3 ms·

The way that the areas that are now most resilient are the same areas with high population density which were hit very hard early on (NY, NJ, for example) tells

The way that the areas that are now most resilient are the same areas with high population density which were hit very hard early on (NY, NJ, for example) tells me that we have somehow hit herd immunity. There is some evidence coming out that other coronaviruses (which cause the common cold) could have causes immunity in some unknown percentage of the population, meaning the percentage of SARS-CoV-2 infection required to reach herd immunity is much lower than thought.

robbintt 6y ago
Share the evidence or delete the comment as misinformation.
- ohmaigad 6y ago
  https://www.nih.gov/news-events/nih-research-matters/immune-cells-common-cold-may-recognize-sars-cov-2 https://www.nih.gov/news-events/nih-research-matters/immune-... Can't comment on the other stuff.
- hodgesrm 6y ago
  The evidence is not hard to find. [1] Took me about 60 seconds. I would suggest in future supplying this to the conversation yourself as it makes for a more productive discussion. [1] https://www.nih.gov/news-events/nih-research-matters/immune-cells-common-cold-may-recognize-sars-cov-2 https://www.nih.gov/news-events/nih-research-matters/immune-...
- tripletao 6y ago
  Multiple papers (including one in Nature[1]) have reported T-cell immunity to SARS-CoV-2 in something between a third and half the samples collected before the pandemic. That doesn't mean the virus won't replicate in people with that pre-existing immunity, and there's evidence from homeless shelters and such of almost everyone testing positive (both by PCR and later for IgG in their blood); but people with that T cell immunity very likely get less sick, and might be less infectious (though near-certainly still infectious, and that's more speculative). And it seems from the hostility of your response ("delete the comment as misinformation") that you find it incredible that herd immunity could exist with less than 1 - 1/R0 of the population infected? But even ignoring any pre-existing immunity, that calculation assumes a homogeneous and well-mixed population. That's clearly not the case, since some people (a nurse in a crowded ER, a police officer, a store clerk, a nightlife enthusiast, etc.) have far more contacts than others (a remote worker who gets stuff delivered). People with more contacts will get infected first, with disproportionate harm, and then become immune first, with disproportionate benefit. Many papers have modeled[2] this; though no one's found a great way to measure that heterogeneity yet, so for now, it's hard to say much beyond that the effect exists, and is potentially big. And finally, herd immunity isn't a binary threshold, especially in a heterogeneous population. As others have noted, even places without enough immunity for R < 1 will still have slower spread than in a naive population, or may get to R < 1 from the immunity plus slightly more cautious behavior. Conversely, places that do have R < 1 overall may still have pockets of spread in sub-populations with unusually high R0. In any case, it's no conspiracy theory to believe that NYC developed significant amounts of immunity along the way to its ~24k (about 0.3% of the population!) deaths. 1. https://www.nature.com/articles/s41586-020-2550-z https://www.nature.com/articles/s41586-020-2550-z 2. https://www.medrxiv.org/content/10.1101/2020.02.10.20021725v2.full.pdf https://www.medrxiv.org/content/10.1101/2020.02.10.20021725v...
sacred_numbers 6y ago
The herd immunity threshold depends on behavior. It may be at 30% infected when the population is wearing masks and social distancing, but could be 70% if restrictions are removed. I agree that parts of New York City have probably reached herd immunity for current behavior patterns, so restrictions can probably be slightly relaxed, but 70% of the population is still vulnerable to infection, so you can't throw caution to the wind.
- jkinudsjknds 6y ago
  It also depends on interconnectedness of social networks. If the 30% that had it is highly concentrated in one sub group, then you might see low rates now, but high rates when groups start intermingling. Herd immunity at a national level won't save nursing homes, because almost by definition, there won't be herd immunity in that local community.
  - tripletao 6y ago
    Herd immunity at a national level while protecting the vulnerable will protect nursing homes to the extent it makes introduction of the virus into nursing homes less likely. You're correct that it does nothing to help the nursing homes once the virus gets introduced there, though.
  - dehrmann 6y ago
    This also means large, economy-driving cities, that thrive because of interconnected social networks will be slower to reopen, while rural communities might have never effectively shut down. NYC will be interesting to watch in this regard. If interconnectedness is the economic driver we think it is, we'll see slower growth until people return to cities. In the US, there's been some push for more national action around preventing/managing the spread of covid. While I agree that more national leadership is needed, and standard guidelines around reporting and degrees of "open" would be helpful, the US is so diverse a nation-wide lockdown never made sense, and there are enough complicated factors that the decision really has to be made at local levels.

robbintt 6y ago

Share the evidence or delete the comment as misinformation.

ohmaigad 6y ago
https://www.nih.gov/news-events/nih-research-matters/immune-cells-common-cold-may-recognize-sars-cov-2 https://www.nih.gov/news-events/nih-research-matters/immune-... Can't comment on the other stuff.
hodgesrm 6y ago
The evidence is not hard to find. [1] Took me about 60 seconds. I would suggest in future supplying this to the conversation yourself as it makes for a more productive discussion. [1] https://www.nih.gov/news-events/nih-research-matters/immune-cells-common-cold-may-recognize-sars-cov-2 https://www.nih.gov/news-events/nih-research-matters/immune-...
tripletao 6y ago
Multiple papers (including one in Nature[1]) have reported T-cell immunity to SARS-CoV-2 in something between a third and half the samples collected before the pandemic. That doesn't mean the virus won't replicate in people with that pre-existing immunity, and there's evidence from homeless shelters and such of almost everyone testing positive (both by PCR and later for IgG in their blood); but people with that T cell immunity very likely get less sick, and might be less infectious (though near-certainly still infectious, and that's more speculative). And it seems from the hostility of your response ("delete the comment as misinformation") that you find it incredible that herd immunity could exist with less than 1 - 1/R0 of the population infected? But even ignoring any pre-existing immunity, that calculation assumes a homogeneous and well-mixed population. That's clearly not the case, since some people (a nurse in a crowded ER, a police officer, a store clerk, a nightlife enthusiast, etc.) have far more contacts than others (a remote worker who gets stuff delivered). People with more contacts will get infected first, with disproportionate harm, and then become immune first, with disproportionate benefit. Many papers have modeled[2] this; though no one's found a great way to measure that heterogeneity yet, so for now, it's hard to say much beyond that the effect exists, and is potentially big. And finally, herd immunity isn't a binary threshold, especially in a heterogeneous population. As others have noted, even places without enough immunity for R < 1 will still have slower spread than in a naive population, or may get to R < 1 from the immunity plus slightly more cautious behavior. Conversely, places that do have R < 1 overall may still have pockets of spread in sub-populations with unusually high R0. In any case, it's no conspiracy theory to believe that NYC developed significant amounts of immunity along the way to its ~24k (about 0.3% of the population!) deaths. 1. https://www.nature.com/articles/s41586-020-2550-z https://www.nature.com/articles/s41586-020-2550-z 2. https://www.medrxiv.org/content/10.1101/2020.02.10.20021725v2.full.pdf https://www.medrxiv.org/content/10.1101/2020.02.10.20021725v...

sacred_numbers 6y ago

The herd immunity threshold depends on behavior. It may be at 30% infected when the population is wearing masks and social distancing, but could be 70% if restrictions are removed. I agree that parts of New York City have probably reached herd immunity for current behavior patterns, so restrictions can probably be slightly relaxed, but 70% of the population is still vulnerable to infection, so you can't throw caution to the wind.

jkinudsjknds 6y ago
It also depends on interconnectedness of social networks. If the 30% that had it is highly concentrated in one sub group, then you might see low rates now, but high rates when groups start intermingling. Herd immunity at a national level won't save nursing homes, because almost by definition, there won't be herd immunity in that local community.
- tripletao 6y ago
  Herd immunity at a national level while protecting the vulnerable will protect nursing homes to the extent it makes introduction of the virus into nursing homes less likely. You're correct that it does nothing to help the nursing homes once the virus gets introduced there, though.
- dehrmann 6y ago
  This also means large, economy-driving cities, that thrive because of interconnected social networks will be slower to reopen, while rural communities might have never effectively shut down. NYC will be interesting to watch in this regard. If interconnectedness is the economic driver we think it is, we'll see slower growth until people return to cities. In the US, there's been some push for more national action around preventing/managing the spread of covid. While I agree that more national leadership is needed, and standard guidelines around reporting and degrees of "open" would be helpful, the US is so diverse a nation-wide lockdown never made sense, and there are enough complicated factors that the decision really has to be made at local levels.