The Risk of Immunity Passes

I argued earlier that if we have Immunity Passes they Must Be Combined With Variolation because “the demand to go back to work may be so strong that some people will want to become deliberately infected. If not done carefully, however, these people will be a threat to others, especially in their asymptomatic phase.” Thus, if we have immunity passes we must also have controlled infection.

In a new paper, Daniel Hemel and Anup Malani run the numbers and verify the intuition:

…Our topline result is that strategic self-infection would be privately rational for younger adults under a wide range of plausible parameters. This result raises two significant concerns. First, in the process of infecting themselves, younger adults may expose others—including older and/or immunocompromised individuals—to SARS-CoV-2, generating significant negative externalities. Second, even if younger adults can self-infect without exposing others to risk, large numbers of self-infections over a short timeframe after introduction of the immunity passport regime may impose significant congestion externalities on health care infrastructure. We then evaluate several interventions that could mitigate moral hazard under an immunity passport regime, including the extension of unemployment benefits, staggered implementation of passports, and controlled exposure of individuals who seek to self-infect. Our results underscore the importance of careful planning around moral hazard as part of any widescale immunity passport regime.


You honestly think that the rest of the world would accept an American immunity passport? Even if it was coated in bleach, no one outside the U.S. is going to touch it.

All the economists who are amateur epidemiologists can always relocate to the latest COVID-19 hot spot and take part in their own variolation experiments I can't wait to see the GMU econ department lead this charge!!!

we bet the nationwide" immunity pass" will not come to pass for this viral pandemic. there instead will be focused& stepped up testing of hot spots

Given that the US military right now is actually rejecting candidates that have contracted Covid-19 in the past, maybe excessive deliberate infection is not the thing we need to worry about right now.

It's always best to keep a check on whether individual immunity even exists. The latest?

But scientists don't know whether people who have been exposed to the coronavirus will be immune for life, as is usually the case for the measles, or if the disease will return again and again, like the common cold.

"This to me is one of the big unanswered questions that we have," says Jeffrey Shaman, a professor of environmental health sciences at Columbia University, "because it really says, 'What is the full exit strategy to this and how long are we going to be contending with it?' "

And for what it's worth , I think people are heavily in favor of lockdown because they recognize that there are few options. That, based on both current scientific knowledge and experience.

If there is no immunity, at least temporarily, than is there any realistic hope of a vaccine? Either way, you're back to the same place of considering COVID an acceptable risk and normal part of life. Maybe then the attention can shift to keeping yourself healthy and boosting your immune system.

The chance of a good herd immunity and a good vaccine are related, yes.

As Ray Lopez says though, a semi-good vaccine taken every season would still help.

a semi-good vaccine taken every season would still help.

This isn't an argument for keeping on the lockdowns, though I suspect you can't figure out why.

The evidence is clear for at least limited immunity. You know this already, so it’s a very weird hill to die on. Based on SARS-1 we can expect 1-2 years. Maybe less.

I’m still not even sure whether herd immunity changes the game theory payoff matrix.

Show your work

You are one weird dude. This is not my invention. This is the position of scientists who I quote.

You on the other hand believe your particular expertise on everything trumps all links into the real world?

Swing and a miss for reading comprehension. It's very much not the position of the scientists you quote. Remember you've been clearly stating there is no evidence for any immunity whatsoever, which would make this Coronavirus truly novel indeed.

But scientists don't know whether people who have been exposed to the coronavirus will be immune for life, as is usually the case for the measles, or if the disease will return again and again, like the common cold.

Individual immunity exists, that's now well established due to lack of reinfection in any individual in the entire world over the last 4 and a half months. Even in your quote there's no doubt as to whether individual immunity exists.

Rather, the question is how long the immunity lasts. Remember ranting two days ago that there's no evidence of the normal short-term immunity like we see in every other Coronavirus? Yeah, that's a stupid hill to die on.

SARS-1 immunity lasted 1-2 years, that's as good an estimate as any. For SARS-2 it might be less, might be more. There's little reason to hope it will last a lifetime based on similar diseases.

Thus, my position remains unchanged.

And the real question is still: does the existence or non-existence of herd immunity even change the payoff matrix?

That's really weird, to accuse me of a reading comprehension fail, when you clearly do not understand what "or if the disease will return again and again, like the common cold" means.

We are all immigrants, now! Yes, it's movement (travel) that spreads the virus. We can't safely lift the lock-down without adopting restrictions on movement. And not only movement of those who are from or have traveled through places like NYC. I don't doubt that if restrictions on movement were adopted, they would be challenged in court. See Eric Posner's essay in today's WP. But unless we are willing to tolerate millions of dead, we have two choices: continuing the lock-down or adopting restrictions on movement. Getting to herd immunity requires the development of a vaccine, and that's going to take a while. The alternative is herd immunity via infection, with millions of casualties. Tabarrok gets it. [An aside, self-infection has risks we don't even know, risks to those willing to self-infect. We are still learning the long-term consequences of this virus. Young children who had mild cases of the virus are developing symptoms of a form of toxic shock, and several have died as a result.]

How many times do people read past the science? Can you explain it to me ray? If the scientists say they aren't even sure individual immunity exists, why do people keep talking about herd immunity?

Maybe people are not scientifically grounded enough to know that individual immunity is a necessary precursor to herd immunity?

Some say this out of an abundance of caution. . They just mean it’s not proven beyond a reasonable doubt. Is it likely , very much yes. It is for SARS-Cov-1 antibodies persist for about 2 years.
For SARS-Cov-2 it has been shown, IgG antibodies are still there 1 month after recovery.
There’s no evidence that people get reinfected. The “ reinfected” in South Korea turned out to be false positive.
If there’s no immunity why are there 120 vaccines candidates in development for Covid-19 ?
Is it a a waste of time? , no It shows scientists believe some useful immunity is quite likely
How long will it last and how effective is not known. It has already been proven that the Sinovac vaccine is protective in in Rhesus macaques.

I'm not sure we have a poll on "scientists believe some useful immunity is quite likely" but let's leave that aside for a moment.

When Jeffrey Shaman, a professor of environmental health sciences at Columbia University, says:

"This to me is one of the big unanswered questions that we have, because it really says, 'What is the full exit strategy to this and how long are we going to be contending with it?'"

I don't take him to mean we wait forever. I take him to mean we wait a relatively short time until this question is answered.

IOW current policy should always be contingent on current understanding, and not making a wild bet that one particular chance is our only chance.

Here is a very recent study ( May 5) in New York on 1343 patients. One of the authors is Florian Krammer who is a very respected virologist
I quote the authors:
"In contrast to some of the prior literature on formation of antibodies, over 99% of the patients who self-reported or had laboratory documented SARS-CoV-2 infection developed IgG antibodies using our assay. Additionally, our findings suggest that IgG antibodies develop over a period of 7 to 50 days from symptom onset and 5 to 49 from symptom resolution, with a median of 24 days from symptom onset to higher antibody titers, and a median of 15 days from symptoms. This suggests that the optimal time frame for widespread antibody testing is at least three to four weeks after symptom onset and at least two weeks after symptom resolution. In our survey, we did not find evidence for a decrease in IgG antibody titer levels on repeat sampling. Although we do not yet know what, if any, immunity is conferred by or the duration of the IgG response, at this time it seems likely that IgG to SARS-CoV-2 may confer some level of immunity based on what is known about viral immunity to other pathogens"

"Although we do not yet know what, if any, immunity is conferred by or the duration of the IgG response, at this time it seems likely that IgG to SARS-CoV-2 may confer some level of immunity based on what is known about viral immunity to other pathogens"

Right. I certainly understood that when I woke up this morning. But my main frustration was that the US is not taking strong action now, and that in the popular culture a faith in herd immunity is taking on a cargo cult aspect, blocking such action.

Indeed popular culture is drifting toward "open up" based on that faith.

Which means that if either it isn't there, or if it comes at too high a cost, we are doubly screwed.

Why do people use the unimaginative anonymous name? I can't tell if they are arguing with themselves. How hard to think of a unique pseudonym?

The goal is herd immunity, which can come one of two ways: infection or a vaccine. Lifting the lock-down long before the vaccine is developed means we are making a choice, herd immunity via infection.

I'm afraid you just don't understand the science then, but I won't be too hard on you. I will treat you as a placeholder for most Americans?

@anon, seems you are confused, possibly over thinking it. FYI, herd immunity is used colloquially both for with and without a vaccine.

I don't think so, no.

I'm very much afraid that too much of the country is operating on the "it's a virus, so there is immunity" level of thinking.

And that is roadblocking efforts that would save lives regardless of whether herd immunity or a virus lies in our future.

"immunity or a vaccine lies in our future."

Re: Herd Immunity

What is the herd when you live in a world with international travel.

Say an isolated country achieved herd immunity and compare that to a country have the same percentage of infected and recovered persons but there are people going into and out of that country on a regular basis.

A bigger her is inevitable, making a "national" or local herd immunity useless.

Would it have been wise to seek herd immunity for Ebola or would it have been better to eradicate at the source. Same with H1N1.

Will Italy have herd immunity if the 60% nationals who were exposed get constant doses of visitors who were not, including Chinese tourist boats.

are probably not gonna wanna let rayward hold their place because his statement "The goal is herd immunity, which can come one of two ways: infection or a vaccine. Lifting the lock-down long before the vaccine is developed means we are making a choice, herd immunity via infection."
is reductive and then he fubars orwell again

rasumussen poll reaffirms "liberals more likely to snitch"

Orwell believed that when the language used becomes vague or meaningless (e.g., when failure is success) in order to hide the truth rather than express it, the absence of meaning or clarity becomes a "contagion" which spreads to those who do not intend to hide the truth but have become infected by the contagion. We are witnessing two contagions in America.

The much bigger long term risk is that once established (never let a crisis got to waste), such "temporary" controls will metastasize beyond COVID status to include a variety of politically out of favor activities.

China is already doing this - restricting travel, internet access, employment, education for you and your kids, even pet ownership - on the basis of actual or reported behavior.

What you're really saying is that there is always a background problem or paranoia.

That's always a danger but that's why a constitutional democracy with checks and balances in the way to go. The Supreme Court has long held that state and federal governments can violate individual rights in all sorts of days during a pandemic just as it can do so during a war or insurgency. Leaders who seek to extend or exploit these exceptional measures beyond their original purpose should expect to receive push-back in the courts and at the ballot box.

According to the always reliable media offerings the fatalities caused by the Covid-19 virus, and its complications, are concentrated by far in the geriatric portion of the population, actually those running for or already occupying public office. Wouldn't it be more sensible to "lock-down" the aged and allow the younger and healthier to continue with their lives? The thirty-somethings aren't required to give up their driving privileges because they have a statistical likelihood of prostate cancer, heart attack, stroke, rapid onset dementia, diabetic seizures and malignant mesothelioma, among the many reasons the super-annuated depart this vale of tears. The response by governments, particularly the pseudo-democratic versions, has been to use the epidemiological models to justify the only tactics possible for them, lock-down and travel restrictions.

As of May 9, in Minnesota there had been 558 fatalities attributed to Covid-19 or its complications. Of these 449 had been residents of nursing homes or long-term care facilities.

From "The Verge", Oct. 23, 2019:

Nearly 36,600 people died on US roadways last year, a decrease of 2.4 percent from 2017, according to recently released figures from the National Highway Traffic Safety Administration. The fatality rate per 100 million vehicle miles traveled also decreased by 3.4 percent, from 1.17 in 2017 to 1.13 in 2018. The NHTSA says it is the lowest fatality rate since 2014.

That all sounds encouraging, but it’s really only good news for those of us driving or riding in cars. Everyone else, especially vulnerable road users like pedestrians and bicyclists, is being killed at an alarming rate. The number of pedestrians killed — 6,283, an increase of 3.4 percent from the previous year — was the highest such number since 1990.

Cyclists are faring even worse: 857 were killed in 2018, an increase of 6.3 percent. Female cyclists are especially at risk: the number of women killed while cycling shot up 29.2 percent in 2018, compared to just 3.2 percent for men.

May 10, US fatalities attributed to Covid-19 virus: 79,707

Capacity of AT&T Stadium, Dallas, Texas: 80,000

‘Shocking’: 66% of new coronavirus patients in N.Y. stayed home: Cuomo

MAY 06, 2020

ALBANY — The majority of recently hospitalized coronavirus patients in New York are people who have followed the precaution of staying home, Gov. Cuomo said Wednesday.

The governor said it was “shocking” that 66% of new coronavirus hospitalizations are people who are either retired or unemployed and not commuting to work on a regular basis.

“This is a surprise: Overwhelmingly, the people were at home,” Cuomo said during a briefing on Long Island. “We thought maybe they were taking public transportation, and we’ve taken special precautions on public transportation, but actually no, because these people were literally at home.”

Alex, this notion is truly idiotic. If you don’t know why, please review 5th grade level civics.

There are laws which will put you in jail if you take actions that would deliberately injure another.

For example, a hepatitis C person deliberately spitting at a police officer.

Deliberately getting sick and moving in the community could also land you in jail for the that reason, as well as another.

There are other laws that would apply:

" The Justice Department gave federal law enforcement officers across the country the green light to use U.S. anti-terrorism laws to investigate and prosecute people who attempt or threaten to intentionally infect others with the coronavirus.

In a memo to the nation's 93 U.S. attorneys and the heads of federal law enforcement agencies on Tuesday, Deputy Attorney General Jeffrey Rosen detailed the tools available to crack down on intentional spreading of the virus, as well as a slew of other crimes related to the pandemic."

So, that would mean a person who deliberately became infected and circulated could be wearing a different type of passport: a passport to prison or jail.

Now, if you did want to get covid, you should plan on working in an ER, volunteering to clean jail cells, or flying in an airplane.

Once getting sick, you must isolate for 14 days. Otherwise, you are breaking quarantine.

Also, your dependents also should check your life insurance policy if you choose to get deliberately infected and die, and whether they will get any benefits, and while you are at it, you might was well check your health insurance policy for exclusions at the same time.

Society often sets it up so that when someone could impose a negative externality on others there will be a cost.

Here is what South Korea is doing. This is what we should be doing, including for domestic air travel, right now:

Perhaps Alex understands that herd immunity and variolation or actually dated by a solid understanding of individual immunity.

But without this, loose talk about herd immunity is actually counterproductive. Is Tyler says


As Tyler says, public choice in the political economy matters. All this talk about a thing that may not exist is very much distracting us from the immediate actions that matter.

from the twitter thread:"I feel pretty confident that the government knows everyone who has coronavirus..." Yup, because there's no asymptomatic spread in S. Korea. This makes no sense, really. If the government knows, then why are they allowing the epidemic to continue? But of course they don't know. They just have a method for dealing with the spread.

Google's control panel claims SK has 10,874+34 Cases, Recovered 9,610, Deaths 256.

10874+34-9610-256 = 1042 active cases to track?

South Korea isn't testing everyone with flu like symptoms- not even close- they ran only 3,600 tests yesterday, and the trend in testing is down, down, down- far more than would be expected if you were just going by symptoms alone. That is how South Korea got under 50 new cases/day- they just stopped testing anyone who couldn't show a connection to an active case. Seriously, they are running fewer tests per day than my state of Tennessee.

In fact, every single state in the U.S. has run more tests/capita than South Korea has.

You’re looking at the wrong metric for testing. It’s not tests per capita, but rather the % of tests which are negative. I believe Korea has 95% of tests coming back negative. They have been actively seeking out asymptomatic people since Feb or earlier I believe.

Their numbers have extreme fidelity.

Kinda Related Modest Proposal:
Airlines offer rapid Covid testing (say within 3 hours). You pass, you're on the flight... and you know that everyone else is safe too.
You flunk... Don't Pass Go, Go Directly to Quarantine and No Refund.
Same for return flight. Customs checks passports and test results on both sides.
Full capacity, safe flights, without fear or disease.

That won't work.

First, we'd need a test that's both quick and extremely reliable. We don't have one yet. Even when we do, there will be a long lag before it proves itself and is fully trusted.

Also, "No Refund"? That's foolish and unjust. Anyone with symptoms gets screened out at an earlier stage. You'd only test people who are asymptomatic and therefore don't know they're infected. And what about false positives?

Also, plane tickets are usually bought weeks in advance. What if you get infected in the meantime? Last-minute tickets are always much more expensive, so that's no solution.

And what do you do during the three hours you're waiting for your test results? Airports aren't set up to isolate every individual passenger. What if you receive a viral load from a fellow passenger in the airport terminal, but it takes a while to develop enough of an antibody response to register when you're tested?

So one way or another, destination countries will have to insist on isolating arriving passengers for at least a few days, and likewise upon your return home. Most trips will cost you anywhere from one to four weeks of isolation. There will be no frictionless travel except between mutually-trusting green-zone countries like Australia and New Zealand.

I have a suggestion for a lower impact solution. Tell everyone to go to a drive-through testing center 24hrs before their flight. Then go home. Then get results by text. If you test positive you get a refund or voucher plus a bonus! You are automatically enrolled in COVID-19 benefits.

Test results can be available quickly
I'm not wedded to no refund. Treat it as a change in the ticket and use the usual results for that.

>Also, "No Refund"? That's foolish and unjust.

What's your alternative? The airlines just eat the loss??

Either that, or some insurance covers it. The other alternative is not to fly.

Or to just take the risk that we'll fail the test... just like we all do for the countless reasons other reasons why trips may get semi-involuntarily cancelled.

AlexT proposes nonsense on stilts. There's no hard evidence previous infection by C19 provides long term future immunity. Since C19 is a chimeric virus with huge gain of function, there's a fair chance it provides no such immunity, and in any event, C19 mutates every year like the common flu. Constant vaccines will be needed every year.

So. We don't know the medium and long term complications nor their rates of incidence. We don't know how long having had the disease confers immunity. We don't even know if it does confer immunity. And we don't know which antibodies (if any) and at what concentration indicate with a good degree of certainty a person will be immune for an unknown period. And yet you persist. Have you specified how long immunity need last (on average) for your proposal to have merit? Assume we can determine that a person is immune, even though that fact is not in evidence. How long is long enough? How would we revoke such a passport? Does their blood titer need monitoring? etc. etc. etc. I don't even know whether even if my immune system can resist the virus sufficiently to avoid symptoms, whether that also implies I'm not infectious. Do you? That is: does 'being immune' imply not being an active spreader? Where's your data?

Immunity passports are never going to happen.

counterexample: yellow fever cards

For vaccination.

i.e., you're unlikely to be a carrier....just like an positive antibody test.

"... run the numbers and verify the intuition": a calculation cannot verify an intuition - you'd need the outcome of an experiment to verify an intuition. The calculation, I'll grant, might support the intuition - and that's better than a slap across the face with a wet fish.

I am in my 50s, but would consider self-infection if variolation proved to work and I was assured decent medical care if necessary.

I have, say, 30 good years to live. The risk of death from infection is, say, 1%. One year of lockdown is 3% of my life. Three years of lockdown vs. one year of life ... seems like about an even trade. Especially since the lockdown happens when I'm youngest, and the lost life years are evenly distributed over the next 30.

Seems like about an even trade to me.

If I were in my 20s, with risk of death 0.3 percent (say), I would be giving up (say) 2 months of life for 1 year of lockdown. Again, about an even trade.

If I were 80, with (say) a 5% chance of death? Maybe not.

Re: If I was assured of decent medical care if necessary

That's the free rider problem, or the negative externality problem: In pursuit of a benefit to oneself, there is a cost imposed on others.

In the cost calculations, you need to include the costs imposed on others, not just yourself. Those others may be your family who will now have to fend without your help.

If you do not want to impose an externality, or make a trade, sign up for a vaccine test.

If you mean for under 30s, maybe. Over 30? No way! I have taken care of too many severely ill 30-year-old Covid patients. It is NOT like a bad flu, unless your flu lasts for weeks and you are too weak to leave your bed. So far have not had a patient in their 20s.
This is a horrible idea.

You're permanently banned from joining the military if testing positive. Some people might think that is a plus, but maybe the military knows something you don't.

Policy has been updated to banned if hospitalized.

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