Where's the science that determines how strict a lockdown we need?

The Quarantine Zone
81

The problem is that antigen testing (for the presence of active virus in an infectious patient) has often been a very incomplete or biased sampling—in California, for instance, until early April it was impossible to get a test unless you were presenting profound signs and symptoms, and sometimes not even then—and a lack of antibody testing means we don’t really have any good idea of how many people were essentially asymptomatic, with ‘official’ estimates ranging from 20% all the way up to >80% of asymptomatic carriers. We also don’t know for how many days presymptomatic carriers can be infectious prior to presenting symptoms, and how long after symptoms subside that they stop being infectious. We don’t know how long asymptomatic carriers can be infectious or just how much virus they may shed. We do have some pretty clear signs that the virus may be aerosolized to a degree even in asymptomatic or presymptomatic patients due to the large amount of community transmission but just how much that occurs versus droplet and fomite transmission is not well characterized. There is also the large discrepancy in severe morbidity and mortality between pale skinned people and those with darker skin (not just blacks but Hispanics, Indians, et cetera) and the factor of three difference between mortality in women and men. And even the number of reported deaths is not reliable; we know with a statistical degree of certainty that China underreported their deaths, that deaths in Spain and Italy are still underreported, and even in the US and Europe there is likely a significant amount of underreporting due to attributing COVID-19 deaths to other underlying conditions and lacking the ability to confirm presence of the pathogen. Even the most reliable testing data we have (from South Korea, Iceland, Luxembourg, New Zealand) are giving inconsistent measures of reproduction number and case fatality rates, and of course in the United States the large number of false negatives (reported to be in excess of 30%) makes testing barely more reliable than flipping a coin. So the data is…garbage, at least in terms of making any good predictions of future trends, hence why every leading epidemiologist is calling for widespread antibody testing.

As for applying knowledge from previous epidemics, the behavior of this virus is so out of family with influenza, measles, chickenpox, et cetera in terms of the combination of infectiousness, the latency and number of effectively asymptomatic carriers (albeit of unknown infectiousness) that this pandemic is essentially unique in living memory. The best comparison might be the poliovirus or rubella, but it has been half a century since the developed world experienced these diseases at epidemic levels which was back before air travel was common, and the general methodology of the time was to either shut down (as we are doing now) or let the contagion burn through the population until herd immunity levels were achieved because there were few other practical measures to track and trace large scale epidemics. Given that we still don’t even understand basic epidemiological properties of the contagiousness of this virus, it is difficult to make quantitative comparisons to past epidemics, but frankly, we’ve never had the means to effectively deal with an epidemic this contagious before; most of our experience successfully fighting epidemics stems from either implementing existing vaccination programs (influenza, polio, MMR< chickenpox) to achieve herd immunity prior to exposure, or dealing with pathogens like Ebola and Marburg which, while causing horrifying diseases are not very contagious and are never asymptomatic so quarantining symptomatic patients and those who have been in intimate contact with them is highly effective at containing an outbreak.

Epidemiologists an build models, vary parameters, and looking at what different conditions and different types of measures may do compared to an assumed baseline is feasible, but with such poor quality and unreliable data, making accurate predictions that aren’t uselessly broad ranges is just not realistic.

Stranger

82

Originally a number of popular parks such as Zion, Grand Canyon, Klondike, and Yosemite remained open just for the reasons you state. Unfortunately, people did not adhere to social distancing guidelines, and park rangers (who were not provided with any protective equipment) balked or quit because of the threat of contagion. And of course, this encourages people to travel from their homes to often distant parks, even though that is exactly the opposite of what is needed to stop the spread of the virus.

As for “rapidly escalating fines…if someone with a ticket then gets sick, no ventilator for you!” that is neither a practical deterrent (since these people don’t seem concerned about contracting the virus) nor would any physician find it ethical to deny treatment to a patient just because they had a citation.

Non-respirator asks, by the way, [POST=22230904]are of questionable utility even in preventing you from spreading the virus to others[/POST] and thus should not be relied upon by themselves as an effective contamination protocol notwithstanding that the way most people are wearing and handling masks may actually increase their potential to contract and spread the virus. Wearing masks is one of those things that seems like a good idea in principle, and certainly if you are sneezing or coughing it will prevent ejecting droplets over long distances, but they will not stop exhausted aerosols which can remain suspended in air, so just wearing masks is not in and of itself sufficient. What is needed to stop the epidemic is physical distancing, isolation, and most of all, effective and reliable antibody testing.

Stranger

83

I was thinking about local parks and forest preserves, rather than destination national parks. Sure, enforcement officials ought to be provided sufficient gear for writing citations. The “no ventilator” comment was made - mostly - in jest. Tho I personally would support it, it would never be implemented.

I thought I had read several places that a well-constructed mask was very effective, and even a bandanna was largely effective. I appreciate your DIY efforts, but I’d hope for something a little more robust for the formation of public policy.

84

The CDC guidelines on closing schools have been rather ambivalent. In particular, they observe that “In other countries, those places who closed school (e.g., Hong Kong) have not had more success in reducing spread than those that did not (e.g., Singapore).” But ISTM that politicians have uniformly closed schools in the US.

Politicians are frequently motivated by the need to do something, and even more so, to be seen as doing something. But that’s politics, on this issue as on every other.

85

One difference between the approach to the “problem” of effective measures of limiting pandemic infection rates between scientists, and politicians is that politicians are influenced by factors scientists deliberately do not consider. What the population actually does with information is make decisions based on preferences. Politicians have to avoid suggestions which have a high rate of negative preference among their voter demographics. The accuracy of the suggestion is entirely irrelevant. The scientist prefers to eliminate the datum of political acceptability entirely from consideration. Viruses are not amenable to political argument. Human populations are highly resistant to unpalatable observations, especially when they are highly accurate.
Complete freedom includes the freedom to act the complete fool, and cause suffering to others as long as you can’t be legally proven to have done so with the intention to do harm.

86

The biggest problem I’ve seen is that there’s no way to handle the parking safely. People congregate in the parking areas, near cars, along roadways even if they disperse once inside the park. Many parks around here are open, but the parking lots are closed. If you can get there on foot you’re good to go.

87

I would agree with the general sentiment to keep parks and public spaces open with some kind of control over the number of people and encouragement to maintain physical distance because the benefits of fresh air and sunlight on both mental and physical health are manifest; there have been suggestions that the reason darker-skinned people are seeing worse presentations because they do not manufacture as much Vitamin D, and humans produce Vitamin D in response to sunlight (although you can and should consider supplements as well). However, the reality has been that opening up parks and beaches, or even public interactions in areas where they aren’t open, have resulted in people being extremely incautious. Last weekend four or five families literally had a street party in front of my place after getting food from the restaurant downstairs. There was zero effort in evidence of any kind of “social distancing”; kids were wrestling with one another, adults were mingling around in kissing distance, and someone eventually started passing a vaping pen around because…of course they did. So, while the reality is we could stop the epidemic in its tracks (at least, temporarily and enough to get a handle on critical cases overwhelming hospitals) we won’t because people collectively are selfish assholes who believe that the virus is someone else’s problem to deal with.

I don’t know where you read that but I have seen no objective evidence of it. On the other hand, while this is hardly a systematic trial, this would seem to reinforce my observations that woven cloth coverings are not particularly useful in preventing the spread of very small droplets and aerosols. They will prevent large droplets and sputum from being expelled over longer distances which may be of some marginal benefit, but once the mask becomes saturated you are essentially expelling or inhaling an aerosol of whatever is stuck to the mask, and of course anyone who adjusts or removes that mask without cleaning hands afterward is just transferring the material on the mask onto doorhandles or other surfaces.

Wearing woven cloth or surgical masks are still useful in signaling that you are taking distancing measures seriously and that you presumably expect others to do the same (although I see people walking up to one another and then pulling down their masks to speak and express, which pretty much negates any point of wearing the mask at all) but as a measure of actually limiting contagion it is of little efficacy, and thus, should not be relied upon as a means of letting people be in closer proximity for business or leisure.

This is exactly the problem; virologists and epidemiologists can recommend the most effective measures that the science determines, and politicians can listen (or not) to those recommendations, but ultimately without a Wuhan-style lockdown requiring the imposition of martial law, people will do what their conscience and their personal beliefs lead them to do, including attending large gatherings at religious services because they think their deity will protect them. And as a politician, you have to walk that line between what is objectively the right thing to do and what people will accept. Unfortunately, “the freedom to act the complete fool” isn’t just limited to those people and their immediate families, but to the continued spread of the SARS-CoV-2 virus whether they believe it or not, and taking a look at the current verified infection numbers (and qualified estimates of what actual infection rates are) we are looking to be in the same situation as Italy and Spain. But making absolute predictions isn’t really feasible due to the lack of good quality data, so all we can do is compare.

Stranger

88

Yeah, that’s what I heard, that they were going to close the pkng lots. Just seemed so weird to me - I use parks and forest preserves ALL OF THE TIME, and absolutely ZERO part of that use involves congregating in the parking lot… :confused:

In fact, I was biking through a FP w/ my sister this a.m. when she told me about this.

89

My impression is that it’s not a matter of people intentionally congregating in the parking lots - it’s more matter of people incidentally congregating as they get out of their cars and remove backpacks or whatever from the car , walk from the parking lot into the park and so on and in reverse when they leave.

90

If folks are getting frustrated by this all, it’s probably because they perceive people talking out of both sides of their mouths. On the one hand it’s ‘listen to the experts, you’ve got to listen to the experts, they’ve spent their entire professional lives on this and they know way, way more than you could ever hope to learn’. And on the other hand it’s ‘when it really comes down to it, we don’t know jack shit about this thing, and really how could anyone ever?’.

91

…there aren’t “two sides.”

The experts say that social distancing is the best tool in the box to protect ourselves from Covid-19. And to be able to open up again you need contact tracing, wide spread and constant testing, isolation of suspected infected people, we need to protect our healthcare workers.

We know this works. We can see it working in places that have implemented this and we see it failing in places that haven’t.

We also don’t know a lot about this specific coronavirus. The fact that we are learning more and more about this specific coronavirus is seperate from what we need to do in order to mitigate its effect.

So yes: the advice provided by experts will save lives. And the experts also don’t know everything, nor do they claim too know everything, and the fact that they don’t know everything isn’t a reason to ignore the things that they do know.

92

Putting it another way: the experts say we don’t know everything yet about this virus, so we’ll rely on the things that we do know to be effective in fighting it. That means social distancing, massive testing, and so forth. As we learn more, we’ll come up with better solutions. Until then, we’ll use the tools we have, that we do know work.

93

FiveThirtyEight.com released an interview with Dr. Chris Murray who developed the widely cited IHME COVID-19 model on the challenges in validating such a model with the widely varying data that has been available, as well as how people will misinterpret model projections or assume that model projections at a given time are an absolute prediction. It’s a long form interview at over 42 minutes but it is well worth listening to if you want to understand why we don’t have predictions with high confidence and how hard it is to account for the effectiveness of measures short of full isolation in preventing the spread of the virus.

Stranger

94

Too many unknown variables.

95

Here’s an article with scientists saying that 30,000 people would be dead by now in Illinois without the measures taken:

That sounds believable enough to me. We need more information out there like this (plus what we’re paying to get these results).

96

These guys may be right and they may be wrong, but the fact that they have a “model” which produced those results means little to nothing.

People put out all sorts of complicated models which are very rigorous in terms of the mathematical sophistication and the like, but the results can vary very widely based on the assumptions being fed into the model, which often don’t have a whole lot behind them (often due to the fact that it’s just difficult or impossible to come by solid assumptions). So it’s important to know the nature of and basis for the assumptions that the model used and not just look at the fact that there’s a highly sophisticated model being put out by some Very Smart Guys.

97

Yes, testing has been sparse in the US. But it hasn’t been sparse everywhere in the world. Some other countries like South Korea have done extensive tests, and not only can we use that data directly, but we can also use it to calibrate the results of testing in places where it’s sparse and selective.

98

Actually we really don’t even know that. Or least which components that have been used of that are effective and which accomplish nothing while causing harms. There are no controlled trials to rely on, and there are so many things that vary between nations, states, and regions, that it is difficult to even come up with decent associations.

There are small pediatric history vignettes to share here - there are toddlers with feet that turn in from the hip, called femoral anteversion, or from the lower legs, called tibial torsion, sometimes so bad that they trip over their own feet when they run. Back in the day '60s to '80s orthopedists would see those kids and put them all in these contraptions called Denis Browne bars which forced the feet to point outwards. And sure enough after a year or so in the bars kids toes started to point more straight ahead! It took years (until 1991 actually) until someone actually did the controlled trial that showed that kids turned straight ahead in the same time course without the bars too. (The bar still has an appropriate use for clubfoot treatment.) It is similar today with the helmets for flat backs of the head: yup those who are treated are rounder by age two … and so are those who are not. By two you can’t tell them apart (with rare severe case exceptions).

Thing is in the context of not having those trials clinicians needed to decide what to recommend: doing and not doing were both decisions. What to advise in the face of uncertainty, without the luxury of controlled trials, or even with controlled trials that are not yet quite enough to completely convince all?

Is that decision to act or to not act in the face of such uncertainty one of “science”? Should a burden of proof be on an “act” or a “not act” side of the scale? Should it be informed by a full analysis of the possible consequences of each choice? And an understanding of the magnitude of the uncertainties?

IMHO science is all about understanding the degree of our uncertainty and managing it. Unfortunately communicating uncertainty and possible cautions in its face is … difficult.

We don’t really know how strict of a lockdown we need. More importantly at this point is that we don’t know what we do NOT need. There is no real science to determine either. We know broadly that social distancing can slow spread of infectious diseases, but which elements contribute what for a new germ? Not known.

The process going forward is going to have to be real time experiments of reducing those elements that those best informed make their best educated guesses are the least impact on reducing spread for the most impact on improving economic health and quality of live, seeing how it impacts key parameters, and then moving on from there, informed by those results, watching the experiments that other countries and states with their results along the way. It won’t be controlled trials and it will be messy. What happens in Austria, or wherever, may or may not translate to Illinois or Florida. But these experiments and new data as it comes in and reduces the huge uncertainties of the models, are the closest possible to having science underpin the decisions as we are going to be able to get.

And we cannot assume the results of the experiments before they are run even if we have predictions based on models we hold dear, we just have to be prepared for the possible range of results, and open minded in how we interpret them, looking to have our held hypotheses falsified.

99

I couldn’t find this earlier but: Annals of Work Exposures and Health: “Simple Respiratory Protection—Evaluation of the Filtration Performance of Cloth Masks and Common Fabric Materials Against 20–1000 nm Size Particles”

Conclusion

  • Common fabric materials and cloth masks showed a wide variation in penetration values for polydisperse (40–90%) as well as monodisperse aerosol particles in the 20–1000 nm range (40–97%) at 5.5 cm s−1 face velocity. The penetration levels obtained for fabric materials against both polydisperse and monodisperse aerosols were much higher than the value for the control N95 respirator filter media but were in the range found for some surgical masks in previous studies. Penetrations of monodisperse aerosol particles slightly increased at 16.5 cm s−1 face velocity, while polydisperse aerosols showed no significant effect except one fabric mask with an increase. The penetration values obtained for common fabric materials indicate that only marginal respiratory protection can be expected for submicron particles taking into consideration face seal leakage.*

Stranger

100

Huh. I’d underline a different line:

“were in the range found for some surgical masks in previous studies.”

No they do not compare to N95 masks. Neither do surgical masks. But if the goal is to reproduce the efficacy of surgical masks, which are aimed more at reducing droplet transmission (5 microns or bigger I believe, not submicron)? I don’t think this cite informs.

OTOH it seems you are still correct! :slight_smile:

The authors’ update in times of COVID-19. Essentially a cloth mask may be better than nothing.