountyfl.net/portals/0/library/Emergency-Safety/docs/coronavirus/2020-23%20EEO.pdf https://www.orangecountyfl.net/portals/0/library/Emergency-S... Pinellas county enacted a mandatory mask mandate on June 24th: https://covid19.pinellascounty.org/wp-content/uploads/2020/06/Adopted-ORD-20-14.pdf https://covid19.pinellascounty.org/wp-content/uploads/2020/0... In just this list, we're up to mask mandates that cover counties that account for 10 million people, 47% of Florida's population, and accounting for the densest population centers. A number of additional counties also enacted mask mandates, but it got a bit tedious listing them all out. In other words, in the June-July period, mask mandates were enacted for a majority of the population of Florida. In another comment, I critiqued this piece as being a shallow analysis. Your comment here is an example of that.
- gloriosoc 6y ago
  It's fixed now btw
deleted 6y ago
[deleted]
newen 6y ago
It's very hard to trust these low prevalance numbers when, for example, I know a few people who are close friends with people in medical fields who tested positive but they themselves didn't get tested but had mild symptoms. I myself had mild symptoms that I'm 99% sure is covid and didn't get tested.
- tghw 6y ago
  Just because you and your friends weren't tested, doesn't mean the statistics are invalid. The link above was from random antibody testing and has a high confidence interval. I've been sick twice during this time. Thought it had to be COVID, but two PCR tests and an antibody test all came back negative. Maybe the tests are flawed, sure, but it's far more likely I just had something else.
avremel 6y ago
This article in the Atlantic mentions possible herd immunity at < 40%. https://www.theatlantic.com/health/archive/2020/07/herd-immunity-coronavirus/614035/ https://www.theatlantic.com/health/archive/2020/07/herd-immu...
- tghw 6y ago
  > Back in February, Lipsitch gave a very rough estimate that, absent intervention, herd immunity might happen after 40 to 70 percent of the population had been infected. Which is actually a mischaracterization of what the previous article[1] said: > Lipsitch predicts that within the coming year, some 40 to 70 percent of people around the world will be infected with the virus that causes COVID-19. At no point does he mention herd immunity. So, no, he's not saying herd immunity at 40%. [1] https://www.theatlantic.com/health/archive/2020/02/covid-vaccine/607000/ https://www.theatlantic.com/health/archive/2020/02/covid-vac...
rdtwo 6y ago
The theory was that some large percentage of population is either immune or at least significantly more resistant to covid. Do once the initial 20% get it the other 50-% are resistant so you get your 70% number that way
- tghw 6y ago
  Barring concrete evidence that is the case, it's a very dangerous assertion to make. It would also mean that the transmissibility of SARS-CoV-2 is much higher than we originally thought, amongst those without "natural immunity". Even if it were the case that half the population was naturally immune, we would want to understand why. The leading explanation at the moment is T-cells and previous exposure to other coronaviruses. Problem is, there's a good chance that previous exposures would be less likely in certain populations, like children, which could be especially problematic as we're debating sending kids back to school. At the very least, we need more data on T-cell prevalence/reactance to SARS-CoV-2 before we can jump to the conclusion that people are already immune. But right now, it's far more likely that we've seen drops because of the drastic measures that have been taken and the changes in daily behavior across the population.
  - anoncake 6y ago
    We already know that the virus is harmless to children. No need to grasp at straws to pretend that our collective hysteria was necessary.
    - Tainnor 6y ago
      While kids are less likely to get sick from it (less likely doesn't mean zero cases or even deaths btw), they can sure as hell spread it. There was some research suggesting that they're spreading the virus as much as (or not detectably less than) adults [1]. Yet at the same time, there are also some indications that kids might be less likely to become infected [2]. How that will affect school reopenings is anyone's guess. [1]: https://zoonosen.charite.de/fileadmin/user_upload/microsites/m_cc05/virologie-ccm/dateien_upload/Weitere_Dateien/analysis-of-SARS-CoV-2-viral-load-by-patient-age.pdf https://zoonosen.charite.de/fileadmin/user_upload/microsites... [2]: https://www.nature.com/articles/s41591-020-0962-9 https://www.nature.com/articles/s41591-020-0962-9

by tghw 6y ago

tghw 6y ago

Also, the JHU map is a poor indicator, as they are clearly basing the colors on suspect data, as in this case in Nebraska, which apparently had negative new cases yesterday. [1] https://www.dropbox.com/s/uakm0cfgn2hv94r/Nebraska.png?dl=0 https://www.dropbox.com/s/uakm0cfgn2hv94r/Nebraska.png?dl=0

gloriosoc 6y ago
Oh sometimes that happens because states make mistakes in reporting and want to correct them. I would guess that's the case here. It also happens in the other direction- big spikes are sometimes a backlog of cases all reported at once.
- tghw 6y ago
  While true, that map and a photo of an outdoor space with people in it are poor pieces of data to hinge your entire argument on. You completely failed to take into account people working from home, schools delaying opening and not having been in session since March or April, and all of the other measures that have been put in place to decrease transmission (masks, barriers, decreased social interactions, restaurant closings, other indoor spaces being closed, etc, etc, etc). Your conclusion is flawed because you left all of these factors out of your analysis.
  - gloriosoc 6y ago
    I don't think this could explain the huge jump in cases and then decline post-reopening in Fl,Az, and LA. They aren't being more careful now than they were in early June. Disney world is open, people are outright refusing to distance or wear masks, the beaches are packed and yet we are seeing a drop in cases.
    - rallison 6y ago
      > They aren't being more careful now than they were in early June. Source? This is a significant claim. Early June was a low point in cases, hospitalizations and deaths. Lots of states were at peak reopening around then, as things seemed to be on the right track. For example, bars opened in early June in Florida. They closed on June 26th after cases started spiking. Louisiana was similar. The state started reopening May 15th. Later in June, bars were then closed back down again, and a mask mandate went into effect. In Arizona, the story is similar, with gyms, bars and movie theaters shutting back down in July after having opened in May. What sure seems to be the pattern is: things open up, cases rise, things close back down, cases drop. I'm not so sure that your "they aren't being more careful now than they were in early June" statement is accurate, and I think this is causing you to misattribute the cause of the drops in cases.
      - gloriosoc 6y ago
        Mmmm You can see the timeline of orders that were put into place and the correlation. Here is Florida https://coronavirus.jhu.edu/data/state-timeline/new-confirmed-cases/florida/36 https://coronavirus.jhu.edu/data/state-timeline/new-confirme.... No mask mandate at all. Disney world is open. Beaches are open. The only order was bars are shut down. Without other distancing or masks, it's hard to believe that would stop spread.
        rallison 6y ago
        Florida as a whole enacted mask recommendations in late June. Miami Dade county enacted a mandatory mask mandate on July 2nd: https://www.miamidade.gov/global/initiatives/coronavirus/emergency-orders/emergency-order-20-20-amendment-1.page https://www.miamidade.gov/global/initiatives/coronavirus/eme... Palm Beach county enacted a mandatory mask mandate on June 25th: https://discover.pbcgov.org/PDF/COVID19/PBC-EO-12.pdf https://discover.pbcgov.org/PDF/COVID19/PBC-EO-12.pdf Hillsborough county enacted a mandatory mask mandate on June 22nd (if I'm reading it right): https://web.archive.org/web/20200706143937/https://www.hillsboroughcounty.org/library/hillsborough/media-center/documents/covid-19/epg-order-for-face-coverings.pdf https://web.archive.org/web/20200706143937/https://www.hills... Broward county enacted a mandatory mask mandate on July 8th: https://www.broward.org/CoronaVirus/Documents/EmergencyOrder20-21.pdf https://www.broward.org/CoronaVirus/Documents/EmergencyOrder... Orange county enacted a mandatory mask mandate on June 20th: https://www.orangecountyfl.net/portals/0/library/Emergency-Safety/docs/coronavirus/2020-23%20EEO.pdf https://www.orangecountyfl.net/portals/0/library/Emergency-S... Pinellas county enacted a mandatory mask mandate on June 24th: https://covid19.pinellascounty.org/wp-content/uploads/2020/06/Adopted-ORD-20-14.pdf https://covid19.pinellascounty.org/wp-content/uploads/2020/0... In just this list, we're up to mask mandates that cover counties that account for 10 million people, 47% of Florida's population, and accounting for the densest population centers. A number of additional counties also enacted mask mandates, but it got a bit tedious listing them all out. In other words, in the June-July period, mask mandates were enacted for a majority of the population of Florida. In another comment, I critiqued this piece as being a shallow analysis. Your comment here is an example of that.
gloriosoc 6y ago
It's fixed now btw

deleted 6y ago

[deleted]

newen 6y ago

It's very hard to trust these low prevalance numbers when, for example, I know a few people who are close friends with people in medical fields who tested positive but they themselves didn't get tested but had mild symptoms. I myself had mild symptoms that I'm 99% sure is covid and didn't get tested.

tghw 6y ago
Just because you and your friends weren't tested, doesn't mean the statistics are invalid. The link above was from random antibody testing and has a high confidence interval. I've been sick twice during this time. Thought it had to be COVID, but two PCR tests and an antibody test all came back negative. Maybe the tests are flawed, sure, but it's far more likely I just had something else.

avremel 6y ago

This article in the Atlantic mentions possible herd immunity at < 40%. https://www.theatlantic.com/health/archive/2020/07/herd-immunity-coronavirus/614035/ https://www.theatlantic.com/health/archive/2020/07/herd-immu...

tghw 6y ago
> Back in February, Lipsitch gave a very rough estimate that, absent intervention, herd immunity might happen after 40 to 70 percent of the population had been infected. Which is actually a mischaracterization of what the previous article[1] said: > Lipsitch predicts that within the coming year, some 40 to 70 percent of people around the world will be infected with the virus that causes COVID-19. At no point does he mention herd immunity. So, no, he's not saying herd immunity at 40%. [1] https://www.theatlantic.com/health/archive/2020/02/covid-vaccine/607000/ https://www.theatlantic.com/health/archive/2020/02/covid-vac...

rdtwo 6y ago

The theory was that some large percentage of population is either immune or at least significantly more resistant to covid. Do once the initial 20% get it the other 50-% are resistant so you get your 70% number that way

tghw 6y ago
Barring concrete evidence that is the case, it's a very dangerous assertion to make. It would also mean that the transmissibility of SARS-CoV-2 is much higher than we originally thought, amongst those without "natural immunity". Even if it were the case that half the population was naturally immune, we would want to understand why. The leading explanation at the moment is T-cells and previous exposure to other coronaviruses. Problem is, there's a good chance that previous exposures would be less likely in certain populations, like children, which could be especially problematic as we're debating sending kids back to school. At the very least, we need more data on T-cell prevalence/reactance to SARS-CoV-2 before we can jump to the conclusion that people are already immune. But right now, it's far more likely that we've seen drops because of the drastic measures that have been taken and the changes in daily behavior across the population.
- anoncake 6y ago
  We already know that the virus is harmless to children. No need to grasp at straws to pretend that our collective hysteria was necessary.
  - Tainnor 6y ago
    While kids are less likely to get sick from it (less likely doesn't mean zero cases or even deaths btw), they can sure as hell spread it. There was some research suggesting that they're spreading the virus as much as (or not detectably less than) adults [1]. Yet at the same time, there are also some indications that kids might be less likely to become infected [2]. How that will affect school reopenings is anyone's guess. [1]: https://zoonosen.charite.de/fileadmin/user_upload/microsites/m_cc05/virologie-ccm/dateien_upload/Weitere_Dateien/analysis-of-SARS-CoV-2-viral-load-by-patient-age.pdf https://zoonosen.charite.de/fileadmin/user_upload/microsites... [2]: https://www.nature.com/articles/s41591-020-0962-9 https://www.nature.com/articles/s41591-020-0962-9