We continue our summary of the Institute of Medicine "Letter Report" on non-drug non-vaccine measures to slow or contain the spread of an influenza pandemic of a severity similar or worse than that of 1918 (see previous post on models here). The IOM report examined several analyses of historical data from 1918 to see if it was possible to obtain information on the effectiveness interventions on the pattern of outbreaks in various cities in the US. It is well known that both timing and severity varied a great deal in that pandemic. The goal was to see if differences in morbidity and mortality were related to specific actions taken in response.
The IOM/NAS panel heard from Dr. Howard Markel, Director for The Center for the History of Medicine at the University of Michigan. He and his colleagues have identified 16 non-pharmacetutical interventions (NPIs), including such things as closing schools, restricting public events and making influenza a reportable condition. The overall conclusion from studying 6 cities in 1918 is worth highlighting because it echoes what we have been saying here for two years (can you think of a better reason?):
From these case studies, Markel concluded that investment in public health infrastructure and the building of public trust by local health officials seemed to have facilitated the implementation of the interventions. (p. 15)
There was also this important qualification. The community had to be committed to carrying out the intervention for the entire length of the epidemic (none did) and that even then, from his data, there was no guarantee:
He also observed that "fatigue" was an important factor; in other words, communities which had to reinstitute interventions after having lifted them experienced pushback and noncompliance in the second phase of restrictions. Finally, he concluded that the community interventions may have lowered the peak death rate and that proactive and early implementation were associated with flatter epidemic curves, although there were examples of cities that implemented the strategies but still had severe epidemics.
Dr. Marc Lipsitch, a well respected flu modeler from the Harvard School of Public Health, presented his analysis of 17 cities to see if he and his colleagues could discern whether early intervention affected the pattern or outcome of the epidemic. Using newspaper and secondary sources, Lipsitch et al. studied 17 NPIs to see if timing of intervention made a difference. Early interventions were considered to be those started when as yet few people had died in the city. The panel noted that using mortality as a measure of effectiveness is complicated by the fact that case fatality exhibited almost a three fold difference in across different cities. The general conclusions were that early interventions were related to lower death rate peaks but less of a relation with total deaths. Early school closures were most related followed by cancellation of public events. No other interventions were associated with the pattern of the outbreak.
One feature of analyses, both historical and modeling, is that they often come up with different results, illustrated by unpublished data presented by another modeler, Dr. Neil Ferguson of Imperial College London. Again, the method was to take advantage of the differences in timing and nature of interventions in different cities with very different epidemic patterns. First, there was some concordance with Lipsitch's results:
Lower peak mortality was correlated with "early" interventions--the same results that Lipsitch and colleagues (2006) found in their analysis. However, they also found that in terventions across the country were started within a few days of each other. The date when the epidemic reached the cities varied more. They also found that peak mortality was strongly correlated with the presence of two autumn peaks, but that total mortality was only weakly associated. These findings point to a major theoretical reason to explain why NPIs may have little impact on total mortality; that is, unless interventions are kept in place until there is no longer a threat of reintroduction, the interventions may delay when people get infected without having much impact on the total size of the epidemic (the total number of people infected). (p. 17, cite omitted)
Ferguson et al. also used historical data in a simple compartmental model to see if they could reproduce the epidemic curves (the development of cases over time), looking to see what intervention measures enabled them to do so best. It appears quite a few assumptions were needed regarding transmission and the effects of various interventions and these weren't sufficient to get a good fit unless another variable to account for spontaneous changes of behavior (e.g., voluntarily restricting contact with others) was added. These behavior changes clearly do occur independently of mandated interventions and in Ferguson's model their existence was required to get a decent model fit.
Ferguson et al. have interpreted their results to say that even simple models can reproduce the epidemic curves in cities with widely disparate experiences and that the best of these suggest a 40-45% transmission reduction. Early interventions that last the full duration of the epidemic are most effective but because they did not present data that separated the different interventions (e.g., school closures and mandatory masks), there is not as much information for policy makers as there might be.
Ferguson et al. presented a second set of analyses from French data from the 1980s which seemed to indicate that school closures made little difference, although this model is highly sensitive to assumptions about contact rates. Using the assumptions of the models, reductions in transmission from school closures were mainly in children, that is, the idea that infections in children drive the community rate didn't seem to be true.
The panel tried to summarize the disparate findings from the modeling exercises (which we report here) and the historical analyses, and their rather circumspect conclusions in the face of the many analyses deserve quoting:
The models generally suggest that a combination of targeted antivirals and NPIs can de lay and flatten the epidemic peak, but the evidence is less convincing that they can reduce the overall size of the epidemic. Delay of the epidemic peak is critically important be cause it allows additional time for vaccine development and antiviral production. Lower ing the peak of the epidemic is crucial also because it can reduce the burden on healthcare infrastructure by avoiding an extremely large influx of patients. Another important find ing is that interventions will likely be most effective if they are initiated early in the epi demic and sustained until the threat of reintroduction of the virus has been eliminated. (p. 19)
The panel also notes that the historical data are limited because there are many differences between 1918 and 2006, among them much higher population densities today. But again, there overall conclusion is worth repeating (we can't say it too many times):
[T]he committee believes that the finding from Markel and Wantz (2006) regarding the importance of a strong public health infrastructure in mitigating the epidemic likely remains true today. (p. 19)
Once again. The importance of a strong public health infrastructure.
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It seems to me a no-brainer that schools would be a major factor in promoting transmission. You group 300 - 3,000 individuals daily (many with appalling personal hygiene) in a crowded, often poorly-cleaned building in which they regroup repeatedly through the day in crowded classrooms, hallways, locker rooms and cafeterias, and then all split up and go home at night to intimate contact with families and family members who themselves spread out far and wide the next day. It's got to be a virus' dream come true!
Of course, having them all assemble at the mall instead isn't going to offer much of an improvement...
What about the account of how families went out and helped their neighbors; one (was this the man from NZ?) said he was bringing their wood and lighting their fires and fetching their water for them because they were too weak to do it themselves, and, finding people black and dead it their beds - he was 8 and finally couldn't take going around anymore; he lived to tell the tale, but, how many others circulated and helped until they got sick? "Closing school" didn't mean all the kids stayed home and avoid contacts I'd suppose.
"unless interventions are kept in place until there is no longer a threat of reintroduction" I'm all for that
and I think the public would be too
if they understood the scope of what they'd be up against.
My kids carry full face plate masks in their backpacks. Wipe the face with sanitary wipes and don the mask is my order if ANYONE turns up with it and to take that unapproved cell phone out and I will come get them, brining a portable decon unit so I can put them into the car.
As parents we will have to pull them on our own because the acknowledgment that its here would just overwhelm the teachers and school system administration. It would only be a week or so before they did it anyway. You will just have to take the heat for doing it and "unexcused absence" will be replaced by "smarter than we are". They cant get it if they dont place themselves into an unsafe proximity. Its not as a rule wind driven (Oklahoma is excepted-the wind alway blows there and California in a Santa Ana) except in crap and dust so we can have some leeway but not about proximity. Bathrooms and toilets in particular are HUGE vectors from fecal atomization, so keep the seats down too!.
I can see from the post that there is a lot of speculation. I can only say that if you treat it like its a bioweapon gone off then your chances at survival go up tremendously and that means hard core treatment of the situation. If its a mild pandemic you just hold on and ride the pale horse having knocked the pale rider off his mount.
Stepping aside from whether taking kids out of school would actually help or not,
Were schools to be closed, what effect would this have? In the majority of households here, both parents work. Children cannot be left at home unsupervised. Many children would not have siblings of school age old enough to supervise them. Therefore, one parent must cease working to care for the children while schools are closed.
Therefore a sizable proportion of the workforce stops showing up at work (I don't think one can assume that retired family members eg grandparents would be able to care for children - a lot of people in this country don't have relatives living anywhere nearby)
This may have an impact on service delivery.
It seems it would be desirable to make this explicitly included in preparedness plans.
We have a reasonably thorough plan for avian influenza in Australia (although the question of where the staff to carry it out would come from remains unaddressed) - I only hope that the human medicos get off their backsides and sort out a human pandemic influenza one.
A recent outbreak of seasonal influenza in a nursing home for the elderly in Canberra took more than a week to be diagnosed as influenza (as opposed other kinds of pneumonia) and have an influenza plan activated - if this were a pandemic strain, that would not have been fast enough to prevent disaster.
attack: This is part of the conundrum. Some of the differences in the models relates to assumptions about how much contact with be caused by taking kids out of school but putting them somewhere else (e.g., ad hoc play group or the mall).
Revere do you really think parents are going to be forming play groups or allowing their children to hang out at the mall during a pandemic? I dont. Give the public some credit. Im far more comfortable with the judgment of the general public than I am with the government who seems to have as a top priority saving the economy rather than saving lives.
The unwashed masses are not as dumb nor as prone to panic as the government seems to think. I trust my fellow citizens to at least show a little common sense. Providing they are not lied to oops I mean managed by TPTB. Given the truth, the public will respond much better than those governing them
Click on my user name to see a wikified review; it will take you to "case for early school closure" which includes "benefits" and "secondary problems".
We're still working on it, and your help is needed; no easy task. At the top of that page there are links to the forum threads (and to a reworked version of the wikipage). Thanks!
I think much of our response will be based on its virulence. We would all be more prone to isolate ourselves at a 50 percent survival rate, while with 95 percent, hey, who knows?
My youngest son was quarantened with mumps last spring (who knows where he got it,he had all his shots!) We were snuck in the back door of the hospital for diagnosis, when I asked about the paperwork I was rushed out the door - "later!" they cried. His siblings were required to wear facemasks around him, and he was asked to stay home for a week. Well, I can tell you since he wasn't even remotely sick aside from a small swelling on his jaw line, the facemasks went by the board in about a day after the novelty wore off. Staying home, even with full services for that week was difficult in the sense that we were bored silly. Not that we didn't have enough projects, but most of the boredom was in knowing that other people were out in the world going to school and having birthday parties, and participating in soccer tournaments. It takes a tremendous amount of will to self-isolate.
janetn: Yes, I am sure some parents will form play groups or the kids will go to the mall (if it is open). Many will have no choice but to get together with other parents because they will have to go to work and can't leave the children. The modelers are aware of this and included caveats about it.
Right, the kids stay home, with teenage Buffy taking care of preteen Biff, whilst Mom and Dad go to their offices in the financial district daily, thereby picking up more germs than kids at school. And then the parents come home and share it with the kids.
Has anyone bothered to ask what good it does to have people trading in derivatives or working checkout counters at trendy shops in the malls while tens of thousands of people are turning blue and dropping dead in the streets...?
"Oh, but we have to keep the economy going."
No we don't, the economy has to keep us going.
The solution for this one, really, is to just shut down the economy for the duration, with the exception of essentials. That also means shutting off the relentless ticking of the clock of accrued interest, mortgages and rents, and so on. Take a big hit by design, or take a bigger hit by "doing nothing."
Either the tool serves the person, or the person serves the tool. Take your choice.
(Don't let tptb choose g510; look at their track record so far!)
"The solution for this one, really, is to just shut down the economy for the duration, with the exception of essentials.
That also means shutting off the relentless ticking of the clock of accrued interest, mortgages and rents, and so on.
Take a big hit by design, or take a bigger hit by "doing nothing."
-Makes sense to me, which may mean it is ''not'' what tptb will make happen.
They seem to be willing to risk a depopulating event.
(Darn them all to sit deathwatches and be the Mortuary Reserve Corps for saying,
The public -or tptb's stock options?- can't handle the truth, but, we'll let the public and their children handle the consequences.)
:-/
The human factor in tptb will be the behaviour and it will be based on the information they received and processed in the time before it bursts out.
The reactions I gathered from the parents of children at the school of my own child about a common flu vaccination this season had the message that it didn't bother them. These people are working as nurses and medical workers in health care, home care and the like. One nurse told me she was one of the few who showed up for a vaccination shot. They won't get their annual cake this year because they didn't even approach the numbers needed for this vaccination reinforcement.
As long as people don't know anything about tptb they will have the common sense reactions like: 'my immune system never let me down'. They are convinced a disaster like this can't happen because it's too terrible. They will be taken care of by the government.
No, they won't.
They will need to save some fuel in the house to drive to Big Pharma to line up for an essential shot, have solar energy to receive the message when it finally wil come by local radio and take their syringues with them to get the untested liquid and hope for the best.
Yes, both parents work in most families, but many kids are old enough to stay home; older sibs can babysit the younger ones, many parents can telecommute or work flex hours, and others can go to neighbours, relatives, and/or smaller daycare play groups. We figure it out whenever there's a teachers' strike.
It wouldn't be perfect but if we're talking about slowing transmission, buying time, flattening out the top of the curve where everyone's getting sick at once, easing the pressure on hospitals, having fewer parents infected by their kids so they do still have the option of going to work to maintain critical services, etc... (not to mention perhaps saving our kids)
It's all incremental, but I don't see any magic bullets that make more sense.
Not to mention that with a flattened transmission rate the secondary effects like supply chain collapse, diabetics without insulin, etc. will be ameliorated.