9 ms·

Population-level herd immunity against Covid-19 will not be achieved in 2020

64 points by arunbahl 6y ago

josefresco 6y ago
I would liked to have read their opinions on Sweden.
- lucideer 6y ago
  Do you live in Sweden? A lot of people seem to be using it as some example of a country who haven't introduced lockdown measures, whereas in reality they are actually self-isolating and social distancing, just like everyone else. Worth noting also that Sweden has the 6th highest case fatality rate in Europe (other Nordic countries are near the bottom of that list).
  - josefresco 6y ago
    I don't, but I've read enough to be aware of their approach which is to socially distance, protect the vulnerable but other than that, operate on a semi-normal basis. Kids go to school, adults go to work. Just wondering if they project Sweden to have any sort of "herd immunity" in the short/medium/long term timeframe.
    - irchans 6y ago
      I imagine that a large percentage (maybe 10%, maybe more) of the children in Sweden have been infected because they have more daily contacts and they "work" in crowded rooms. I am thinking that the kids could achieve herd immunity with very few deaths. Of course, any old person living with kids would have a large chance of dying (maybe more than 5% if over 70).
      - 9nGQluzmnq3M 6y ago
        There aren't a whole lot of multigenerational households in Sweden. Of course, grandparents do spend time with their grandchildren, but rarely 24/7.
  - jahaja 6y ago
    > Worth noting also that Sweden has the 6th highest case fatality rate in Europe (other Nordic countries are near the bottom of that list). It's very hard to make any proper comparisons of numbers before this has run its course. What if Sweden doesn't have a second wave but other countries do?
    - tonyedgecombe 6y ago
      Yes, I suspect this debate will be going on for years.
  - brutusmcforce 6y ago
    Yeah, I'm swedish and we are very much self-isolating. We didn't close schools, our idiot state epidemiologist didn't think nursing staff should use masks etc. so lots of elderly got infected. Stockholm infection numbers are insane, and we are probably getting there up north soon too. Lots of small businesses are defaulting. I'm trying to support my local restaurant by eating lunch there every day. All in all, it's a mess.
    - throwlaplace 6y ago
      One could even say the swedish are experiencing stockholm syndrome right now...
    - orblivion 6y ago
      Did they close bars and indoor dining?
      - brutusmcforce 6y ago
        Gatherings over 50 persons are prohibited, many bars and restaurants have went bankrupt though so I guess it's self-regulating.
- btmorex 6y ago
  I feel like Sweden's approach is a red herring. Everything I've read suggests that life in Sweden right now is very similar to other countries with more restrictive lockdowns. Like restaurants/shops haven't been forced to close, but many have closed anyway because business is down 80-90%. And they're definitely not going to get to herd immunity any time soon. The percentage of people exposed to SARS-CoV-2 in Stockholm is only slightly higher than New York City.
- joubert 6y ago
  Some info that I hope can help inform: * C19 deaths per million people (Sweden vs. Others, but you can configure for your favorite jurisdiction) - https://ourworldindata.org/grapher/total-covid-deaths-per-million?tab=chart&year=2020-05-08&country=OWID_WRL+SWE+USA+ZAF+NOR+NLD+DEU+GBR+CAN https://ourworldindata.org/grapher/total-covid-deaths-per-mi... * Architect of Sweden's no-lockdown strategy insists it will pay off - https://www.ft.com/content/a2b4c18c-a5e8-4edc-8047-ade4a82a548d https://www.ft.com/content/a2b4c18c-a5e8-4edc-8047-ade4a82a5... (I disagree that intentionally sacrificing people like this is the moral thing to do)
  - CubsFan1060 6y ago
    If the approach is accurate,then the deaths per million should even out over time (barring effective treatment discovery or a vaccine being approved earlier than thought). As I understand it (which is poorly), they are front-loading the deaths instead of a lockdown. I won't touch on the moral side of things. Edit: Replaced "correct" with "accurate". Can't come up with quite the right word there.
goalieca 6y ago
I think herd immunity is an interesting point. Sweden is not there yet but its effective R value has already dropped below 1 a while back and it will continue to drop as the susceptible population continues to shrink. Then there’s approaches like shielding that are interesting that are being discussed a lot. https://www.nature.com/articles/s41591-020-0895-3 https://www.nature.com/articles/s41591-020-0895-3 There’s something to note about this virus infection fatality rate: we don’t seem to have an agreed upon value for it and there is quite a window. It may depend on locale, population health, age, etc. But the 1% for the diamond princess is quite high and I think that number was cited for caution.
- rihegher 6y ago
  The diamond princess fatality rate has been revised and is now around 1.5%
- nodamage 6y ago
  > But the 1% for the diamond princess is quite high and I think that number was cited for caution. Why? The Diamond Princess has had 14 fatalities out of 712 cases which implies a fatality rate of 2%, with 8 unresolved cases still in the hospital that could push it even higher.
  - enitihas 6y ago
    The diamond princess was a very high age group though, very far away from the general population average age.
    - iso947 6y ago
      Not the staff, which are usually about half the people on a cruise liner.
      - enitihas 6y ago
        Fair enough. But is there data available separately for staff and passengers?
StavrosK 6y ago
Why would it? Everyone is trying to avoid getting infected (and dying). Isn't that what we should do? Herd immunity means "it's killed as many people as it could".
- Symmetry 6y ago
  No, it means that "enough people have been infected that each new infection causes less than 1 infection." Lets say we're in the middle of an outbreak and reach herd immunity. The infected people are still going to infect others, just less than the number currently infected. And then those people go on to infect an even smaller number. And so on. This is called "overshoot" and can end up being a significant number of people. One of the reasons for the "flatten the curve" heard immunity strategy is that it limits overshoot as well as reducing strain on medical facilities.
  - StavrosK 6y ago
    I see, thanks for the clarification.
- julianlam 6y ago
  Yes and no. the theory behind flattening the curve is to try and plateau the infection rates so that hospitals do not become overwhelmed. If we are going to be in a situation where hospitals have ample capacity, and we figure out a way to combat the symptoms of covid-19 without loss of life, then social distancing restrictions would be lifted immediately.
  - StavrosK 6y ago
    "Flattening the curve" is different from "herd immunity", though. You can have herd immunity without flattening the curve.
  - oefrha 6y ago
    I for one don’t fancy playing the Russian roulette even if hospitals have ample capacity and world class treatment, so I will distance myself the hell away and protect myself the best I could when I have to face people until this whole thing is over.
gshdg 6y ago
We still don’t even know whether immunity to this lasts more than a few months (as is common with other coronaviruses). So it’s premature to talk about herd immunity regardless.
- Gwypaas 6y ago
  SARS, another corona virus immunity lasts for 3-4 years on average with some cases up to 11 years. So it wouldn't be surprising at all with at least 1-3 years of immunity for people who had more serious infections.
  - Simon_says 6y ago
    How could this possibly be known? The first case was in 2002, and the last case was in 2004.
    - Gwypaas 6y ago
      Because you can study the response without having the disease in the wild. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115611/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115611/
      - Simon_says 6y ago
        That's a nice article. Thanks for responding. The 3-4 year timeframe you mention isn't in there. Is there another source for that?
        Gwypaas 6y ago
        I've seen it mentioned with sources on /r/COVID19 a bunch of times. I think this is the study they might have been referring to? And this is antibodies, not the memory cells mentioned above. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/
  - gshdg 6y ago
eiji 6y ago
With this mindset and approach the US will continue to have 20 million + unemployed all the way through Christmas.
- Symmetry 6y ago
  I don't think that people are going to hurry to go back to restaurants while the pandemic is active, official lockdown or not.
  - guscost 6y ago
    If anyone knows how to get a small dose of SARS-CoV-2 in a controlled manner today, please let me know. I'm not joking, I want this thing done as soon as possible, and I'm healthy enough where it's no problem. Sign up for challenge trials if you want to get in line: https://1daysooner.org https://1daysooner.org
  - sershe 6y ago
    Or maybe they will? https://time.com/5834087/shanghai-disneyland-sellout/ https://time.com/5834087/shanghai-disneyland-sellout/
- draw_down 6y ago
  Well, that, plus people will get sick and die
  - TheOtherHobbes 6y ago
    If no lockdown happened, critical workers would have become sick and/or died, critical systems would have started failing - temporarily, but it's still not a good look when there's panic buying and no food in the stores - and a significant number of people would have stayed at home anyway. Plus bodies. So many bodies. They would have skewed older, but it's completely wrong to say this is a disease of the over-70s. There are a lot of people of working age who barely survived infection and now have semi-permanent or possibly permanent - no one knows yet - lung damage. The idea that we could have somehow managed this without any economic damage is pure fantasy. It has no absolutely foundation in reality.
taneq 6y ago
Anyone could have told you that. Or rather, anyone could have told you that if we make some attempt at 'slowing the curve' in order to try and keep the number of ICU-requiring cases below the number of available ICU beds then it will take years if not decades to achieve herd immunity. You could just go for broke, let everyone catch it at once, and RIP 5-10% of your population. Even then it'll take most of a year to run its course and that year will be much, MUCH worse than just not being able to go to the pub or get a manicure.
- Pfhreak 6y ago
  Also, we'd probably see other effects too from the folks who survived but now have scarring in their lungs or increased risk of blood clots. Not a pretty picture.
  - taneq 6y ago
    Yeah, it's scary how much evidence is building that this virus leaves long term or permanent damage in a significant fraction of survivors. Also the next thing that comes along (and as our human monoculture grows, that will happen more and more frequently) might be much scarier. I feel like the silver lining to our current situation is that it's forcing us to set up our society to limit contagion so that when we do run across a new pathogen which is highly contagious, has a long incubation time, and is highly deadly, maybe we'll stand a chance.
    - TheOtherHobbes 6y ago
      If you want to lose sleep, consider what would have happened if this had been something really nasty, like airborne Ebola. Covid is actually not a highly deadly virus and on balance we've handled it quite poorly "because economics." There are much nastier pathogens we might have to deal with in the future.
      - taneq 6y ago
        Sssssh COVID-19 is super scary and we need to set our society up to deal with scary pathogens because of it. Right now. We'll figure out the economics later. /nod (Well just warning them beforehand didn't work so let's use this to get the ball rolling, huh?)
alpineidyll3 6y ago
It's interesting to compare how the world reacted to AIDS which is still a pandemic. Before the hiv was understood in detail, policy responses were blunt or non-existent. Many kids including myself were taught to abstain from sex entirely, which of course is a policy which would work on paper but with which no one can comply in practice. Here in Texas our lockdown has has little effect on the viruses rate of transmission. I believe that's because like many southern states, we could never achieve good compliance. More realistic policies which take into account the fact that young people are at far less risk for the virus will likely win the day. We can better support and sustain quarantine if it's triaged for those at greatest risk. Instead it Looks like policymakers will just let go of trying to control this in the US, and many older people will die unnecessarily.
- gwd 6y ago
  > Here in Texas our lockdown has has little effect on the viruses rate of transmission. What makes you say that? (Genuine question, not a challenge.) This website shows the estimated Rt going from a peak of 2.08 down to below 1, before stabilizing at 1.06: https://www.covidactnow.org/us/tx https://www.covidactnow.org/us/tx 1.06 is still > 1 which is bad, but it's certainly a lot better than 2. EDIT: Rt, not R0
  - alpineidyll3 6y ago
    Well, I was eyeballin' off a log-log plot, which is admittedly much less precise than your link. Even on that plot though R dips before we even officially shut down (Texas' cases were probably mostly imported from LA and elsewhere, and cut down by travel ending before we had an order in place) I'm also concerned that the law currently is at variance with the reality that the parks are full here in Austin. Instead of rushing to be open, I wish the government would tailor it's message to people who need it, and come up with 'clean' food/resource pathways for people who are vulnerable to this virus rather than trying to keep kids out of the water.
ravenstine 6y ago
I'm trying to figure out if this article is actually saying anything or saying effectively nothing. > Even in hotspots like New York City that have been hit hardest by the pandemic, initial studies suggest that perhaps 15-21%6,7 of people have been exposed so far. (goes on to mention how many people are dying) > Some have entertained the idea of “controlled voluntary infection,”9 akin to the “chickenpox parties” of the 1980s. However, COVID-19 is 100 times more lethal than the chickenpox. (goes on to completely dismiss whether that would actually lead to some level of herd immunity) I get that the disease is more deadly. But is this one of those cases where it's better to pull hard and rip the band-aid off in one go? Nobody seems to really want to broach this topic seriously. > To reach herd immunity for COVID-19, likely 70% or more of the population would need to be immune. Without a vaccine, over 200 million Americans would have to get infected before we reach this threshold. Put another way, even if the current pace of the COVID-19 pandemic continues in the United States – with over 25,000 confirmed cases a day – it will be well into 2021 before we reach herd immunity. If current daily death rates continue, over half a million Americans would be dead from COVID-19 by that time. It's unclear to me whether the author is stating that herd immunity would take too long under the condition that we completely opened up the global economy or if we all continued to stay isolated. We're definitely not going to reach 70% with the way things are.
- whyhow 6y ago
  >I get that the disease is more deadly. But is this one of those cases where it's better to pull hard and rip the band-aid off in one go? Nobody seems to really want to broach this topic seriously. If you "rip off the band-aid" then hospitals will be overrun and more people will die because they couldn't get adequate care. The idea is to slow transmission until we get better treatments or even a vaccine developed.
- Michael_Murray 6y ago
  We have talked about “pull off the bandaid”- to have 200M people get the disease means we’re going to lose somewhere between 1-2M people (just in the US). Doing that quickly means hospitals and morgues overflowing with dead from COVID. We HAVE talked about this from the beginning - this is the point of “flattening the curve”. If we let a million Americans die in a short time, it’ll tank the economy and overwhelm our healthcare system and ability to treat not only this disease but all others at the same time. It’d be one thing if we were testing and tracing to try and limit. But this YOLO strategy is a recipe for complete chaos. Even more inportantly: we don’t understand the long term impacts for those who survive. What is the 5-year mortality rate from complications? The US DOD has already decided that COVID infection disqualifies you for future military service (ostensibly because of the lung complications, but they haven’t said why formally yet). The YOLO strategy that some folks are proposing is insane given how much we don’t know about this disease. It would be like proposing in 1982 that we get everyone infected with AIDS so we had “herd immunity”. Think about how that would have worked out for us... and then tell me that it’s a good idea to do it this time. There may be a time when we know enough to make smart risk decisions about this disease, but less than 6 months after emergence isn’t it.
somewhereoutth 6y ago
Herd Immunity would seem a dangerous strategy or objective bearing in mind the following: - Immunity may only last a short time, in common with other Coronaviruses. Re-infection may be less severe, more severe, or not possible. We don't know. - Infection Fatality Rate is uncertain, but could be as high as 1%. - Long term health effects are unknown, but for example some evidence suggests permanent lung damage is possible. Significant areas of the globe have successfully suppressed the virus, and may even be looking towards eradication. Such countries are looking to establish 'travel bubbles' or 'green zones' between them and get back to normal (within their virus free spheres). For other areas, it may be too late for suppression, or for societal reasons suppression may never have been practicable, in which case herd immunity as an idea could be considered a palliative.
- nabla9 6y ago
  > Immunity may only last a short time, in common with other Coronaviruses Where you get this information? I seem to recall exact opposite. Coronaviruses mutate slowly and immune responses last several years. For four seasonal coronaviruses the immunity lasts 1-2 years, longer than other viruses causing influenza.
  - svd4anything 6y ago
    http://www.columbia.edu/~jls106/galanti_shaman_ms_supp.pdf http://www.columbia.edu/~jls106/galanti_shaman_ms_supp.pdf
guscost 6y ago
> Even in hotspots like New York City that have been hit hardest by the pandemic, initial studies suggest that perhaps 15-21%6,7 of people have been exposed so far. That's people with antibodies, not necessarily everyone who was exposed. There is zero information on seroconversion rates for mild and asymptomatic cases. We need to PCR-test a huge random sample, then follow up later with a serosurvey. Why are we not studying this? And why does nobody ever write a disclaimer listing their assumptions when making authoritative proclamations like this? It's going to shred their credibility into dust by the time this is all over, even if half of their assumptions turn out to be correct. Another study suggests that 20% infected could be enough for herd immunity, if individual variation in susceptibility is similar to the estimate for SARS-CoV-1: https://www.medrxiv.org/content/10.1101/2020.04.27.20081893v1 https://www.medrxiv.org/content/10.1101/2020.04.27.20081893v...
apatters 6y ago
The epidemiologists at JHU certainly understand this stuff better than I do, but a couple things about this article stood out to me. Is there an epidemiologist out there who could comment? - The herd immunity threshold depends on the reproduction number of the disease (R0). There's a basic reproduction number which is the rate they expect based on properties of the virus, and an effective reproduction number which is what ends up happening in reality. When effective R<1 the virus starts to die out. - The basic number can't be changed but the effective number can be changed dramatically. Lockdowns and social distancing have already changed it, with varying levels of success in different locations. - I have seen numbers thrown around that peg the herd immunity threshold for COVID-19 at 50-70%. This number is actually influenced by R, the lower R is, the lower your herd immunity threshold goes. JHU uses 70% here and that's the most pessimistic estimate I have seen. - Wouldn't good, sustained social distancing lower effective R and thus produce a herd immunity threshold lower than 70%, perhaps much lower? - New York is at 15-20% exposure already. I read this article from the Oxford Centre for Evidence-Based Medicine a while back which observed that the early estimates for epidemics and pandemics are invariably worse than what ends up happening in reality, and it got me thinking. https://www.cebm.net/covid-19/global-covid-19-case-fatality-rates/ https://www.cebm.net/covid-19/global-covid-19-case-fatality-... My personal bias is that I don't believe it is even possible, let alone wise, to keep people locked down on the time scales that are needed for controlling this virus, so they just kick the can down the road. But unprecedented levels of social distancing might be possible if we are smart enough. Every single person who works from home, wears a mask, or keeps their distance in public is helping.
badestrand 6y ago
In the article that section about the cruise ship talked about voluntary self-infecting and how that would be risky (1-2% death rate). What this completely ignores is that obviously only young and healthy people would attend those "corona parties" and thus the CFR of the voluntaries would rather be around 0%. And obviously those people wouldn't immediately go see grandpa but instead self-isolate for three weeks. I hate that so many are pretending that it's like russian roulette when in reality the odds are so highly skewed.

64 points by arunbahl 6y ago

josefresco 6y ago

I would liked to have read their opinions on Sweden.

lucideer 6y ago
Do you live in Sweden? A lot of people seem to be using it as some example of a country who haven't introduced lockdown measures, whereas in reality they are actually self-isolating and social distancing, just like everyone else. Worth noting also that Sweden has the 6th highest case fatality rate in Europe (other Nordic countries are near the bottom of that list).
- josefresco 6y ago
  I don't, but I've read enough to be aware of their approach which is to socially distance, protect the vulnerable but other than that, operate on a semi-normal basis. Kids go to school, adults go to work. Just wondering if they project Sweden to have any sort of "herd immunity" in the short/medium/long term timeframe.
  - irchans 6y ago
    I imagine that a large percentage (maybe 10%, maybe more) of the children in Sweden have been infected because they have more daily contacts and they "work" in crowded rooms. I am thinking that the kids could achieve herd immunity with very few deaths. Of course, any old person living with kids would have a large chance of dying (maybe more than 5% if over 70).
    - 9nGQluzmnq3M 6y ago
      There aren't a whole lot of multigenerational households in Sweden. Of course, grandparents do spend time with their grandchildren, but rarely 24/7.
- jahaja 6y ago
  > Worth noting also that Sweden has the 6th highest case fatality rate in Europe (other Nordic countries are near the bottom of that list). It's very hard to make any proper comparisons of numbers before this has run its course. What if Sweden doesn't have a second wave but other countries do?
  - tonyedgecombe 6y ago
    Yes, I suspect this debate will be going on for years.
- brutusmcforce 6y ago
  Yeah, I'm swedish and we are very much self-isolating. We didn't close schools, our idiot state epidemiologist didn't think nursing staff should use masks etc. so lots of elderly got infected. Stockholm infection numbers are insane, and we are probably getting there up north soon too. Lots of small businesses are defaulting. I'm trying to support my local restaurant by eating lunch there every day. All in all, it's a mess.
  - throwlaplace 6y ago
    One could even say the swedish are experiencing stockholm syndrome right now...
  - orblivion 6y ago
    Did they close bars and indoor dining?
    - brutusmcforce 6y ago
      Gatherings over 50 persons are prohibited, many bars and restaurants have went bankrupt though so I guess it's self-regulating.
btmorex 6y ago
I feel like Sweden's approach is a red herring. Everything I've read suggests that life in Sweden right now is very similar to other countries with more restrictive lockdowns. Like restaurants/shops haven't been forced to close, but many have closed anyway because business is down 80-90%. And they're definitely not going to get to herd immunity any time soon. The percentage of people exposed to SARS-CoV-2 in Stockholm is only slightly higher than New York City.
joubert 6y ago
Some info that I hope can help inform: * C19 deaths per million people (Sweden vs. Others, but you can configure for your favorite jurisdiction) - https://ourworldindata.org/grapher/total-covid-deaths-per-million?tab=chart&year=2020-05-08&country=OWID_WRL+SWE+USA+ZAF+NOR+NLD+DEU+GBR+CAN https://ourworldindata.org/grapher/total-covid-deaths-per-mi... * Architect of Sweden's no-lockdown strategy insists it will pay off - https://www.ft.com/content/a2b4c18c-a5e8-4edc-8047-ade4a82a548d https://www.ft.com/content/a2b4c18c-a5e8-4edc-8047-ade4a82a5... (I disagree that intentionally sacrificing people like this is the moral thing to do)
- CubsFan1060 6y ago
  If the approach is accurate,then the deaths per million should even out over time (barring effective treatment discovery or a vaccine being approved earlier than thought). As I understand it (which is poorly), they are front-loading the deaths instead of a lockdown. I won't touch on the moral side of things. Edit: Replaced "correct" with "accurate". Can't come up with quite the right word there.

goalieca 6y ago

I think herd immunity is an interesting point. Sweden is not there yet but its effective R value has already dropped below 1 a while back and it will continue to drop as the susceptible population continues to shrink. Then there’s approaches like shielding that are interesting that are being discussed a lot. https://www.nature.com/articles/s41591-020-0895-3 https://www.nature.com/articles/s41591-020-0895-3 There’s something to note about this virus infection fatality rate: we don’t seem to have an agreed upon value for it and there is quite a window. It may depend on locale, population health, age, etc. But the 1% for the diamond princess is quite high and I think that number was cited for caution.

rihegher 6y ago
The diamond princess fatality rate has been revised and is now around 1.5%
nodamage 6y ago
> But the 1% for the diamond princess is quite high and I think that number was cited for caution. Why? The Diamond Princess has had 14 fatalities out of 712 cases which implies a fatality rate of 2%, with 8 unresolved cases still in the hospital that could push it even higher.
- enitihas 6y ago
  The diamond princess was a very high age group though, very far away from the general population average age.
  - iso947 6y ago
    Not the staff, which are usually about half the people on a cruise liner.
    - enitihas 6y ago
      Fair enough. But is there data available separately for staff and passengers?

StavrosK 6y ago

Why would it? Everyone is trying to avoid getting infected (and dying). Isn't that what we should do? Herd immunity means "it's killed as many people as it could".

Symmetry 6y ago
No, it means that "enough people have been infected that each new infection causes less than 1 infection." Lets say we're in the middle of an outbreak and reach herd immunity. The infected people are still going to infect others, just less than the number currently infected. And then those people go on to infect an even smaller number. And so on. This is called "overshoot" and can end up being a significant number of people. One of the reasons for the "flatten the curve" heard immunity strategy is that it limits overshoot as well as reducing strain on medical facilities.
- StavrosK 6y ago
  I see, thanks for the clarification.
julianlam 6y ago
Yes and no. the theory behind flattening the curve is to try and plateau the infection rates so that hospitals do not become overwhelmed. If we are going to be in a situation where hospitals have ample capacity, and we figure out a way to combat the symptoms of covid-19 without loss of life, then social distancing restrictions would be lifted immediately.
- StavrosK 6y ago
  "Flattening the curve" is different from "herd immunity", though. You can have herd immunity without flattening the curve.
- oefrha 6y ago
  I for one don’t fancy playing the Russian roulette even if hospitals have ample capacity and world class treatment, so I will distance myself the hell away and protect myself the best I could when I have to face people until this whole thing is over.

gshdg 6y ago

We still don’t even know whether immunity to this lasts more than a few months (as is common with other coronaviruses). So it’s premature to talk about herd immunity regardless.

Gwypaas 6y ago
SARS, another corona virus immunity lasts for 3-4 years on average with some cases up to 11 years. So it wouldn't be surprising at all with at least 1-3 years of immunity for people who had more serious infections.
- Simon_says 6y ago
  How could this possibly be known? The first case was in 2002, and the last case was in 2004.
  - Gwypaas 6y ago
    Because you can study the response without having the disease in the wild. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115611/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115611/
    - Simon_says 6y ago
      That's a nice article. Thanks for responding. The 3-4 year timeframe you mention isn't in there. Is there another source for that?
      - Gwypaas 6y ago
        I've seen it mentioned with sources on /r/COVID19 a bunch of times. I think this is the study they might have been referring to? And this is antibodies, not the memory cells mentioned above. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/
- gshdg 6y ago

eiji 6y ago

With this mindset and approach the US will continue to have 20 million + unemployed all the way through Christmas.

Symmetry 6y ago
I don't think that people are going to hurry to go back to restaurants while the pandemic is active, official lockdown or not.
- guscost 6y ago
  If anyone knows how to get a small dose of SARS-CoV-2 in a controlled manner today, please let me know. I'm not joking, I want this thing done as soon as possible, and I'm healthy enough where it's no problem. Sign up for challenge trials if you want to get in line: https://1daysooner.org https://1daysooner.org
- sershe 6y ago
  Or maybe they will? https://time.com/5834087/shanghai-disneyland-sellout/ https://time.com/5834087/shanghai-disneyland-sellout/
draw_down 6y ago
Well, that, plus people will get sick and die
- TheOtherHobbes 6y ago
  If no lockdown happened, critical workers would have become sick and/or died, critical systems would have started failing - temporarily, but it's still not a good look when there's panic buying and no food in the stores - and a significant number of people would have stayed at home anyway. Plus bodies. So many bodies. They would have skewed older, but it's completely wrong to say this is a disease of the over-70s. There are a lot of people of working age who barely survived infection and now have semi-permanent or possibly permanent - no one knows yet - lung damage. The idea that we could have somehow managed this without any economic damage is pure fantasy. It has no absolutely foundation in reality.

taneq 6y ago

Anyone could have told you that. Or rather, anyone could have told you that if we make some attempt at 'slowing the curve' in order to try and keep the number of ICU-requiring cases below the number of available ICU beds then it will take years if not decades to achieve herd immunity. You could just go for broke, let everyone catch it at once, and RIP 5-10% of your population. Even then it'll take most of a year to run its course and that year will be much, MUCH worse than just not being able to go to the pub or get a manicure.

Pfhreak 6y ago
Also, we'd probably see other effects too from the folks who survived but now have scarring in their lungs or increased risk of blood clots. Not a pretty picture.
- taneq 6y ago
  Yeah, it's scary how much evidence is building that this virus leaves long term or permanent damage in a significant fraction of survivors. Also the next thing that comes along (and as our human monoculture grows, that will happen more and more frequently) might be much scarier. I feel like the silver lining to our current situation is that it's forcing us to set up our society to limit contagion so that when we do run across a new pathogen which is highly contagious, has a long incubation time, and is highly deadly, maybe we'll stand a chance.
  - TheOtherHobbes 6y ago
    If you want to lose sleep, consider what would have happened if this had been something really nasty, like airborne Ebola. Covid is actually not a highly deadly virus and on balance we've handled it quite poorly "because economics." There are much nastier pathogens we might have to deal with in the future.
    - taneq 6y ago
      Sssssh COVID-19 is super scary and we need to set our society up to deal with scary pathogens because of it. Right now. We'll figure out the economics later. /nod (Well just warning them beforehand didn't work so let's use this to get the ball rolling, huh?)

alpineidyll3 6y ago

It's interesting to compare how the world reacted to AIDS which is still a pandemic. Before the hiv was understood in detail, policy responses were blunt or non-existent. Many kids including myself were taught to abstain from sex entirely, which of course is a policy which would work on paper but with which no one can comply in practice. Here in Texas our lockdown has has little effect on the viruses rate of transmission. I believe that's because like many southern states, we could never achieve good compliance. More realistic policies which take into account the fact that young people are at far less risk for the virus will likely win the day. We can better support and sustain quarantine if it's triaged for those at greatest risk. Instead it Looks like policymakers will just let go of trying to control this in the US, and many older people will die unnecessarily.

gwd 6y ago
> Here in Texas our lockdown has has little effect on the viruses rate of transmission. What makes you say that? (Genuine question, not a challenge.) This website shows the estimated Rt going from a peak of 2.08 down to below 1, before stabilizing at 1.06: https://www.covidactnow.org/us/tx https://www.covidactnow.org/us/tx 1.06 is still > 1 which is bad, but it's certainly a lot better than 2. EDIT: Rt, not R0
- alpineidyll3 6y ago
  Well, I was eyeballin' off a log-log plot, which is admittedly much less precise than your link. Even on that plot though R dips before we even officially shut down (Texas' cases were probably mostly imported from LA and elsewhere, and cut down by travel ending before we had an order in place) I'm also concerned that the law currently is at variance with the reality that the parks are full here in Austin. Instead of rushing to be open, I wish the government would tailor it's message to people who need it, and come up with 'clean' food/resource pathways for people who are vulnerable to this virus rather than trying to keep kids out of the water.

ravenstine 6y ago

I'm trying to figure out if this article is actually saying anything or saying effectively nothing. > Even in hotspots like New York City that have been hit hardest by the pandemic, initial studies suggest that perhaps 15-21%6,7 of people have been exposed so far. (goes on to mention how many people are dying) > Some have entertained the idea of “controlled voluntary infection,”9 akin to the “chickenpox parties” of the 1980s. However, COVID-19 is 100 times more lethal than the chickenpox. (goes on to completely dismiss whether that would actually lead to some level of herd immunity) I get that the disease is more deadly. But is this one of those cases where it's better to pull hard and rip the band-aid off in one go? Nobody seems to really want to broach this topic seriously. > To reach herd immunity for COVID-19, likely 70% or more of the population would need to be immune. Without a vaccine, over 200 million Americans would have to get infected before we reach this threshold. Put another way, even if the current pace of the COVID-19 pandemic continues in the United States – with over 25,000 confirmed cases a day – it will be well into 2021 before we reach herd immunity. If current daily death rates continue, over half a million Americans would be dead from COVID-19 by that time. It's unclear to me whether the author is stating that herd immunity would take too long under the condition that we completely opened up the global economy or if we all continued to stay isolated. We're definitely not going to reach 70% with the way things are.

whyhow 6y ago
>I get that the disease is more deadly. But is this one of those cases where it's better to pull hard and rip the band-aid off in one go? Nobody seems to really want to broach this topic seriously. If you "rip off the band-aid" then hospitals will be overrun and more people will die because they couldn't get adequate care. The idea is to slow transmission until we get better treatments or even a vaccine developed.
Michael_Murray 6y ago
We have talked about “pull off the bandaid”- to have 200M people get the disease means we’re going to lose somewhere between 1-2M people (just in the US). Doing that quickly means hospitals and morgues overflowing with dead from COVID. We HAVE talked about this from the beginning - this is the point of “flattening the curve”. If we let a million Americans die in a short time, it’ll tank the economy and overwhelm our healthcare system and ability to treat not only this disease but all others at the same time. It’d be one thing if we were testing and tracing to try and limit. But this YOLO strategy is a recipe for complete chaos. Even more inportantly: we don’t understand the long term impacts for those who survive. What is the 5-year mortality rate from complications? The US DOD has already decided that COVID infection disqualifies you for future military service (ostensibly because of the lung complications, but they haven’t said why formally yet). The YOLO strategy that some folks are proposing is insane given how much we don’t know about this disease. It would be like proposing in 1982 that we get everyone infected with AIDS so we had “herd immunity”. Think about how that would have worked out for us... and then tell me that it’s a good idea to do it this time. There may be a time when we know enough to make smart risk decisions about this disease, but less than 6 months after emergence isn’t it.

somewhereoutth 6y ago

Herd Immunity would seem a dangerous strategy or objective bearing in mind the following: - Immunity may only last a short time, in common with other Coronaviruses. Re-infection may be less severe, more severe, or not possible. We don't know. - Infection Fatality Rate is uncertain, but could be as high as 1%. - Long term health effects are unknown, but for example some evidence suggests permanent lung damage is possible. Significant areas of the globe have successfully suppressed the virus, and may even be looking towards eradication. Such countries are looking to establish 'travel bubbles' or 'green zones' between them and get back to normal (within their virus free spheres). For other areas, it may be too late for suppression, or for societal reasons suppression may never have been practicable, in which case herd immunity as an idea could be considered a palliative.

nabla9 6y ago
> Immunity may only last a short time, in common with other Coronaviruses Where you get this information? I seem to recall exact opposite. Coronaviruses mutate slowly and immune responses last several years. For four seasonal coronaviruses the immunity lasts 1-2 years, longer than other viruses causing influenza.
- svd4anything 6y ago
  http://www.columbia.edu/~jls106/galanti_shaman_ms_supp.pdf http://www.columbia.edu/~jls106/galanti_shaman_ms_supp.pdf

guscost 6y ago

> Even in hotspots like New York City that have been hit hardest by the pandemic, initial studies suggest that perhaps 15-21%6,7 of people have been exposed so far. That's people with antibodies, not necessarily everyone who was exposed. There is zero information on seroconversion rates for mild and asymptomatic cases. We need to PCR-test a huge random sample, then follow up later with a serosurvey. Why are we not studying this? And why does nobody ever write a disclaimer listing their assumptions when making authoritative proclamations like this? It's going to shred their credibility into dust by the time this is all over, even if half of their assumptions turn out to be correct. Another study suggests that 20% infected could be enough for herd immunity, if individual variation in susceptibility is similar to the estimate for SARS-CoV-1: https://www.medrxiv.org/content/10.1101/2020.04.27.20081893v1 https://www.medrxiv.org/content/10.1101/2020.04.27.20081893v...

apatters 6y ago

The epidemiologists at JHU certainly understand this stuff better than I do, but a couple things about this article stood out to me. Is there an epidemiologist out there who could comment? - The herd immunity threshold depends on the reproduction number of the disease (R0). There's a basic reproduction number which is the rate they expect based on properties of the virus, and an effective reproduction number which is what ends up happening in reality. When effective R<1 the virus starts to die out. - The basic number can't be changed but the effective number can be changed dramatically. Lockdowns and social distancing have already changed it, with varying levels of success in different locations. - I have seen numbers thrown around that peg the herd immunity threshold for COVID-19 at 50-70%. This number is actually influenced by R, the lower R is, the lower your herd immunity threshold goes. JHU uses 70% here and that's the most pessimistic estimate I have seen. - Wouldn't good, sustained social distancing lower effective R and thus produce a herd immunity threshold lower than 70%, perhaps much lower? - New York is at 15-20% exposure already. I read this article from the Oxford Centre for Evidence-Based Medicine a while back which observed that the early estimates for epidemics and pandemics are invariably worse than what ends up happening in reality, and it got me thinking. https://www.cebm.net/covid-19/global-covid-19-case-fatality-rates/ https://www.cebm.net/covid-19/global-covid-19-case-fatality-... My personal bias is that I don't believe it is even possible, let alone wise, to keep people locked down on the time scales that are needed for controlling this virus, so they just kick the can down the road. But unprecedented levels of social distancing might be possible if we are smart enough. Every single person who works from home, wears a mask, or keeps their distance in public is helping.

badestrand 6y ago

In the article that section about the cruise ship talked about voluntary self-infecting and how that would be risky (1-2% death rate). What this completely ignores is that obviously only young and healthy people would attend those "corona parties" and thus the CFR of the voluntaries would rather be around 0%. And obviously those people wouldn't immediately go see grandpa but instead self-isolate for three weeks. I hate that so many are pretending that it's like russian roulette when in reality the odds are so highly skewed.