Tag Archives: Pandemic

Variolation May Cut Covid19 Deaths 3-30X

(Here I try to put my recent arguments together into an integrated essay, suitable for recommending to others.)

When facing a new pandemic, the biggest win is to end it fast, so that few ever suffer. This prize makes it well worth trying hard to trace, test, and isolate those near the first few cases. Alas, for Covid-19 and the world, this has mostly failed, though not yet everywhere.

The next biggest win is to find a cheap effective treatment, such as a vaccine. And while hope remains for an early win, this looks to be years away. To keep most from getting infected, at this point the West must apparently develop and long maintain unprecedented expansions in border controls, testing, tracing, and privacy invasions, and perhaps also non-home isolation of suspected cases. Alas, these ambitious plans must be implemented by the same governments that have so far failed us badly.

Yes, there remains hope here, which should be pursued. But we also need a Plan B; what if most will eventually be infected without a treatment? The usual answer is “flatten the curve,” via more social distance to lower infection rates, so that more can access limited medical resources. Such as ventilators, which cut deaths by <¼, since >¾ of patients on them die.

However, extreme “lockdowns”, which isolate most everyone at home, not only limit freedoms and strangle the economy, they also greatly increase death rates. This is because infections at home via close contacts tend to come with higher initial virus doses, in contrast to the smaller doses you might get from, say, a public door handle. As soon as your body notices an infection, it immediately tries to grow a response, while the virus tries to grow itself. From then on, it is a race to see which can grow biggest fastest. And the virus gets a big advantage in this race if its initial dose of infecting virus is larger.

This isn’t just a theory. The medical literature consistently finds strong relations, in both animals and humans, between initial virus dose and symptom severity, including death. The most directly relevant data is on SARS and measles, where natural differences in doses were associated with factors of 3 and 14 in death rates, and in smallpox, where in the 1700s low “variolation” doses given on purpose cut death rates by a factor of 10 to 30. For example, variolation saved George Washington’s troops at Valley Forge.

Early on, it can be worth paying such high costs to end a pandemic. But once a pandemic seems likely to eventually infect most everyone, it becomes less clear whether lockdowns are a net win. However, the dose effect that lockdowns exacerbate, by increasing dose size, also offers a huge opportunity to slash deaths, via voluntary infection with very low doses. Continue reading "Variolation May Cut Covid19 Deaths 3-30X" »

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Do You Feel Lucky, Punk?

A recent influential report posed the key Covid-19 issue today as: to mitigate or suppress? Should we focus on “flattening the curve” under the assumption that most everyone will get it soon, or adopt even stronger measures in an attempt to squash it, so most never get it.

Some simple obvious considerations are:

  1. if successful, squashing saves many more lives,
  2. you have to do a lot more to squash than to flatten,
  3. while flattening policies need be maintained only for a few months, squashing policies must be maintained until a strong treatment is available, probably years, and
  4. squashing is far easier when you have only a few infected and when your trading, travel, and physical neighbors don’t have many infected.

Several nations, mostly Asian, seem to have successfully squashed so far, though they started when they had few infected. China and perhaps S. Korea are the main examples of squashing more than a tiny number of infected, though even they had far fewer than we do now in the West where so many are suddenly eager to squash. China had much recent experience with mass surveillance, controlling population movements, and enforcing strict rules. Even so, they screwed up badly early on, and it isn’t at all obvious that China’s squashing will keep working as they let people go back to work, or when many big neighbors get highly infected.

The main point I want to make in this post is that trying to get your Western government to suppress Covid-19 in the usual way is making a big bet on the their quality, and the quality of typical neighboring governments. And also of your public’s commitment. As in the famous Dirty Harry (non-)quote, I ask: “Do you feel lucky, punk?”

Western government agencies and expert communities so far have had a bad record dealing with Covid-19. At first they criticized China’s strong measures and focused on signaling political correctness. The US government badly screwed up the generation and regulation of tests and masks, and the West continues to fail to cut regulation preventing rapid expansion of medical personnel and resources. Western governments only changed policies when public opinion changed, and even now seem more focused on handing out cash to allies, and symbolic but useless acts like banning bicycles.

As with most policy, you must expect that the details matter a lot. So even if you see China policy as a success, you shouldn’t have high hopes if your government merely copies a few surface features of China policy. That only works if this is a simple problem, with simple solutions, and few problems are that simple. This is not just a problem of insufficient moral fervor.

You should have higher hopes if they copied the whole China policy package relatively exactly, and even higher if the Chinese officials who managed their policy implementation personally came to manage implementation here. Even then climate, cultural, or infrastructure differences might mean their policies don’t work here. But no government seems even interested in copying the exact China package, and in my recent poll, 80% of 927 opposed this last idea of Chinese management.

Dear Western citizen, your government has already demonstrated incompetence at dealing with this in the absence of public pressure, and public pressure will mainly push them to do what they guess they would be most blamed by the public for not doing if things go badly. Regardless of whether that actually works; the public may never learn what actually works.

This pandemic has already been allowed to get much bigger than any that has ever been squashed before, and it is harder to squash than most, passing via the air, living on surfaces for days, and with infected folks showing no symptoms for a week. And in contrast to China, your government doesn’t have much recent experience with the mass surveillance, movement controls, and strict rule enforcement.

And yet now at this late date, you are considering if to authorize these same governments to oversee not just large efforts to flatten the curve, but the more extreme efforts required to squash it. Even knowing that to make it work you’ll need very strong public support in a far less-communal culture than those that have so far managed to squash.

Mind you, you are now considering this not because you have great confidence in your government’s competence, or your public’s support. But mostly, it seems, because it would look morally bad for you to give up hope on the millions who will die even if we flatten the curve well. Really, do you feel lucky, punk?

Also consider: even if your local government manages to successfully squash its internal infections temporarily, what happens if half of its neighbors fail, and become mostly infected? Or what if they succeed for a while, but half of their neighbors fail? What will it take to keep external infections from overwhelming you then? Or what will it take for your government and others to coordinate to ensure that most governments succeed? Remember, these are the governments who have so far largely failed to prevent massive illegal immigration, and who continue to fail to coordinate to limit global warming, war, and ocean overfishing, or to promote global innovation.

This wouldn’t matter much if the policies for squashing looked much like the policies to flatten, so we could actually flatten but pretend for a while that we were trying to squash. But there are policies that could help to flatten that look obviously bad for squashing, such as deliberate exposure, which might cut 3/4 of life-years lost. And locking down the economy and social contacts for many years at a level that looks at all like it might succeed in squashing is going to involve enormous costs to the economy and your freedoms.

In my recent polls, 73% and 74% of 393 and 533 respondents predicted US and world (respectively) will become >25% infected before an >80% effective treatment was given to >80% of world. So 3 in 4 agree that global containment just isn’t going to happen. Yet, to show that they care, most governments are giving lip service to squashing as their goal, not flattening. How far will we all go in paying huge costs to pretend that this is at all likely?

Before we all jump off this cliff together, can we at least collect and publish some honest estimates of our chances of success? Such as perhaps via conditional betting markets? If you aren’t willing to exactly copy the whole China policy, or have them manage it, how serious could you really be about succeess?

Look, this is like starting a war. Its not enough to ask “would it be nice to win such a war”, we need to ask “can we actually win?” Don’t start what you can’t finish.

I fear suppression is a monkey trap; afraid to let go the nut of saving everyone, we’ll be trapped in the gourd of not saving nearly as many as we could have.

Added 20Mar: Note that the many responses defending suppression talk about how many lives could be saved, and how they can imagine a plan that would work, but none address the issue of how competent is our government to implement such plans. Amazing how easily people slip from “it could be done” to “my government could do this”.

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Expose The Young

23Mar: Sorry for doing this, but I found errors, & can’t stand to let them stand, so I’ve edited this substantially to fix them. The more features one adds to a sim, the more chances for bugs!

In my previous analysis of (voluntary) deliberate exposure (plus immediate isolation), I assumed that people were quarantined and exposed at random. But there seem to be good arguments for preferring either the young & health or the old & sick early. Exposing the old early gives them access to a less overwhelmed medical system, while exposing the young early allows the population to more quickly reach “herd immunity”, saving the old from later exposure.

To see which effect is stronger, I’ve changed my spreadsheet model to let the population be split into two groups who can differ in their death rate, and in whether they are quarantined or deliberately exposed.

As before, I start with one random contagious person in a US-sized population of 327M uninfected. After 7 days each contagious person becomes visibly sick, 10% of these need an average of 7 ICU days of help, and after 7 days some fraction of sick folks die, while the rest recover and are immune. Sick folks are added onto the usual 10K people who need ICU help each day, and their death rate goes as the log of the daily total number of people who need ICU help. If only 10K people total need ICU help, only 0.4% of sick folks die, but if 50K per day people need ICU help, then 3% of them die. (See below for alt death rate function.)

The number of infected people who become contagious each day is proportional to the product of the uninfected count times the contagious count. Except that there is a quarantine that always holds 10M people, with a proportion of contagious vs. uninfected the same as the larger population from which it is drawn. People in quarantine have only 2% leakage of the usual rate of infecting others. (See below for alt leakage rate.) The infection rate parameter is set so that, early on, the death so far count doubles about every 6 days. 

To allow an old and a young group, I found US estimates on the population fraction and life-years remaining for different age and gender combinations, and also on how COVID19 death rates change by age, gender, and comorbidity.  From these I’ve defined 72 groups which vary in age, gender, and a binary health-or-not, and produced estimates for each group on life-years remaining and COVID19 death rate. Sorting these groups by death rate, I can split them many ways into two groups: “young” with a lower death rate and higher remaining life-years, and “old” with a higher death rate and lower life-years. Depending on the cutoff between young and old, the ratio of their death rates varies from 36 to 6781, and the ratio of life-years remaining varies from 1.7 to 10.4. 

I compared 8 options with varying combinations of who is quarantined: all (= random), young only, or old only, and also who is deliberately exposed: none, all (=random), old only, and young only. As before, I assumed a quarantine big enough to hold 10M, and that higher death rates induce higher needed ICU days. For each option I crudely searched to minimize the total lost life years by varying the young vs. old cutoff, the number of days of deliberate exposure (E days), and the fraction of the quarantine used for those deliberately exposed (D % of Q).

The following table shows my results, as do 3 graphs at the end of this post.

The 4th and 5th columns (% Deaths and % Adj. Deaths) give the percent of deaths, and life-year-adjusted deaths for each option relative to the first (baseline) option. Note that both choosing to deliberate exposed random folks, and choosing to quarantine the old, each save about 18% of life-years lost. Combining those policies, via quarantine the old and deliberately expose the young, saves about 43%.

For all but the last two options in the table, the optimal age cutoff had 24% being “old”: healthy men 60+ and women 65+, and also unhealthy men 40+ and women 50+. For the last two options, the optimal age cutoff had 26% being “old, adding in only healthy women 60-64.

The next three columns give percent chances of dying relevant for the deliberately exposed. % Lives/E is about the average % chance of deaths avoided in others per deliberately exposed person, relative to the same quarantine policy but no one deliberately exposed. % Die not E and % Die if E are about the % chances that someone would die if they die not or did become deliberately exposed. The last column Lives/Risk gives the ratio of the decreased chances of death in others over the personal increased chance of death in the deliberately exposed.

In the last two options which exposing the young, one can offer the young a dramatic motivation for choosing to become deliberately exposed. In addition to any cash compensation, or perhaps medical priority for loved ones, each volunteers to choose deliberate exposure saves someone else a 6.5-7.2% chance of death while themselves suffering only an additional 0.20-0.21% chance. And they can brag about having passed strict health requirements to be eligible. Much like a soldier at war, they can credibly claim to be an elite who made personal sacrifices to cause much larger community gains. (E.g., US soldiers in Iraq in ’06 suffered 1/255 death rate.)

Okay, I tried some variations to test robustness. I encourage you to try variations as well:

  1. I tried increasing the quarantine leakage from 2% to 10%.  Here quarantine old, expose none, gives 82% of baseline loss, while quarantine old and expose young has 77%. So a much leakier quarantine gives smaller, but still positive, gains to deliberate exposure.
  2. I tried doubling the quarantine size, and found losses, relative to baseline, of 72.7% for quarantine old, expose none, 80.9% for expose & quarantine at random, and 40.7% for expose young quarantine old. So the gains of deliberate exposure increase with the size of the quarantine.
  3. I replaced the log death function with a two-state function: The first 10K ICU cases per day get a low death rate of 0.4%, while any more get a high death rate of 3%. Results are quite similar. The optimal young/old cutoff turn out to be the same. Adjusted deaths for quarantine old is 82.4% of baseline, for exposing at random is 87.2%, and for expose young and quarantine old is 61.5%. In that last option, each young deliberately exposed saves 1.7% of another life, paying a personal added risk of .07% chance of death. So while the ratio is similar, both amounts are smaller.
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Vouching Fights Pandemics

As I’ve pitched vouching as a general solution to both law and medicine, the looming coronavirus pandemic offers a good and challenging concrete test; how well could vouching handle that?

If you recall, under a law vouching system, each person is required to get a voucher who stands ready to cover them for any large legal liability, including fines as punishment for crimes. Under a medical vouching system, each person gets a voucher to pay for all their medical treatments, and also to pay large amounts to a third party when that person becomes disabled, in pain, or dead. Voucher-client contracts can specific physical punishments like torture or jail, co-liability with associates, and limits on freedoms, such as re travel, privacy, or risky behaviors. 

Regarding a looming pandemic, your voucher would know that it must pay for your medical treatment, your lost salary if you stop working, and large fines if you die or get hurt. So it would offer large premium discounts to gain powers to limit your travel and contacts, and to penetrate your privacy enough to see what contagion risks you might incur. And it would have good incentives to make risky medical choices expertly, such as if to try an experimental treatment, or to accept early deliberate exposure. 

When you live with others who you might infect, or who might infect you, you’d probably also be offered premium discounts to let the same voucher cover all of you together. But there would remain key externalities, i.e., risks of infecting or being infected by others who are not covered by the same voucher.

The straightforward legal remedy for such externalities is to let people sue others for infecting them. In the past this remedy has seemed inadequate for two reasons: 

  1. It has often been expensive and hard to learn and prove who infected who, and
  2. Ever since we stopped holding family members liable for each other, and selling debtors into slavery, most folks just can’t pay large legal debts.

The vouching system directly solves (2), as everyone has a voucher who can pay lots. And the key to (1) is ensuring that the right info is collected and saved.

First, consider some new rules that would limit people’s freedoms in some ways. Imagine people were required to keep an RFID tag (or visible QR code) on their person when not at home, and also to save a sample of their spit or skin once a week? Then phones could remember a history of the tags of people near that phone, and lawsuits could subpoena to get surveillance records of possible infection events, and to see if spit/skin samples on nearby dates contain a particular pathogen, and its genetic code if present. We might also adopt a gambled lawsuit system to make it easier to sue for small harms.

Together these changes could make it feasible to, when you discovered you had been infected, sue those who likely infected you. First, your voucher could collaborate with vouchers of others who were infected nearby in space and time, by a pathogen with a similar code. By combining their tag records and local surveillance records, this group of vouchers could collect a set of candidates of who might plausibly have infected you when and where. 

(Yes, collaboration gains from voucher groups might give vouchers more market power, but not too much, as this can work okay even when there are many competing voucher groups.)

You could then sue all these possible infectors via gambled lawsuits. For the winning lawsuits, your voucher could subpoena their split/skin to see if their pathogen codes match the code of the pathogen that infected you. When a match was found, a lawsuit could proceed, unless they settled out of court. Sharing verdict and settlement info with collaborating vouchers could make it easier for them to figure out who to sue.  

Okay, yes, there is the issue of who would agree to keep RFID tags and sufficient spit/skin samples, if this weren’t required by law. I’ve proposed that the amount awarded in a lawsuit be corrected for how the chances of catching someone varies with the freedoms they keep. Such chances would be estimated by prediction markets. The lower the estimated chance of catching a particular harm for a given set of freedoms, then the higher would be the award amount if they are caught. 

So if, given the choice, some people choose not to use RFID tags or keep spit/skin samples, they may be harder to catch, but they would pay more when they do. (Which is part of why most might choose less privacy.) As a result, clients and their vouchers will know that on average they will pay for the full cost of infecting others. Which could be huge amounts if they infect many others with deadly pathogens. Which would push vouchers to work to ensure that their clients take sufficient care to avoid that. 

And that’s my concept. During the early stages of a pandemic, a system of law/med vouchers would have incentives to try the sort of aggressive case tracing that public health professionals now try. And if such professionals existed, they could collaborate with vouchers. Once the pandemic escaped containment, this vouching system would encourage people to isolate themselves to avoid infecting others, and to avoid being infected. Their freedoms of travel and privacy would become more limited, more like the limits that an aggressive government might impose. 

But exceptions would be allowed when other costs loomed larger, just as economic efficiency demands. Compared to a centralized aggressive government, a voucher system could much more easily and flexibly take into account individual differences in inclinations, vulnerability, and preferences. The choice of freedoms would be made more practical and local, and less symbol.

With vouchers and lawsuits for infections working well to get people to internalize the infection externalities, pandemics might be limited and contained at nearly the level that a cost-benefit analysis would suggest. 

Added 07Mar: Early in a pandemic it is easier to trace who infected you, and it would make sense to let you sue someone who infected you not only for the damages you suffered, but also for the damages you had to pay others who you infected. This could create very large incentives to contain pandemics early.

Later in a pandemic people sued might reasonably argue that they should only have to pay for the harm from someone being infected earlier than they would otherwise have been, which might be no harm at all during a period before the peak when medical resources are becoming spread increasingly thin.

Added 10Mar: If later in an infection it becomes too hard to trace who infected who, even with the above reforms, then it might make sense to have more general crime-law-based rules limiting social contact. Vouching can also do well at enforcing such rules.

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For Fast Escaped Pandemic, Max Infection Date Variance, Not Average

In an open column, … to provide greater dispersion, the vehicle distance varies from 50 to 100 meters, … distance between dismounted soldiers varies from 2 to 5 meters to allow for dispersion and space for marching comfort. (More)

The troop density has decreased through military history in proportion to the increase in lethality of weapons being use in combat. (More)

Armies moving in hostile areas usually spread out, as concentrations create attractive targets for enemy fire. For soldiers on foot, it might be possible to try to induce such dispersion by having a vicious wild animal chase them. After all, in the process of running fast to escape, they might spread out more than they otherwise might. But this would be crazy – there’s no reason to think this would induce just the right level of dispersion, and it would have many bad side effects. Better just to order soldiers to deliberately space the right distance. 

For a very infectious pandemic like COVID-19, clearly not contained and with no strong treatment likely soon, the fact that medical resources get overwhelmed toward a pandemic peak creates a big value in dispersion – spreading out infection dates. But, alas, our main method is that crazy “chased by a wild animal” approach, in this case chased by the virus itself. 

That is, each person tries to delay their infection as long as possible, in part via socially destructive acts like staying home instead of working. Like soldiers running from a wild animal, our varying efforts at delay do create some variance as a side effect. But probably less than optimal variance, and at great cost. 

Yes, delay has some value in allowing more stockpiling. For example, we should (but apparently aren’t) mass training more medical personnel who can function in makeshift ICU tents. But increasing average delay is can be less valuable than increasing delay variance. Even if we can’t just tell each person when to get infected, like telling soliders where to walk, we have several relevant policy levers. 

First, as I’ve discussed before, we might pay people to be deliberately exposed, and covering the cost of their medical treatment and quarantine until recovery. Yes, if their immunity has a limited duration, then we might want to not start deliberate exposure until there’s less than that duration before the pandemic peak. But there’s still big potential value here, especially via targeting medicine and critical infrastructure workers. 

Second, this is a situation were inequality of wealth, health, and social connections is good. In the last few years, many have loudly lamented many kinds of social inequalities that make the low feel ashamed and unloved, resulting in their more often becoming lonely and sick. Some are enough friends and money that they can afford go to all the parties, while others suffer in poverty alone. And no doubt many will cry loudly when such inequality makes the low get infected before the high.

But however bad such inequality might usually be, in a pandemic it is exactly what the doctor should order, if he could. Among a community close enough to share the same medical resources, the more that individuals vary in their likeliness of catching and passing on the pandemic, the better! Those who catch it early or late will do better than those who catch it just at the peak.  So for this pandemic, let’s maybe back off on whatever we now do to cut inequality, and maybe even open up more to whatever we are not doing that could increase inequality. 

In my next post, I’ll describe some simple concrete sim models supporting these claims.

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Deliberate Exposure Intuition

Many have expressed skepticism re my last post on controlled exposure. So let me see if I can’t communicate my intuition more clearly, so we can all examine it more carefully.

Assume we have a virus like COVID-19, highly infectious and substantially deadly, not blocked or cured by any known or soon-coming treatment. It takes up to 2+ weeks from exposure to death or recovery, and advanced medical resources like ICUs can cut death rates. Even with unusually strong quarantine efforts, COVID-19 currently seems to be escaping from its initial region and nation, doubling roughly every week. Even if that growth rate falls by a factor of three on average, it will reach most of the world within a year.

At which point roughly half of the world who isn’t immune gets infected over a perhaps two week period. Medical resources are completely overwhelmed, so ICUs save only a few. And the world economy takes a huge hit; for perhaps months before that point most workers have stayed home from work in an eventually futile effort to avoid exposure. At the worst possible moment, food, trash, cleaning, heating, and cooling may be scarce, increasing the fraction of sick who die.

To deal with this crisis, there are two key kinds of resources: medicine and isolation. With limited medical resources, including medical workers, we can treat the sick, and cut their chance of dying. We also have a limited set of quarantine resources, i.e., places where we can try to isolate people, places that vary in their health support and in their rate of infection leakage in and out. If we put the more likely infected into stronger isolation, that slows the disease spread.

Consider three different policy scenarios, based on three different policy priorities.

First, consider a policy that prioritizes immediate-treatment. This is a common priority in our medical systems today. Each day, medical and quarantine resources are devoted to the individuals for whom they seem most most-effective in keeping that person alive over the next few days. So hospital ICUs hold the patients whom ICUs can most help now. And the best quarantine locations are allocated to the apparently not-infected at most risk of dying if infected. (Such as the old.) Workers are allowed to stay home from work if they think that will increase personal safety.

In this scenario, medical and critical infrastructure workers may not be given priority in quarantines or medial treatment. So medical workers are culled earlier than others due to their extra contact with the sick, and most medical workers may be sick or stay home near the peak of the epidemic, which is a pretty sharp peak. Most workers in critical infrastructure may be home then too, and may have been there a while. Worse, by allocating isolation resources according to a risk of dying if infected, a treatment-focused policy does little to slow the disease spread.

Next, consider a policy that more prioritizes containment. This is the usual priority of public health today facing a new contagious disease. Here more people become more isolated, and the best isolation resources are allocated much more to those most likely to be recently infected, not to those most likely to die if infected. Efforts may be made here to isolate medical workers, even if that results in worse individual treatment.

This priority can make sense given a substantial chance that the disease can be stopped from spreading beyond an initial area. Even if spread seems inevitable eventually, a containment priority also makes sense if that policy makes an effective treatment substantially more likely to be found before this disease spreads to most everyone. Or if more medical or isolation resources can be created in the extra time. Hope springs eternal, and it feels good to assume the best and act on hope.

But what if there is little hope of containing or treating the disease before most everyone is exposed? And what if getting sick and then recovering often gives someone substantial immunity to the disease for a period? After all, if everyone is constantly exposed, the recovered quickly get sick again, and this infection has high mortality, then death is coming soon no matter what. So we must hope for some immunity.

For this situation, consider a policy that prioritizes long-term treatment-resources. Most everyone will be exposed within a year or so, and unless they are immune they will get sick, at which point their chance of recovery instead of death should depend on medical resources, and critical infrastructure, at that time. So this policy seeks to create a pattern of isolation, and possibly deliberate exposure, to increase the average resources available to help people recover when they are sick.

The obvious problem here is that the above scenarios can have a pretty sharp peak in infection rates, overwhelming medical resources at that point in time. And workers who stay home also threaten the availability of other critical infrastructure resources. Yes, if containment slows the rate of growth of the disease, it also spreads out the time period of peak infection by a similar factor. But that could still be pretty short period.

Relative to the containment policy, this long term resource policy would seek to move the time of infection of many people from near the peak, to substantially earlier than the peak. Moving to later than the peak is not possible, if we’ve been containing as much as possible. And the obvious way to infect people earlier is to directly expose them, on purpose.

Of course directly exposing people won’t help spread out the peak if the people exposed are isolated to the same average degree as people are in the containment scenario. That would instead just move the peak to an earlier point in time, and perhaps even make it sharper, by making the disease spread faster. So this long-term treatment policy would have to involve infecting some people deliberately, while giving them much higher than average quality isolation. If their isolation were very good, then they’d use medical resources at an earlier point in time when such resources are more available, without adding much to the overall growth of the disease.

Now, if good isolation resources, and medical resources, were already strained dealing with a flux of likely infected from outside, then there might be little point in adding new infected on purpose. But what if there are many good isolated places available not being fully used to deal with folks very likely to have been exposed, and also available medical resources not fully used, what if recovered folks had little risk of infecting others for a period, and what if we were closer in time to the peak than that average period between reinfections? Well that’s when we might tempted to deliberately expose some, and then to strongly isolate them.

One key idea here is to create a stronger correlation between the strength of isolation of a place and the likelihood that people there are infected. Such a strong correlation allows us to create a population of already recovered folks who are at least temporarily immune. And that can spread out the period of peak infection, so that more medical resources are available to treat the sick. And that can cut the average mortality rate, which means that more people don’t die.

People who work in medicine and critical infrastructure seem especially promising candidates for early deliberate exposure. This is because after recovery they become more available to work during the peak infection period. They are not sick then, and are less afraid of being exposed then, making it easier to persuade them to go to work. The other set of promising candidates are those most likely to die without sufficient help, which seems to be men and especially the old.

And that’s the intuition behind deliberate exposure. Its wisdom depends on some parameters of which we are unsure, and may learn more about soon. So it seems clearer that we should think more about such options than that we should pull the trigger to start one now. And there are substantial challenges in organizing such a policy fast enough, and in gaining sufficient public and elite support to allow it. Maybe this can’t work this time, and must wait until another big pandemic.

But contrary to many loud and rude commenters lately, this option isn’t crazy. And within the next year we may come to see and suffer the full consequences of not working harder to spread out a pandemic peak of maximum infection and medical need.

Added 2p: The obvious easy win policy solution (given that key assumptions hold) here is just to make it easy for people to volunteer for (1) exposure to virus, (2) strong 24 day quarantine, (3) medical help while there, (4) regular checkups afterward. Create a place where people can go to do this, an easy way to sign up legally, and pay to expose and house them there. Maybe even pay them extra if they work in medicine or critical infrastructure. (Btw, as such an option isn’t now available, and I don’t work in critical infrastructure, it wouldn’t help society much for me to just “go infect yourself”, as many have suggested in so many colorful ways. And as I don’t own my family, I can’t volunteer them.)

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Consider Controlled Infection

In many places long ago, in families with many kids, as soon as one kid caught an illness, parents would put the other kids in close contact, so they could all catch it at once. Because it was less trouble to care for all the kids in a family at once than to care for them one at a time.

Should we also consider controlled infection to deal with our current pandemic? Like controlled burns that prevent later larger fires, it might be a good idea to expose some people early on purpose.

Today a coronavirus is spreading rapidly across China, and the world, and many are trying hard to resist that spread. One obvious reason to resist is the hope that the spread can be completely stopped, limiting how many are exposed. However, once a contagious enough virus has spread to enough people and places, this scenario becomes quite unlikely; the virus will soon spread to most everywhere that isn’t high isolated.

Unfortunately, we are probably already past this point of no return with coronavirus. It seems to spread easily, apparently including via people who are contagious but don’t show symptoms. It already seems to have spread from its initial region to infect many people in a great many other Chinese cities and regions (thousands infected, dozens dead). And that’s with keeping everyone home from work, which can’t last much longer. Once this virus comes to infect most of China, it seems hard to imagine a strong enough China wall (a 24-day quarantine for everyone leaving) to keep it from spreading further. Especially since China & WHO are arguing against such a wall, and we already have confirmed a few hundred cases outside China; they’ve doubled every week for four weeks.

Another reason to resist virus spread is in the hope that a vaccine (or other effective treatment) will be available before it spreads everywhere, stopping the spread at that point. There’s some hope for a drug soon to prevent infections, but the odds are poor and if that doesn’t work prospects are dim. Alas “typically, making a new vaccine takes a decade or longer”, and estimates for this case are at least 18 months. That doesn’t include time to manufacture and distribute it, once we know how to make it.

As of yesterday, total known deaths were 1384, a number that’s had a 6 day doubling time lately. (A very different method estimates 7 day doubling.) At that rate, in four months deaths go up by a factor of a million, which is basically the whole planet. So unless long-term growth rates slow by more than a factor of four, there’s probably not time for a vaccine to save us.

If the virus spreads to most of the world, so most everyone is exposed, then the fraction of the world that dies depends how deadly is the virus, which we just don’t know, and can’t control. Maybe we’ll get lucky, and this one isn’t much worse than influenza. But we are probably not so lucky. The fraction of the world that dies also depends our systems of social support, which we can do more to influence.

I’m not a medical professional, so I can’t speak much to medical issues. But I am an economist, so I can speak to social support issues. I see two big potential problems. One is that our medical systems have limited capacities, especially for intensive care. So if everyone gets sick in the same week or two, not only won’t the vast majority get much of help from hospitals, they may not even be able to get much help from each other, such as via cleaning and feeding. Perhaps greatly increasing death rates. This problem might be cut if we spread out the infection out over time, so that different people were sick at different times.

The other related problem is where many non-sick people stay away from work to avoid getting sick. If enough people do this, especially at critical infrastructure jobs, then the whole economy may collapse. And not only is a collapsed economy bad for most everyone, sick people do much worse there. Not only can’t they get to a doctor or hospital, they might not even be able to get food or heating/cooling. Infected surfaces don’t get cleaned, and maybe even dead bodies don’t get removed. Thieves don’t get stopped. And so on. We can already see social support partially collapsing in Wuhan now, and it’s not pretty.

There’s an obvious, if disturbing, solution here: controlled exposure. We could not only insist that critical workers go to work, but we might also choose on purpose who gets exposed when. We can’t slow down infection very much, but we can speed it up a lot, via deliberately exposing particular people at particular times, according to a plan.

Such a plan shouldn’t just expose random people early, as they’d be likely to infect others around them. Instead, groups might be taken together to isolated places to be exposed, or maybe whole city blocks could be isolated and then exposed at once. Exposed groups should be kept strongly isolated from others until they are not longer very infectious.

Those who work in critical infrastructure, especially medicine, are ideal candidates to go early. Such a plan should only expose a small fraction of each critical workforce at any one time, so that most of them remain available to keep the lights on. If critical workers could be moved around fast enough, perhaps different cities could be exposed at different times, with critical workers moving to each new city to be ready to keep services working there.

Such plans can help even if some people who are infected and recover can get reinfected later. As long as being infected gives enough people enough immunity for a long enough time period, that is enough for this plan to spread out the infections over a time period of similar duration, so medical service needs don’t all appear together. Even an immunity of only two months, which is extremely short compared to most diseases, would allow a lot of spreading.

People selected to be exposed earlier might be paid extra cash, to compensate for perceived extra risk. (Maybe X days worth of their usual wages, so as not to especially select the poor.) Or perhaps they could be paid in extra priority for sick associates if medical help is rationed later. (I’d seriously consider both kinds of offers.) We might even be able to implement a whole plan like this entirely via volunteers, though adding that constraint may make a strong plan harder to design. A compromise might be to let city blocks vote on if to be paid to go early together. I’m willing to help in design work on this, if that could help make the difference.

I don’t have a detailed plans to offer, and obviously any such plans should be considered very carefully. Also obviously, such plans might face strong opposition, which could undermine them. If they were designed or implemented badly, they might even make things worse. But the alternative is to risk having large fractions of the population get sick at once, while the economy collapses due to critical workers staying home to avoid getting sick. A scenario which could end up a lot worse.

So authorities, and the rest of us, should at least consider controlled infection as a future option. I’m not saying we should start such a plan now; maybe that drug will work, and it will all be over soon. But if not, we should start to ask when we might learn what could help us decide, what might be a good time to pull the trigger on such a plan, and how to prepare earlier for the possibility of wanting to pull such a trigger later.

Added 17Feb: See also my next post elaborating the intuition behind why and when deliberate exposure could make sense.

Added 03Mar: See also my spreadsheet model, and further discussion.

Added 15Mar: See also elaborations of spreadsheet model.

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