Cyclic work-lockdown strategies

A group of scientists and economists has devised a simple, tunable strategy for achieving exponential decrease in the number of new cases of Covid-19 while partially reopening the economy — or so it seems to me. The simplest form of the strategy is to alternate between k consecutive days of work and 14 - k consecutive days of lockdown. Although I am reluctant to add to the cacophony of inexpert opinions on how to deal with the pandemic, I will say that the strategy obviously works in an epidemiologic sense if the number of workdays per two-week cycle is sufficiently small. Furthermore, it is obvious that the number of workdays can be adjusted in response to the number of new cases. However, it is not obvious that k can be set sufficiently high for the strategy to work in an economic sense. Modeling reported in the \text{medR}\chi\text{iv} preprint “Cyclic Exit Strategies to Suppress COVID-19 and Allow Economic Activity” indicates that k=4 is likely to be sufficiently small. In other words, it seems that people might work half-time (4 \times 10 = 40 hours per two-week period) while driving the number of new cases toward zero. I am not qualified to judge epidemiological models, but will note that the results make sense if it is indeed the case that there is a “three-day delay on average between the time a person is infected and the time he or she can infect others.”

To be perfectly clear, I have not become a true believer in a strategy addressed in a preprint. I am saying that we should reject the notion that the pandemic will end only with herd immunity. It is not irrational to say that there may be, in the absence of an effective vaccination program, practicable methods of preventing most people from being infected, and that we should keep looking for them.

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52 thoughts on “Cyclic work-lockdown strategies

  1. It is not sufficient to look to the mathematics for a model such as this. You also have to look at human psychology, and how people will respond.

    My guess is they will respond poorly to this cyclic idea. However, they will also respond poorly to a long term lockdown. So, yes, we need to come up with something.

    I’d say that, whatever we try, we need to be able to monitor it and adjust it, depending on how it works out.

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  2. Neil Rickert: It is not sufficient to look to the mathematics for a model such as this. You also have to look at human psychology, and how people will respond.

    My guess is they will respond poorly to this cyclic idea.

    I doubt that any locality in the United States would give work-lockdown cycles a try in advance of a second wave of infections. It is conceivable that public health officials would say, when cases are on the rise, “Look, you’re headed for another total lockdown. We have good reason to believe that you can keep people working half-time, and avoid economic devastation, if you initiate a work-lockdown cycle now.” I think a few cities would be receptive. If the results were good, then other localities might follow suit. But I’m actually not optimistic.

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  3. Tom English: I doubt that any locality in the United States would give work-lockdown cycles a try in advance of a second wave of infections. It is conceivable that public health officials would say, when cases are on the rise, “Look, you’re headed for another total lockdown. We have good reason to believe that you can keep people working half-time, and avoid economic devastation, if you initiate a work-lockdown cycle now.” I think a few cities would be receptive. If the results were good, then other localities might follow suit. But I’m actually not optimistic.

    It is not only people working that the economy requires, it needs people to spend money , ideally on a credit card.

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  4. China achieved virtual elimination of the virus in one month with strict lockdown. I think it’s a bad excuse other countries make when they say they can’t do the same thing. But it requires two things. Convincing leadership, and citizens caring about doing what is best for everyone and the country.

    But when your own president is the least cooperative person in the world , someone who inspires no sense of togetherness whatsoever, in fact who preaches hatred and division as his only tool, gee , I guess I can see the difficulty.

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  5. “We should reject the notion that the pandemic will end only with herd immunity”.

    I don’t see how anything else can happen (granting that herd immunity includes vaccination). If infections continue to occur, and we can’t sustainably get R0 (fitness, no less!) below 1, herd immunity is always being approached. Tuning work patterns is fine for people in work – but even they have to get there and back, drop their kids off at nursery or school, shop, etc.

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  6. phoodoo:
    China achieved virtual elimination of the virus in one month with strict lockdown. I think it’s a bad excuse other countries make when they say they can’t do the same thing.But it requires two things.Convincing leadership,and citizens caring about doing what is best for everyone and the country.

    You need every nation in the world to have the same. You must see how improbable that is? Many countries have sacrificed ‘convincing leadership’ for someone they can vote for. It’s a popular model.

    And even with the Chinese approach, it got out. In the future, it’ll get back in. You’ve got the ideal policy for squeezing out one corner of a waterbed.

    But when your own president is the least cooperative person in the world , someone who inspires no sense of togetherness whatsoever,in fact who preaches hatred and division as his only tool,gee , I guess I can see the difficulty.

    Trump is a goon, but this is a global issue.

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  7. phoodoo: China achieved virtual elimination of the virus in one month with strict lockdown. I think it’s a bad excuse other countries make when they say they can’t do the same thing.

    I agree with this, in principle, as long as any alternative vector for the virus is identified and ring-fenced as well (pangolins, overseas arrivals – testing, quarantining or both). Once the levels of infection are low enough, tracing and contact-tracing becomes doable. We’re learning how to do social distancing effectively and yet still being able to function adequately, socially and economically. It doesn’t have to be binary. Why not both?

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  8. And the pot of gold at the end of the rainbow – an effective vaccine – is still being sought!

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  9. Allan Miller: Trump is a goon, but this is a global issue.

    What would be the economic consequences of banning all international travel for thirty days, globally? (Practical arrangements for essential travel such as confirming negative tests before travelling.)

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  10. Alan Fox,

    Alan Fox: I agree with this, in principle, as long as any alternative vector for the virus is identified and ring-fenced as well (pangolins, overseas arrivals – testing, quarantining or both). Once the levels of infection are low enough, tracing and contact-tracing becomes doable. We’re learning how to do social distancing effectively and yet still being able to function adequately, socially and economically. It doesn’t have to be binary. Why not both?

    Well, this is exactly what China has done. They brought the numbers down dramatically, and now they are able to trace new cases much better, and control any small outbreaks more effectively. Things aren’t closed down, but they are just being diligent about monitoring. And people still wear face masks when in crowds. I think they had something like eleven cases last week, but they were able to keep that under control.

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  11. I reckon cyclic working is a useful way of flattening the curve, especially if combined with small, redundant teams, but it will not cause eradication.
    There’s all that other mixing that goes on, and even full lockdown has not led to eradication.
    Also, be wary of using the average times as the time that everyone takes; variance in time-course of disease will make cyclic working less effective: I am willing to bet that there will be a small subset of patients who continue to shed after they have ceased to be symptomatic.

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  12. What’s more important? “Exponential decrease in the number of new cases” or “reopening the economy”?

    And if the pandemic doesn’t end with or without herd immunity, then what? Kill the economy?

    Modeling is easy. Staking your life on your model is not. Hammurabi’s Code – just replace builder with modeler:
    If a builder builds a house for a man and does not make its construction firm, and the house which he has built collapses and causes the death of the owner of the house, that builder shall be put to death.
    If it causes the death of the son of the owner of the house, they shall put to death a son of that builder.
    If it causes the death of a slave of the owner of the house, he shall give to the owner of the house a slave of equal value.
    If it destroys property, he shall restore whatever it destroyed, and because he did not make the house which he builds firm and it collapsed, he shall rebuild the house which collapsed at his own expense.
    If a builder builds a house for a man and does not make its construction meet the requirements and a wall falls in, that builder shall strengthen the wall at his own expense.

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  13. Allan Miller,

    I should have explained that I gave only a crude sketch of the strategies, and that I expected readers to peruse the preprint.

    From the preprint: The strategy can be implemented when lockdown has succeeded in stabilizing the number of daily critical cases to a value that the health system can support. Hereafter when we say ‘lockdown’ we mean population-level quarantine at home, together with all other available interventions such as testing and social distancing.

    The basic idea is to keep the effective reproduction number R, defined as the average number of people infected by each infected individual, below 1. When R is below 1, the number of infected people declines exponentially, a basic principle of epidemiology.

    To reduce R below 1, we propose a cyclic schedule with k continuous days of work followed by n continuous days of lockdown. As shown below, 4 days of work and 10 days of lockdown is a reasonable cycle that allows a repeating 2-week schedule. Epidemiological measures should be used and improved throughout, including rapid testing, contact isolation and compartmentalization of workplaces and regions. The cyclic strategy can thus be considered as a component of the evolving policy toolkit that can be combined with other interventions.

    By “work days” we mean release from lockdown with strict hygiene and physical distancing measures on the same k weekdays for everyone. It can include the entire population including schools, except for quarantined infected individuals and people in risk groups who may be in quarantine. More conservatively, it can include workers in selected sectors of the economy. Remote work should be encouraged for sectors that can work from home.

    A staggered cyclic strategy is also predicted to be effective, in which the population is divided into two sets of households that work on alternating weeks, each with a k-work (14-k)-lockdown schedule (Fig 2 [attached to this comment]). The staggered strategy has the advantage that production lines can work throughout the month and transmission during workdays is reduced due to lower density, whereas the non-staggered strategy has the advantage that lockdown days are easier to enforce. The cyclic strategies reduce the mean R by two effects: restriction and anti-phasing. The restriction effect is a reduction in the time T that an infectious person is in contact with many others, compared to the situation with no lockdown. For example, a 4-day work: 10-day lockdown cycle reduces T to 2/7 T ≈ 0.3T.

    The anti-phasing effect uses the timescales of the virus against itself (Fig. 3). Most infected people are close to peak infectiousness for about 3-5 days, beginning ≈3 days after being exposed. A proper work-lockdown cycle, such as a 4-work:10-lockdown schedule, allows most of those infected during work days to reach maximal infectiousness during lockdown, and thus avoid infecting many others. Those with symptoms can be infectious for longer 10, but can be detected by their symptoms and remain hospitalized, isolated or (self-)quarantined along with their household members, preventing secondary infections outside the household. The staggered cyclic strategy can further reduce mean R by reducing density during work days, leading to lower transmission rates (Methods).

    There are two Rs in the analysis, one for the work period, and the other for the lockdown period. Caption of Figure 2 (attached): Staggered cyclic work-lockdown strategy in which the population is divided into two groups of households that work on alternating weeks. Shown is I(t) from the SEIR-Erlang deterministic model with mean latent period of 3 days and mean infectious period 4 days. Transmission rates in lockdown and work give R_L = 0.6 and R_W = 1.5 respectively. Density compensation is ϕ = 1.5 and non-compliance is 10% (see Methods).

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  14. DNA_Jock: Also, be wary of using the average times as the time that everyone takes; variance in time-course of disease will make cyclic working less effective: I am willing to bet that there will be a small subset of patients who continue to shed after they have ceased to be symptomatic.

    Are the models saying otherwise? I’ve only glanced at them, but I don’t think so.

    DNA_Jock: I reckon cyclic working is a useful way of flattening the curve, especially if combined with small, redundant teams, but it will not cause eradication.

    There’s all that other mixing that goes on, and even full lockdown has not led to eradication.

    Test-and-trace-and-quarantine is feasible only when the number of infections is small. Lockdown is supposed to get us to a point where test-and-trace-and-quarantine is feasible. The preprint indicates that total lockdown is not necessary.

    (Living in the United States, you should understand why I hyphenate. There’s a lot of talk about ramping up testing. But there’s relatively little mention of contact tracing, which is the responsibility of states and counties. The states and counties, unlike the federal government, are legally required to balance their budgets. They’re already laying off employees, and I have not heard of any plan for federal funding of staff for contact tracing and quarantine enforcement. So I do not believe that near-eradication is in the offing for the U.S.)

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  15. Nonlin.org: What’s more important? “Exponential decrease in the number of new cases” or “reopening the economy”?

    And if the pandemic doesn’t end with or without herd immunity, then what? Kill the economy?

    Your response is bizarre. The preprint is about striking a balance of epidemiologic and economic concerns. And yet you insist on either-or propositions.

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  16. Tom English,

    But what’s the endgame? Granted that R can be fiddled with, and this may be a sustainable way of fiddling with it, do you think this will lead to eradication? If not, we’re doing this forever – or until herd immunity is arrived at.

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  17. Tom English: Your response is bizarre. The preprint is about striking a balance of epidemiologic and economic concerns. And yet you insist on either-or propositions.

    Not bizarre at all if you understand modeling. What kind of modeling do you do where you do not assign relative weights to your desired outcomes?

    The very meaning of the word “balance” assumes weighing one against the other:
    balance
    [ˈbal(ə)ns]
    NOUN
    an even distribution of weight enabling someone or something to remain upright and steady.
    “she lost her balance and fell”
    synonyms:
    stability · equilibrium · steadiness · footing
    a situation in which different elements are equal or in the correct proportions.
    “the obligations of political balance in broadcasting” · [more]
    synonyms:
    fairness · justice · impartiality · egalitarianism · equal opportunity · parity · [more]
    an apparatus for weighing, especially one with a central pivot, beam, and two scales.
    synonyms:
    scale(s) · weighing machine · weighbridge
    a counteracting weight or force.
    synonyms:
    counterbalance · equipoise · counterweight · stabilizer · compensation · recompense · ballast · makeweight · countercheck

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  18. Allan Miller: But what’s the endgame? Granted that R can be fiddled with, and this may be a sustainable way of fiddling with it, do you think this will lead to eradication? If not, we’re doing this forever – or until herd immunity is arrived at.

    In the models, the values of R_W and R_L are constant over time. So there is no endgame, according to the models. In reality, testing-and-tracing-and-quarantining should become more effective as the number of infections declines, and R_W should decrease as a consequence. Oversimplifying somewhat, if R_W falls below 1, then lockdowns can be discontinued. (This ignores, among other things, the issue of whether there will be sufficient testing capacity when lockdowns end.)

    As far as I know, smallpox is the only infectious disease ever to have been eradicated. I’m afraid that what we have emerging in the U.S. is a half-assed suppression strategy that does not drive the effective R (not to be confused with R0) very low, but does drive it low enough to prevent herd immunity. As I understand it, epidemiologists say that there’s herd immunity when the proportion of the population with individual immunity is at least 1 – 1/R0. If, say, R0 is 3 and effective R is 1.3, and individual immunity lasts two years, then there never comes a time when 1 – 1/R0 = 2/3 of the population is immune. That is, herd immunity never occurs. Or so a toy model tells me. It is possible that, two years from now, the accumulated number of Covid-19 fatalities per million residents will be greater for the U.S. than for Sweden — and that Sweden will have herd immunity, while the U.S. does not.

    It is possible that a mediocre suppression strategy will cost us more in lives and chronic illness (too little is said about damage to hearts and kidneys of survivors) over the long term than would a strategy for achieving herd immunity without vaccination.

    In an article published yesterday, Ezra Klein said a lot of what I’ve been thinking about saying (using some distinctive phrases that I’ve had in mind — it’s uncanny). See We Don’t Have a President, or a Plan: “60 days into the coronavirus crisis, the White House does not have a plan, a framework, a philosophy, or a goal.”

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  19. Tom English,

    It is possible that, two years from now, the accumulated number of Covid-19 fatalities per million residents will be greater for the U.S. than for Sweden — and that Sweden will have herd immunity, while the U.S. does not.

    That’s an interesting thought. What’s the opposite of a sweet spot?

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  20. There is a distinct ‘we can beat this’ element both to governmental and individual strategy. The hysteria accompanying every visible transgression, to the extent of vastly overestimating the likelihood of even the most trivial of infection possibilities, seems to be driven by a belief that if we all play our part, it will be gone. It’s a hard sell, the notion that it has to be endured, and people are bound to die. Nations that eradicate, or drive R very low, cannot stand alone forever.

    Our own government (which I nonetheless hold in contempt) did try to get that message out, but the main outcome is that ‘herd immunity’ has become a dirty word(s), an outcome that only people who care more about money than life would contemplate.

    Playing our part in that process is something we all want to avoid as individuals, naturally. Herd immunity is for other people to gain. In that spirit, I get far less bugged by ‘the twats’ than most of my compatriots – granting an offsetting concern for healthcare and mortuary services.

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  21. Allan Miller: The hysteria accompanying every visible transgression, to the extent of vastly overestimating the likelihood of even the most trivial of infection possibilities, seems to be driven by a belief that if we all play our part, it will be gone.

    Perhaps it’s a British thing. My experience is that, on my various sorties (yesterday I drove 180 km to collect a parcel that someone needed urgently. An adventure after two months of no farther than the nearest supermarket) people generally seem good-humoured, accepting the various ad-hoc arrangements for different venues and just getting on with it.

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  22. Alan Fox: Perhaps it’s a British thing. My experience is that, on my various sorties (yesterday I drove 180 km to collect a parcel that someone needed urgently. An adventure after two months of no farther than the nearest supermarket) people generally seem good-humoured, accepting the various ad-hoc arrangements for different venues and just getting on with it.

    People in person are invariably fine. We grin as we extravagantly step aside. But less directly, in posted notices or online, we’re seeing more frayed, panicky behaviour. I think it’s two different sets of people. People getting out are a self-selecting group who are generally more relaxed about risks, and endorphinised by the activity!

    On the other hand, I’m getting a flavour of a different world in the ‘mask wars’ in public spaces in the US.

    There’s some amusement to be had. On a loooong run on Wednesday, when I saw 6 people in 8 hours up the mountains, I came across a Covid sign saying ‘please don’t pet the pony or pebble the dog’. I’ve never pebbled a dog, but eventually concluded that ‘Pebble’ might be its name! Another sign urged me to not use any skin when opening a gate.

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  23. Tom English: It is possible that, two years from now, the accumulated number of Covid-19 fatalities per million residents will be greater for the U.S. than for Sweden — and that Sweden will have herd immunity, while the U.S. does not.

    Trying to understand how this can be. Is this the result of the US’s truly appalling resource allocation, both geographical (the local overwhelming that we have seen) and socio-economic (the large prison population comes to mind…)?

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  24. Allan Miller: On the other hand, I’m getting a flavour of a different world in the ‘mask wars’ in public spaces in the US.

    I’m not seeing that around here (Chicago suburbs). But it has been going on in some places.

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  25. Tom English: It is possible that, two years from now, the accumulated number of Covid-19 fatalities per million residents will be greater for the U.S. than for Sweden — and that Sweden will have herd immunity, while the U.S. does not.

    DNA_Jock: Trying to understand how this can be. Is this the result of the US’s truly appalling resource allocation, both geographical (the local overwhelming that we have seen) and socio-economic (the large prison population comes to mind…)?

    That particular remark of mine is wrong, and furthermore dangerously misleading. I’d accepted, uncritically, the popular notion that Sweden will achieve herd immunity. It takes just a wee bit of thought to see that if individual immunity results only from infection, and lasts only a limited time, then herd immunity is at best temporary. There must be continuing infections to keep the proportion of the population with individual immunity greater than 1 – 1/R0.

    Suppose, for simplicity, that R0 = 3, that individual immunity results only from infection, and that individual immunity lasts for exactly two years. Then the meaning of “herd immunity” is that at least two-thirds of the population has been infected in the past two years, and that many people are likely to be infected in the future. It is grossly wrong to speak of herd immunity in this scenario.

    I’ll hazard a guess that epidemiologists speak of herd immunity only when individual immunity is long-lasting.

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  26. Tom English: I’ll hazard a guess that epidemiologists speak of herd immunity only when individual immunity is long-lasting.

    Wrong. See What is Herd Immunity and How Can We Achieve It With COVID-19? (April 10, 2020), authored by two epidemiology professors:

    What will it take to achieve herd immunity with SARS-CoV-2?
    As with any other infection, there are two ways to achieve herd immunity: A large proportion of the population either gets infected or gets a protective vaccine. Based on early estimates of this virus’s infectiousness, we will likely need at least 70% of the population to be immune to have herd protection.

    > In the worst case (for example, if we do not perform physical distancing or enact other measures to slow the spread of SARS-CoV-2), the virus can infect this many people in a matter of a few months. This would overwhelm our hospitals and lead to high death rates.

    > In the best case, we maintain current levels of infection—or even reduce these levels—until a vaccine becomes available. This will take concerted effort on the part of the entire population, with some level of continued physical distancing for an extended period, likely a year or longer, before a highly effective vaccine can be developed, tested, and mass produced.

    > The most likely case is somewhere in the middle, where infection rates rise and fall over time; we may relax social distancing measures when numbers of infections fall, and then may need to re-implement these measures as numbers increase again. Prolonged effort will be required to prevent major outbreaks until a vaccine is developed. Even then, SARS-CoV-2 could still infect children before they can be vaccinated or adults after their immunity wanes. But it is unlikely in the long term to have the explosive spread that we are seeing right now because much of the population will be immune in the future.

    There’s nothing here to contradict what I’ve said. The authors are playing up the prospect of a vaccine. I still say that it is misleading to speak of herd immunity in the absence of long-term immunity in individuals.

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  27. Tom English,

    I still say that it is misleading to speak of herd immunity in the absence of long-term immunity in individuals.

    I don’t think so. As Jock says, there are shades of grey. A population in equilibrium with a pathogen has a distribution of individuals at different lengths of time since last infection. The interval may be significantly greater than the mutation interval of the pathogen, or even the lifetime of effective antibodies. Even at a given time-since-infection there will be differences in the antibodies carried due to stochastic differences in the binding to the pathogen surface. Thus when a mutation occurs and it starts to rise in the population, many individuals will still mount an immune response, perhaps experiencing mild symptoms, slowing the disease.

    There is additionally the factor that we have mused over relating to the possibility that immune systems are partially tuned by sub-infectious doses of common pathogens, raising ‘alertness’ without noticeable symptoms. The response of a population is much less severe with established pathogens, even mutating ones. I’d call that herd immunity.

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  28. Allan Miller: …I’d call that herd immunity.

    Fair enough, but (to hit a recurring theme) the underlying reality is unaffected by the words we use to describe it. Back in the pre-CoVid day, I used to think “herd immunity” was a description of the peculiar way that immuno-compromised people were protected by the vast swathes of regular, community-minded citizens surrounding them; now it’s become a political trope.
    Irony intended.

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  29. DNA_Jock: Fair enough, but (to hit a recurring theme) the underlying reality is unaffected by the words we use to describe it. Back in the pre-CoVid day, I used to think “herd immunity” was a description of the peculiar way that immuno-compromised people were protected by the vast swathes of regular, community-minded citizens surrounding them; now it’s become a political trope.
    Irony intended.

    I’m influenced by this, though I don’t know if it caught on. They use ‘herd effect’ for the phenomenon you describe, herd immunity for the antibody-bearing fraction, which makes some sense. It has, as you say, unfortunately become tainted as a term.

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  30. Alan Fox: I agree with this, in principle, as long as any alternative vector for the virus is identified and ring-fenced as well (pangolins, overseas arrivals – testing, quarantining or both). Once the levels of infection are low enough, tracing and contact-tracing becomes doable. We’re learning how to do social distancing effectively and yet still being able to function adequately, socially and economically. It doesn’t have to be binary. Why not both?

    I don’t really understand why eating different kinds of animals is a problem.

    Why are pangolins more likely to give people a virus than a chicken or a sheep?

    Mad cow disease I believe comes from cows.

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  31. phoodoo,
    I didn’t mention eating. Plague was caused by infection with a bacterium that normally existed in rodents but got into human populations from contact with fleas that lived on the rats.

    So plague spread. both by transmission from rats by fleas and by human contact. Isolation and immunity aren’t enough without also dealing with rats,.

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  32. The virus causing the current pandemic likely previously existed in another animal (bat’s and/or pangolins) so without preventing reinfection from such a reservoir, distancing cannot eliminate the virus..

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  33. Plus I was suggesting that social distancing in any limited region can only work if ringfenced against infected incomers who act as vectors harbouring the infection. Trace-and-test will help of course.

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  34. Allan Miller,

    DNA_Jock,

    I don’t mean to give the impression that I know more than I do. But I gave a primer on epidemiological modeling a quick going-over. Then I understood that, within the class of compartmental models, a SEIRS (susceptible, exposed, infectious, recovered, susceptible) model would be appropriate for SARS-CoV-2. Googling for a SEIRS model for SARS-CoV-2, my first hit was an article in the journal Science:

    Projecting the transmission dynamics of SARS-CoV-2 through the postpandemic period (14 April 2020).

    What I find particularly interesting is that the authors develop the model first for two relatively well understood betacoronaviruses, for which there is cross-immunity, and then add SARS-CoV-2 (another betacoronavirus) to the model, taking into account the possibility of further cross-immunity.

    One of the main findings:

    If immunity to SARS-CoV-2 is not permanent, it will likely enter into regular circulation

    Much like pandemic influenza, many scenarios lead to SARS-CoV-2 entering into long-term circulation alongside the other human betacoronaviruses (e.g., Fig. 3, A and B), possibly in annual, biennial, or sporadic patterns over the next five years (tables S2 to S4). Short-term immunity (on the order of 40 weeks, similar to HCoV-OC43 and HCoV-HKU1) favors the establishment of annual SARS-CoV-2 outbreaks, while longer-term immunity (two years) favors biennial outbreaks.

    It happened also that, reading the news, I saw this quotation:

    If natural immunity to this virus is going to be gone within three to six months, then we don’t even need to be talking about herd immunity,” Dowdy said.

    That’s “David Dowdy, an associate professor of infectious disease epidemiology at the Johns Hopkins Bloomberg School of Public Health.”

    It seemed to me that the duration of immunity had to be a critical consideration, and that talk about herd immunity is premature when we do not know how long individual immunity lasts. I’m sure now that some epidemiologists say the same. I suspect that most of them do. Of course, they have a much better idea of why they’re saying it than I do. My objective here is not to win an argument. It’s to persuade you to be careful about “herd immunity.”

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  35. I read just a couple days ago that CV19 immunity is broad and long lasting, and that immunity to one CV gives partial immunity to others.

    I didn’t bookmark it because it was one of those things requiring several confirming studies before believing.

    But other sources seem to say that this virus is unlikely to vary its way around immunity.

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  36. I’m hearing rumors that colleges and universities may be doing drastic cuts to programs. Specifically, Missouri Western eliminating majors in history and philosophy. But there are rumors that many colleges will simply close.

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  37. petrushka:
    I read just a couple days ago that CV19 immunity is broad and long lasting, and that immunity to one CV gives partial immunity to others.

    I didn’t bookmark it because it was one of those things requiring several confirmingstudies before believing.

    But other sources seem to say that this virus is unlikely to vary its way around immunity.

    I just read the sailors who tested recovered from the virus are now testing positive again.

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  38. petrushka,
    Curious as to the nature of the evidence that was used to support the claim that “CV19 immunity is broad and long-lasting“, given what the “19” stands for…

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  39. Vaccination has only been available as a strategy for a short period of our history. For many threats, it has not been successfully developed. Something – call it what you will – has nonetheless resulted in a persistent suppression of previous pandemic pathogens, despite the non-inheritance of immune responses, the low antibody count of mild illness and the sometimes short persistence of infection-induced IgG. It would be interesting to know what that ‘something’ is.

    It would be remarkable if Covid-19 was the first illness in our history for which vaccination was the only suppressive strategy, coinciding with a moment in time we had the ability to develop that strategy. So, although I hear the concerns about the efficacy of natural immunity, I am not overly pessimistic about them (my own opinion being less well-informed than some). The concern, of course, is that there could still be a high body count to get there.

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  40. petrushka,

    I am hearing rumors that the dumbest person on the planet is actually taking hydroxychloroquine as a prophylactic against getting the virus. I am sure it is fake news, but still the rumors I have heard are from the idiot himself (could be digital fakery).

    Here is the thing, if the rumors really are true, won’t someone get in serious trouble for giving this drug to infants?

    I am not sure if this particular infant’s brain could get any smaller, but still.

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  41. If the Orange Idiot manages to off himself by taking hydroxychloroquine every Irony Meter in the known universe will melt into slag. 😀 😀 😀

    1+
  42. I couldn’t get any chloroquine, but chloroquat is quite similar.

    0
  43. Allan Miller,

    When the turnip was talking about taking it, he couldn’t say the name, so instead he kept saying, the hydroxy stuff. I heard lots of good things about it. …

    0
  44. Joe Biden announces he is going to close the keystone pipeline if he gets elected.

    Who are his advisors? Why do they have zero common sense? OK, if he is going to close it then he can close it. What possible political benefit comes from his announcing this before the election? Is this going to get him voters who wouldn’t have voted for him before? What kind of votes would that be?

    On the overhand, would it turn off some voters who are in the middle but have jobs tied to pipelines?

    So why bother with this useless announcement? Is everyone in politics really this stupid?

    Please, let both of the candidates suffer an aneurysm sooner rather than later, so we they can just start all over and make America like a real country again.

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  45. phoodoo: Who are his advisors? Why do they have zero common sense? OK, if he is going to close it then he can close it. What possible political benefit comes from his announcing this before the election? Is this going to get him voters who wouldn’t have voted for him before? What kind of votes would that be?

    The votes from some people who view the pipeline as monumentally important as might be less than inspired by Biden and might vote for they Green candidate. So yes, they might not vote for him. It is aimed at his voters to solidify his voters.

    On the overhand, would it turn off some voters who are in the middle but have jobs tied to pipelines?

    Maybe because those voters do not exist? If job security on the pipeline is the number one priority, they are always going Trump.

    Please, let both of the candidates suffer an aneurysm sooner rather than later, so we they can just start all over and make America like a real country again.

    You registered to vote in the US?

    0

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