I'm an advocate of using computer models to help us think about what might or could happen during various pandemic flu scenarios, but it is a technique with drawbacks. For one, it can suggest that some things might be possible that are either very difficult to do or aren't feasible. This happened in 2005 when some models were published in Science and Nature that suggested a pandemic could be nipped in the bud before it started. Most people thought that what was required was unrealistic but it put WHO in a bind. They had to marshal their resources to show they were willing to try or go down valiantly. These models can also be misunderstood or some results taken out of a very nuanced context for a good headline. That's what has happened for a really interesting modeling exercise that was just published in the Proceedings of the National Academy of Sciences (PNAS).
Consider this Reuters story:
Pandemic flu plan would put Chicago on lockdown
By Julie Steenhuysen
CHICAGO (Reuters) - Containing an influenza pandemic in a large U.S. city like Chicago would require widespread school closings, quarantines of infected households and bans on public gatherings, U.S. researchers said on Monday.
But, if done quickly and well, such steps could reduce infections by as much as 80 percent, said researcher Stephen Eubank of Virginia Tech in Blacksburg, Virginia, based on a computer simulation of just such an event.
"If you implement it early and people comply, you can save a lot of people. You can make it look a lot more like a seasonal flu than the 1918 pandemic," said Eubank, referring to a global flu epidemic that started in 1918 and killed between 40 million and 100 million people. (Reuters)
The idea of Chicago in a "lockdown" is preposterous and not even remotely suggested in the story. So what was the story really about? It's really quite an interesting paper. Three groups used independently developed but very sophisticated computer models to gauge the impact of two very different sorts of pandemic flu interventions: medical interventions, like the use of antivirals (e.g., Tamiflu) either prophylactically for exposed persons or as treatment for those diagnosed with flu; and non-pharmceutical measures, like school closures, prohibiting public events and isolation of cases or quarantining their well family members. Using the same general range of assumptions, the three groups ran simulations and compared their results. The idea was to see how sensitive the outcomes were to the different kinds and implementations of the models for the same event. They tested several thresholds for when to wheel the measures into action, one as low as .01% of the population down with flu, ratcheting it up as high as 10%. If your city had 1,000,000 the low (.01%) end would start the interventions as soon as 100 cases were diagnosed in an outbreak, the high end (10%) wouldn't kick in until there were 100,000 cases. A 1% threshold would be 10,000 cases in a city of 1 million. In 1918 it is reported that Chicago had more cases than that in a single week in October.
The models are quite involved, with a large number of moving parts. Here's a sample:
School Closure. All schools, including primary, middle, and high schools, are closed at a particular threshold community cumulative illness attack rate. Once the schools are closed, children are expected to stay at home with a certain compliance rather than to increase community contacts. Compliance is modeled by the reduction in community contacts achieved--assumed to be 30%, 60%, or 90%. In the UW/LANL model, day care centers and small play groups of preschool children are also closed, and the same compliance rates apply. The other two models do not explicitly model day care centers and small play groups.
Liberal Leave Policy. All symptomatic individuals retire to the home from the workplace one day after becoming ill.
Workplace Social Distancing. At a particular threshold community cumulative illness attack rate, workplace contacts are reduced by a certain percent. In the baseline combination scenarios, the workplace contacts are reduced by 50%. Workplaces are not closed. Social distancing in the workplace might eventually be accomplished by staggering the arrivals of workers at work, encouraging people to work at home, or other measures. (Halloran et al., PNAS)
There's lots more to this paper and if you are interested you will find it fascinating and well within your reach. There are some technicalities but the gist is quite accessible, although it takes concentration to sort it all out. Without any intervention at all, and depending to some extent on the basic reproductive number, R0 (the average number of new cases each infective produces in a susceptible population), the proportion of the population eventually affected ranges from 40% to 60% (the latter with what is probably an unrealistically high R0 = 3.0). One intervention scenario, described as baseline, begins to intervene at a threshold of 1% of the population symptomatic, with 60% of the actual cases being counted. Everyone is treated with antivirals and all household members are prophylaxed. Schools but not workplaces are closed. Workplace absenteeism or transmission reduction is assumed to be 50%. Liberal leave policies are universal, however. If you are sick you stay home. Assuming compliance of a home quarantine for households with a case of flu and children staying home after schools are closed of only 30% (i.e., most people wouldn't comply) but a 60% compliance with isolation of those who are sick (meaning that 40% of the sick would be out and about to some extent), there is an 80% - 90% reduction at the lower and more likely R0 values (1.9 to 2.1). Even at fairly high R0 levels there is greater than a 50% knockdown of cases.
There didn't seem to be marked qualitative variation with these three different models. The application of targeted use of antivirals (treat cases and their household contacts), close schools and discourage children from going out into the community and encourage liberal sick leave policies go a surprisingly long way. This is not a mandatory quarantine and isolation order. There is no enforced "lockdown." On the contrary, it assumes that only 30% of the households with a sick person will not go out and about and only 60% of the sick will stay home. When a person gets sick they will leave work after one day of illness -- but only half the time. Other results in the paper show that lowering the threshold to .01% helps but not much. 1% seems like a reasonable threshold.
These are not mild interventions, to be sure, but if the R0 were in the expected region of 2.0, this much would reduce cases by more than 80% -- according to these models. But of course they aren't the real thing. They are scenarios inside a computer. So there is the obligatory disclaimer:
We caution against overinterpretation of the modeling results, even where the three models suggest similar effectiveness of interventions. Because of the uncertainties in the models, the results need to be viewed more as helping to structure thinking about pandemic planning, rather than being predictive of the precise effectiveness of different policies.
Nice to say this, although it is not at all clear exactly what it means. How are these results supposed to help us structure our thinking about pandemic planning? One thing it says to me is that it is conceivable much could be accomplished to slow a pandemic without mandatory and coercive policies. Martial law wouldn't be needed and in fact might be counter productive as people flee the authorities. Social pressure is much more likely to bring about the desired social distancing than is the National Guard (they are all in Iraq, anyway).
One thing for sure. People will need support if they are going to reduce their contact with each other in the community. There will need to be mechanisms to supply and care for households with sick people in them, adequate social sick leave policies, and some kind of accommodations made for working parents when schools are closed. In other words, we'll need a robust, working and effective public health and social service infrastructure. Without it, all the authorities will be able to do is preside over chaos. With it, we can conceivably get through some very rough times together.
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so, what's realistic ? 50% reduction of cases ?
That seems to be almost what could be achieved in 1918.
Without antivirals.
And, when they successfully managed the wave -
how long will they have to maintain measures ?
Remembering St.Louis 1918 with a 2nd peak,
when measures were lifted and the virus found the
non-immune population again.
The authors write this were for waiting for a vaccine,
which might come after 6-9 months.
Even assuming the vaccine will work - 6-9 months
of such measures is awful.
Quarantines of infected households if enforced by law suggests "Lockdown" to me. Also, if a household is to be quarantined, why the double standard for an office when a worker becomes symptomatic at work and has likely been infectious at work for 1-2 days.
Quarantines will not work, household or office, unless both are required to be quarantined, which is not workable. So close the schools and places of worship, eliminate public gatherings, require the use of masks in public, and do whatever you can do on a voluntary basis that makes some sort of sense.
A serious issue not even being addressed, is that people who are sick and do not work, for the most part do not get paid, and many people live paycheck to paycheck. This issue may force those with mild symptoms to continue working unless their is some moratorium on debt repayment for the duration of the emergency. And we know that won't happen.
I think people just need to stop being so fearful. Influenza pandemics are a natural occurrence, every 30 years or so. We need to try to minimize the pain when they hit, and if it can be prevented, great, yet nothing in our history suggests the ability to prevent such a natural event without draconian measures being imposed that in the end may cause more pain than they prevent.
The virus, if it got to pandemic status, will be endemic once it hits. Just like H3N2, H1N1, and like anon said, there will likely be multiple stages as in 1918, and the worst stage may not be the first one.
I doubt that any of their models with the current CFR would be realistic. It doesnt take enough things into account. I read the PNAS gig and came away with a less than comforting feeling. All three assume a lot of things and its the assumptions that skew the results.
Take it by line item. First they aint all in Iraq. Start with that one.
Next...Reduce contact with the community. Well interventions are one thing, but if there is a lockdown they are going to have to go out for food sooner or later. Mechanisms in place to care for the sick? There already. They will haul them out and place them in with other flu patients. There isnt going to be any home care and not one plan has that in place that I have seen except the "care of a loved one at home by a worker." If that worker is smart they'll not go home. How does a worker care for a loved one in a BF environment and not get sick themselves?
If you had 10,000 in a week do you think that anyone would place themselves into that amount of jeopardy? There would be some that would do it out of a higher honor but there just isnt that amount of equipment, or people to do it. So far it looks like to me that BF is a flyswatter anyway. You either get better or you go fairly quick. And what care could someone give or get? Maybe feeding them. Everything else is hospital level care. I dont want to throw cold water on this but its not reality.
Adequate social sick leave policy? You go out with BF you really go out for the fight of your life. Is that like a policy that says that if you go out we still have to pay you? The people have to take responsibility for themselves.
"Some kind of accommodations made for working parents when schools are closed. In other words, we'll need a robust, working and effective public health and social service infrastructure." The parents if they go to work might bring home the bug, If the schools are closed the parents are going to have to stay at home and period at that. Work? Revere, they plan to shut down just about everything until the danger passes. I cant see how in the world you could say robust, working and effective public health and social services infrastructure would help except in the most minimal of terms. Tell me what social worker is going to go into a known flu home? Tell me what hospital group in any major city that could handle 10,000 cases a week? Tell me where these human resources to do all of these things would come from? I cant see anything but the military and in full chem/bio gear. The Guard would be there because its their job. The active duty forces would be too, but I cant see any changes in the outcomes.
There isnt going to be a White Knight riding in for this and its impossible to capitalize for, even if UHC was in place. The Brit system already is straining, how could they or the Canucks handle even 5000 cases per week in their major metro areas? The hospitals are full now as it is pretty much everywhere here and there.
Then there is the treatment. That Chinese guy that made it last year spent a solid month in the hospital and couldnt walk for weeks after discharge. Who is going to provide services to these people under any social infrastructure?
Simple answer is that they're not. The USGovt has delegated by order of Congress the handling of BF to the States, with financial assistance from the Federal Government for pre-pandemic activities. There will be a valiant effort, followed by the Black Death of our time if its high CFR. There simply isnt any way to pay for it. Even if they threw all the money in the world at it, define what the change in the outcomes would be? 1 out of every 10 maybe? I would bet it would be less than that.
The models really didnt take all the variables into account either. They only looked at primary cause flu for deaths and there are plenty of other variables.
Is BF extinction or natural selection?
Randy: There's no lockdown. The assumption is 30% compliance on family members staying home, 60% on flu cases staying isolated. Hardly a lockdown. Half of children will still go out, even if school is closed. Work places will remain open. This is all scenario 2 stuff, which is the only thing I talked about. If you read the paper. you know there is a lot of other stuff I didn't talk about. No CFR was used since they weren't counting deaths, just cases. The assumption here is that people will be treated by family members at home, using antivirals and supportive care.
With all due respect to any researchers who engage in this type of work--including those who did this one--I just don't believe that it can happen this way. There are too many assumptions about coping mechanisms/systems which would need to be previously set in place. In a society where a huge percentage of meals are eaten in/from restaurants, and where we rely on "just in time" deliveries, there is no way, in my opinion, that this can work. Regarding the risk of pandemic flu and other natural disasters, we are a nation of grasshoppers, not ants.
If you look at the death rate in Philadelphia in 1918, for example (11,000 people in one month, at one point), you can see how just that one issue can throw any pandemic preparations off kilter. Those bodies came from individual homes--where other people were also sick--and had to be picked up or delivered--again often by sick people, and many via public transportation--to other locations in the city, where they were stacked until they could be handled. Society in 1918 handled death largely at home, and it was still a frequent occurrence. And remember, our current society isn't as emotionally prepared as society in 1918 to handled death either on that scale or in the manner required in a pandemic. (Mass graves, etc.)
Just a bit of trivia: the word "living room" was invented because of the horrendous grief associated with using a family's parlor for keeping the bodies of dead family members until after their funerals. This occurred after the Pandemic of 1918-19. Also, think about your American history textbook in high school. Even when I attended school--much later in the century--there was NO mention of the pandemic of 1918. Many families never again mentioned the pandemic which killed their family members, because the emotional trauma of losing so many in such a short time was so great.
It all sounds great, if you live "in that best of all possible worlds", but I just don't see how it can happen. AnnieRN
New York Times article this morning highlights the difficulty. Government in Hong Kong has ordered all schools in the territory closed following the deaths of three children during an outbreak of (SEASONAL) influenza. Hong Kong stock market plunged; parents are pissed. Here's the bit I found most illuminating:
"School systems in the United States sometimes close during seasonal influenza outbreaks, but typically wait until so many children and teachers have fallen ill that absenteeism is chronic and every child has already been exposed to the virus, said Dr. Arnold S. Monto, an epidemiologist at the University of Michigan."
AnnieRN: I would point out that you are also engaged in this kind of "research" when you suggest an alternative scenario. That's all the modelers are doing, specifying a scenario but doing it more explicitly than you are and seeing what happens, just as you are doing by waving your hands. Note that they are not making assumptions about individual mechanisms of reduced contact or transmissibility, but only saying, suppose one or the other is reduced by, say 40% by asking people with sick family members to stay home. They actually assume quite a lot of non-compliance and continued mixing of children if schools are closed. They are quite cautious about the predictive power. They are trying to get at a couple of different things. How much difference does using different models and different implementations make? Answer in this case is not as much as one might think. Also, how bad must R0 be before nothing much helps. Answer: unrealistically high (my interpretation). Of the various interventions, how far could you get, with a specific scenario (and six were considered of which I only discussed one, the least constraining) with targeted antivirals (not population based) and closing schools only and cancelling some public events). Answer: much farther than you might expect. There is not much I would consider implausible about any of their assumptions, although you can always argue about it. You really need to read the paper, if you haven't, because the news reports IMO are highly misleading and I think the quotes in them from the VMI researcher didn't help clarify things.
The important thing to remember about this is that you are doing just what they are doing but they are doing it in a highly systematic, structured and explicit way. So if you don't trust, believe or choose to rely on their method (as opposed to their conclusions), then you should also not trust, believe or rely on any of your own judgments, either. We are lost, then, because we are saying we can't anticipate anything. Instead we are just saying, "I think this is going to be really bad [although you think this because of an unspoken model] and I'm not going to change my mind by thinking it through further." I don't believe any of us want to move forward this way, or if we do, then there's not much left to talk about.
Racter: WSJ also has a good piece on this by Nick Zamiska. It is not clear the situation in HK is any worse than usual, but pediatric fatalities (of which there have been well over a hundred in the US, I believe) are always frightening. Our little grandson (10 months) got a flu shot (at my recommendation) because people always seem to forget that flu does kill people. It's not just a bad cold. When the vaccine is mismatched, that's a problem, but it doesn't happen that often and there is still likely residual protection, which can make the difference between really, really sick and just plain dead.
Regarding what we learn from these exercises, see my previous thoughts in response to AnnieRN's comment. My post was to try to clarify a little what I thought was a badly reported scientific paper of some interest.
Going just by the chart on the weekly CDC update, I make it roughly 32 pediatric fatalities so far this season. Is there a better source? As for residual protection, I assume that has to do with cross-reactivity; but it's tricky. If you start by establishing some neutralization threshold as the correlate of protection, and then say that failure to meet that threshold is not necessarily an indication that no immunity exists, then aren't you making a statement about how useful the threshold is as a correlate of protection, as much as anything?
The reality we're dealing with here is that bad reporting of scientific findings is as rampant as scientific illiteracy in the public to whom it "reports". Public health policy decisions cannot have any hope of succeeding unless they acknowledge this reality. I think we can anticipate this: wait until things are so bad that even the idiot public recognizes the danger, and it's too late to do anything about it. Impose measures too soon, and you risk becoming the "bad guy", and they'll quit listening to anything you say. I'm interested in hearing about solutions that make it easier for people to comply; for instance, what about the Hong Kong parents who can't miss work, and can't take their kids to work with them? If those kids end up packed into some kind of ad hoc child care centers, how is that any better than just leaving the schools open?
"If you don't trust, believe or choose to rely on their method (as opposed to their conclusions), then you should also not trust, believe or rely on any of your own judgments, either."
revere, I understand the virtues of modeling, but you've got yourself a bad case of scientism: 'if you don't trust the scientists, you can't trust yourself.' Boo.
Almost to a model, SIR and related treatments reduce social inputs to some combination of population density, age structure, transportation gravity, and social distancing. As AnnieRN pointed out, the basic realities of everyday life in America--I'll add here living check-to-check, eroded neighborhood life, etc.--nullify many of the model's assumptions and implications. The intensifying capitalist attack on working people over the past 30 years has fundamentally shifted the social geographies through which viruses spread.
Are there researchers out there prepared to incorporate these shifts? It need not be conscious corruption, but the funding streams emanating out of the class structure select for those scientists, often already insulated from those realities, who are able to model epidemics by Platonic abstraction. Perhaps that's an oversimplification on my part, but I bet you three years of funding that Lysenko would recognize his American counterparts.
pathogen rex: I'm not sure if you had a chance to look at the paper and the supporting material as I think some of it addresses your concerns (it is agent based modeling, not the usual dynamical systems models, although within categories homogeneous mixing is assumed, which is reasonable; for example, within a household or a classroom). I won't address the scientism issues as I don't think it's relevant here. The kind of modeling done here is qualitatively the same as the scenario spinning that people are doing. I would not call it scientism but Enlightenment thinking: a rational and evidence based approach. These come in all flavors of rigor and completeness but don't differ in epistemology, which is where my comment was directed. I'm pretty familiar with modeling (see the antivirals modeling series accessible via the left sidebar) and therefore also familiar with the many assumptions that must be made. I think that this paper takes a measured view of robustness. Read it if you have a chance, or if you have read it, I'd be interested in exactly where you think the problem is.
Racter: The peds number came from Nick Zamiska's Wall Street Journal article (don't have a link because he sent it to me by email from wherever the hell he is these days; China I think). In HK they have 3 peds deaths, frightening but so far not out of line with what be expected, which was the main point. One of the nice things about the PNAS modeling paper is that they explicitly include "Liberal Leave Policy" as one of the important interventions.
Revere-I again say that the plan is for complete and total shutdown and anyone who thinks different is wrong. Non-essentials will be shut out and only those who have to go will be allowed to. The change to this would come when it wouldnt make any difference, e.g. when more than 1/2 of the population got it or wasnt going to come out of it.
Lots of scenarios, but here is the first one. Transportation...turned off! Second food supplies.....One quick shot and then you guys are on your own. Third.....electrical supplies at the 3-5 week mark go down. One major circuit tumble in the Mid-West and/or the N'east if its winter and then its over.
They can model all they want and I did read it. Its one scenario and it puts a lot of faith into a lot of people doing the right thing. 5%? Yeah, you and they could be right. You run that past that magic 8% number and you are going to see people governing over the chaos that you suggested before. I also mean absolute anarchy in the mix and "defend what you got" which is a military saying might come into play. Our little neighborhood bird flu watchgroup has gone into some scenario playing including infiltration and invasions now. Oh we could get bowled over but only after there had been some major casualties...all theirs.
The report simply doesnt in my opinion cover enough. It certainly doesnt reflect anything past a 5% event.
I'll put it better... Would you bet your life or that of your grandbaby on it? I wouldnt let a thing happen to you or him Revere if it was within my power. He could eat my rations and I would gladly give it up for a kid. But its about time that both the state and federal government just stand up and said that if they are wrong about the CFR's for starts that 1/2 of this nation would be gone from all causes fire, food, freezing, flu. Everywhere we turn around now we got blizzards, floods, hurricanes, quakes..... and 9/11's. Any preparations that are made only are going to increase the outcomes.
Revere, first and foremost, as far as these types of models go, the three here are well turned. Multiple combinations of intervention tracked, spatial structure (although not discussed an iota), lots of data, computing power to die for, and a thorough sensitivity analysis. Fine mammas, the three. The execution isn't the problem.
It's instead the deficient epistemological proprioception. When we watch our three skinny models strut their stuff down the catwalk, cheeks sucked in, we realize their obviousness is rivaled only by their obliviousness.
The models fall flat not by virtue of sins of commission, that is, by imputing causality from a biased perspective, but by sins of omission, by a refusal to include important sources of causality clearly part of our objective reality. As alluded to in my previous post, social inputs are largely restricted to mathematical abstractions about as devoid of social content as we can imagine: population density, household size, workplace size, and commuter flow. Not that these don't matter, but the sociogeographic roots of epidemic emergence and spread are forsaken. Nothing on income, race and segregation, neighborhood health and safety, housing stock, rent load, local political histories, domain shifts in public health response, dislocation from urban renewal, community information flow, the topology of social networks, differential access to medical care, ecological resilience, etc.
People (and the viruses they carry) are treated as but billiard balls vectoring off each other along the homogenous social felt. Epidemiology becomes nothing more than tracking the mass action of social molecules. Interventions are limited to individualized treatment and social distancing. Never mind the policies that created the Rust Belt. Never mind the apartheid-like conditions in the cities. Never mind their effects on the sociogeography of disease.
Geographer Peter Gould tore such modeling a new one,
"The journals are flooded with one variation on the basic theme after another, all of them equally pretentious and unilluminating. We even have the ridiculous sight of anthropologists wandering around East Africa with their differential equations hoping to estimate transmission coefficients between sub-groups in the midst of a region where whole villages are being abandoned, hoping to "calibrate" their still purely temporal equations. The epitome, the ultimate folly of this approach came in a paper modeling the diffusion of HIV in the whole of New York City with 34 differential equations, churning out numbers down the time horizon. Geographically, of course, New York was homogenized and compressed to the head of a pin, simply because there was no need to consider any difference between the burnt-out Bronx and the trim lawn suburbs, or people in the packed tenement houses of a Harlem slum and the residents of apartments overlooking Central Park. After all, people are people, and since we are only playing computer games anyway, we can lump them together."
"As can be imagined, the conclusions were carefully couched in the language of "scenarios," but nothing could really cover up their devastating banality."
In this case, we have no difference between South Side and Gold Coast.
The distinction between SIR and agent-based is irrelevant. You missed the point entirely and, funny, that's something else I got out of AnnieRN's comment. The best trained researchers are often unable to see what directly confronts them. The myopia arises from a combination of cultural happenstance and an intellectual tradition tied to the service of empire. The White House Homeland Security Council, hell, any mayor's office, would not approve including measures of the social abandonment that has defined bipartisan national policy over three decades. With millions in funding at stake, and the pedigrees required for Washington access, university training and corruption are a fine line.
Tragedy and farce, back and forth, I can't decide. The three-prong attack is laughable. Let's see, let's get three groups to run something near the same simulation with the same variables and initial conditions. Behold! The models converge on something of the same results. Does the administration need to be told something three times before it sticks? That kind of effort I can respect, but pretending that under the three "different" models the effects of the interventions "are similarly, although not identically, effective in all three" is anything less than a con, well, I congratulate the good doctors on a good show.
I love too the obligatory "caution against overinterpretaton" and "the need for further field research." Much modeling means never having to say you're sorry. Roy Anderson's dismal models from the 80s predicting declines in HIV in Africa never cut into his Wellcome trust fund. Wrong? Just make another model and the funding wheel turns.
Now, it's not that we learn nothing from the paper. I did. Nor do I doubt the authors' qualifications and good intentions. But lofty allusions to the Enlightenment do not cover bad choices. AnnieRN nailed it--garbage in, garbage out. You tried to bully her by evoking scientific authority. And when called on that, even then you couldn't help yourself. Pronouncing scientism irrelevant doesn't make it so.
pathogen: I don't think you and I are going to converge on this one. George Box said, "All models are wrong. Some models are useful." I am arguing that there are elements of usefulness in this paper. I am not sure what position you are taking. You list many factors that may be relevant to how this all turns out. Fine. Go ahead. Tell me how you are going to take them into account. I'm all for immanent critique. I'll even go for ideological critique here. Give me the full Habermas if you want. I'd enjoy it and probably learn something. But what I'm getting instead is handwaving. What exactly is your analysis of how a pandemic would play out, given the current social structure and power relationships? What does it mean, exactly? As for your accusation I was bullying AnnieRN, I intended to do no such thing and if you read my comment I hope you will agree I did not invoke my scientific authority against her or those of the modelers. On the contrary, I claimed (and you are free to disagree of course) that I thought her epistemological view was not different than theirs and I said why I thought so.
I don't know why you say the three pronged attack is laughable. Since you understand modeling you know that these models were implemented quite differently (refer to the Supplementary material for more details) and it could easily have turned out that they produced very different kinds of results. It was an open question whether they would, although you seem to think it was self evident that this would happen. I can tell you it often, maybe usually, does not.
Lots of people don't like modeling. I think it has the potential to be useful, just the way qualitative research does (I just supervised a dissertation that used nothing but qualitative research methods -- not a p-value in sight) and just as critical theory does. I am not someone who thinks there is only one way to find out how the world works. But as someone who is also involved in public health decisions, I have to make them on the basis of whatever information I have available at the time, making the best inferences I can. Should we close the schools? It is a real question, not a theoretical one. Should we invest in antivirals, for everyone? targeted? What about work places? Real questions that might have to be acted upon. I'd prefer to have the benefit of some systematic thinking about this ahead of time. If you want to refine the analysis and ask questions about how risks and benefits are distributed, that's also appropriate. Do it. This paper is a data point, it's not the complete data set.
Questioning and skepticism of authority are appropriate and sometimes necessary. I got some broken bones and got arrested because I agree with you about that. It was a matter of conscience. I am not a slave to science. But there is also a form of unhelpful, unbridled and inappropriate skepticism that merely paralyzes and doesn't empower. I don't know if that is where you are or not as you haven't presented me with an analysis, only a complaint.
Look, revere, you're all over the place. You asked me what problems I had with the modeling. I told you. Now you say I failed to provide the analysis that will save the world from a pandemic. Not what you originally requested. A contract on par with that of the consortium and maybe I can schedule one.
You, the anonymous curmudgeon, accuse me of "inappropriate" skepticism, that I'm paralyzing, unhelpful, disempowering, a complainer, blah, blah, blah. Didn't I provide a list of social variables from work already out there, taking disease modeling beyond the physics envy of the PNAS paper? I'd think that be of some use in intervening.
Yes, dear, I read the supplementary materials. Yes, there were some differences, but the very aim of the exercise was to repeat something of the same simulation. The work isn't bad, not at all, I just think we deserve better.
it shouldn't be difficult to test the model
for seasonal flu :
one small city just do it during one season !
Isn't it worth it ?
pathogen: Whoa. Please read my comments carefully. This is an evolving conversation. If you prefer, call it a dialectic. That's part of the point here. Notice I did not accuse you of an inappropriate skepticism. I said skepticism can sometimes be inappropriate but I didn't know if that was the case here because I didn't know if it was just skepticism or backed by an analysis. So far it is just a complaint about models. I think I treated both your comment and AnnieRN's comment with respect by taking them seriously. Now you seem to be unhappy that I took you too seriously.
You did not really tell me what problems you had with the modeling, either. You alluded to things that were not incorporated in the model (that's the nature of models; they don't include everything) but not why they could not be included (BTW, the topology of the networks is included because of the kinds of datasets used) or what kind of analysis would be satisfactory. I didn't mean to ask you for a completed analysis, just an indication of what kind of analysis one might use. Perhaps I wasn't clear enough about that, so now I am clarifying.
You aren't required to respond. I won't think the less of you if you have other priorities or are tired of this. I am merely inviting you to respond if you care to.
anon: You're going to close all the schools and advise quarantine for households with a flu case in one city for seasonal flu to test a model?
Revere,thanks for the response. I guess I should have clarified. My concerns aren't at all with the models; any attempt to draw appropriate pictures of "what might happen" is an excellent idea, and frequently results in good end-use practice. My issue is that unless something happens which could make any of the various "better than worst-case" models possible, the actual result is going to be a default to a worst-case model--thus making the model-making process nothing more than an exercise of "tilting at windmills."
As long as the government isn't sending every American home a booklet giving the specifics on how to wash our hands, cough into our shoulders, stay home from work when we even start to get the sniffles, and store food for even two weeks, then nothing is really being done to get us off that lowest level. Real life is that hospital nurses are written up if they don't show up for work, even when they are really sick. Real life is the two little kids sitting in the grocery cart at the Wal-Mart pharmacy yesterday, both sick with upper respiratory illnesses. They were coughing and hacking in my direction only 2 feet from me, while waiting for their mom to pick up their meds. (Pity the unsuspecting person who gets that cart next, then inadvertently rubs his eyes.) I want to see public television programs with people giving real lessons on hand-washing, and telling me why, and how to store water. I want to see the head of the CDC doing 60-second TV ads encouraging medical systems to set up "flu only" entrances and departments in medical offices. Unless there are mechanisms to prevent sick people from waiting in pharmacies, or having to go into public--sick--solely to obtain medical care, it all falls apart, and the default happens. How is a person going to obtain Tamiflu, if he doesn't go to his physician's office--and wait with other people in the lobby before seeing the doctor--then go to the local pharmacy? And that doesn't even deal with the fact that to John Q. Public, "hand-washing" consists of getting the tips of the fingers wet after using the toilet, then touching the doorknob to leave the public restroom. I've worked in public health, hospital nursing, and teaching medical students. If faculty can't get medical students to wash their hands appropriately, how can we expect the public to do it?
The models are great, and they are extremely useful in guiding public health officials in appropriate directions for preparations for a pandemic, but they have to be transferred out of the lab at some point. I want something in the hands of the American people--NOW--to make anything less than the "worst-case" scenario possible. Otherwise, there is no point to any of it. While the experts are making good models, H5N1 is newly infecting more nations.
This reminds me of General George MacLellan during the Civil War. President Lincoln finally fired him for his refusal to take his relentlessly-trained soldiers into battle. We need to get out of the model-making, and onto the public health front lines of having prep conversations with the public. Yes, the models are specific, and useful. We can make models until the cows come home, but that isn't where true pandemic prevention is going to happen. True pandemic preparation is going to happen with frequent, specific, easy lessons in family hygiene and storage of basic necessities, taught to the entire U.S. population at once, over a period of time--and with the words "pandemic preparation" stated in each lesson. I want to see the frequent discussion of pandemic risk off of this and similar forums, and on the "Today" show. AnnieRN
Annie: One value of the comments thread is that it gives all parties an opportunity to clarify and think through what they are saying (I am mainly talking about myself, but it is also true for others, as you make clear). So here's my reaction/not disagreement about what you say. One value of models like this is to provide the kind of "hard" data (apologies to pathogen rex who will surely object to this characterization, although I mean it somewhat ironically) that decision makers seem to want and need. These models say that planning to handle a pandemic is not hopeless. That may or may not be true but it gives them some reasons to work on it, reasons they need given the absurdly large demands made on the absurdly small resources being devoted to public health. They have life or death choices to make, even in the realm of public education. That is why I have always favored solutions that work across multiple public health goals, including pandemics. And that is what we concentrate on here. Other flu sites focus more on individual prepping and protection, while we are interested more in the community level, not because one is more important, but for matters of focus, interest and choice.
But the models aren't just models, isolated from context. They have an effect on people and decision makers, which is why we talk about them here.
Would vaccination now for the current version of the avian flu have any protective effect?
I understand that the virus will have to evolve considerably before it becomes the nightmare beast of the worse-case-scenario. But even if a vaccine made this year protected only 5-10% of recipients, including the most recent version in our yearly vaccines might end up protecting an "epidemiologically significant" proportion of the population if done over the next few years.
Revere is right about modeling, its the same as table top exercises. They prove useful to people who might have to deal with the problems. I dont like what I am seeing at all by any exercises, modeling or the suggestion that beefing up the healthcare system if its past 8% CFR would really do any good. Its a complete and total FUBAR and I can only see a full blown Katrina only by 50 states if it happens. The folks in Hawaii, PR and the possessions all will be suffering and hard within a month and longer than the rest of us.
If it comes, to me its like going down to the beach to watch the tsunami. Its either an acknowledgment of whats going to happen, or heading down so that in your last few seconds on the earth you get to see the show.
Divalent: There are some data to say there is some cross protection, based on the development of antibodies protective in the test tube. What that means practically is hard to say, but there is quite a bit of talk about using a "pre pandemic vaccine" on that basis.
You're shameless, revere. In directly responding to my post you drop reference to an unhelpful, disempowering, paralyzing "inappropriate" skepticism. You don't need a degree in rhetoric to see what you aimed for there. When you're called on it, you declare in a disingenuous way that you never claimed I was these things. And that, "whoa," pathogen, you're clearly overreacting. Are you sure you don't work for the Hillary campaign?
In these dialectics, an analysis the reveres disagree with becomes a "complaint." Under their evolving rules of debate, analysis now requires alternatives, even as their posts have time and again skewered other researchers' papers without bothering with a surrogate. Of course, there is too the inconvenience that I did discuss other ways of approaching modeling albeit without the detail needed to operationalize the analysis. Declaring I didn't doesn't make it so. As for the details how a pandemic could play out in this U.S.A, rather than the one constructed in the PNAS paper, there is a journal article in press--not mine--that I'll forward as soon as it hits the stands.
BTW, the topology of the network is not addressed in the PNAS paper in anything other than a superficial way. The paper offers nothing about the dynamic nature and social origins of the connections and how they relate to a neighborhood's ability to respond in crisis. Mathematical epidemiology--an important field, I agree--need not mean modeling community health as if people were billiard balls.
pathogen: OK. Let's not belabor this further. We agree to disagree. I meant no offense. I like to argue. Since I am a mathematical epidemiologist and I don't think of people as billiard balls and don't treat them that way in my work I am perhaps slightly sensitive to how you phrased things. That is surely done with large systems of ordinary differential equations (but not the papers here), so I didn't address that although I discussed it in the modeling series (seventeen posts; see sidebar category mathematical models of antivirals). My remark about network topology referred to the combination of contact relations and spatial modeling which produces something essentially equivalent to a weighted network graph, with additional constraints. But that's a minor technical quibble between us. If you'd like the last word, I am happy to oblige. Meanwhile, I hope you keep reading and if something bothers you feel free to jump in with both feet.
Have enjoyed reading your comments AnnieRN.
Would have been nice for you to have been able to approach the mom with the two little kids too. However, people are so over reactive these days that I've discovered no matter how nicely it's stated people still become defensive.
Here is the leftist approach to reading it.
http://www.npr.org/templates/story/story.php?storyId=88239842&ft=1&f=5
It pretty much bears out what I said.... It gets loose in the US and it will result in total anarchy and chaos. AS NOTED previously, its a states problem if it gets loose domestically. For my way of thinking and understanding, they are pretty much tossing the towel in and going for infrastructure management. Not much they can do even if there were resources to do it.
Annie-Those things you want done are great but by order of the Congress, its a states problem. Pick up the phone and get your local EMA director on the tube. Bout all you can do. If the Feds get involved in the nuts and bolts operations, then they will be responsible for the whole thing. States rights issues came into play and the state governments weighed in and it was truly a Katrina response.
WE DONT WANT THE FEDERAL GOVERNMENT HANDLING OUR FLU PROBLEM!
That law passed without so much as a whimper. Everyone took a look at it and figured out that like Katrina, party affiliations might come into play. Such as "assessing" for three days as Blanco did and trying to lay the blame at Bush's feet for the Katrina response. She wanted him to put federal troops under her control... that was the sticking point. "Send us everything you've got", doesnt constitute a legal request.
So here we are and the silly population of the US is running around thinking that Unkle Sugar is going to be out passing 300 billion around like its candy. They might afterwards, but the money will be worthless. They also think that Unkle is going to feed, clothe and house them during it. Good luck. Devil generally takes the dumb and the poor.
I agree, Revere. Thanks! :) AnnieRN