In this paper, I suppose that herd immunity is the exit door from the pandemic. In the absence of a vaccine, attaining herd immunity requires to expose a fraction of the population to the virus, and to recognize that some people in this targeted population will die. Determining who should be exposed to the virus to attain the herd immunity is a crucial policy issue. . .Some individual characteristics such as the age or the existence of co-morbidity have been shown to have a huge influence on the lethality of the SARS-Cov-2. For example, Ferguson et al. (2020) report that the covid infection-fatality ratio is 0.002% for individuals less than 10 years old, and 9.3% for people aged 80 years and more. Given this 4650-fold difference in mortality risk, it may be desirable to expose less vulnerable people first in the hope of building the herd immunity before relaxing the protection of the more vulnerable people.
Pointer from the diligent John Alcorn. What is your guess as to when the lockdown debate gets shifted toward these terms?
2. Philipp Kircher and others write,
When the young engage in more risky behavior, they reduce the time until herd immunity is reached. The young then take a larger share in the infections needed for herd immunity, which is amplified if the old can shield themselves for short periods by voluntarily engaging in stronger social distancing.
Our calibrated benchmark indicates that the positive externality is indeed present in the absence of a vaccine/cure. This can limit and sometimes negate the effects policies such as temporary shelter-at-home policies. It also indicates that its strength is limited, as it is quickly overpowered through other channels, for example in extensions with scarce hospital beds which the risk-taking young exhaust through their behavior. The interactions by age indicate that it is an important margin to consider, that the effects are not trivial, and that age-specific policies might be warranted.
Another point from JA, and another example of where I think the debate needs to shift. Of course, I should not that this paper uses a simulation model, which I don’t think adds value to the discussion.
3. Daniel Klein and others defend Sweden.
Swedish authorities have not officially declared a goal of reaching herd immunity, which most scientists believe is achieved when more than 60 percent of the population has had the virus. But augmenting immunity is no doubt part of the government’s broader strategy—or at least a likely consequence of keeping schools, restaurants, and most businesses open. Anders Tegnell, the chief epidemiologist at Sweden’s Public Health Agency, has projected that the city of Stockholm could reach herd immunity as early as this month. Based on updated behavioral assumptions (social-distancing norms are changing how Swedes behave), the Stockholm University mathematician Tom Britton has calculated that 40 percent immunity in the capital could be enough to stop the virus’s spread there and that this could happen by mid-June.
We could frame the “opener” vs. “closer” debate this way: openers wish to achieve herd immunity sooner rather than later, while closers wish to achieve it later rather than sooner.
Herd immunity is costly to achieve, in that some people will get sick and die in the process. Closers believe that we should not be trying to hasten to get to herd immunity, presumably because there is an alternative endgame that can be achieved within a reasonable time frame. As one commenter put it,
Which strategy we should pursue depends upon our wild-assed guess as to whether a vaccine or significantly better treatment will appear before civilization ends in economic ruin.
It seems kind of odd to frame these as the only two choices, when test, trace, and isolation of the infected is also an option. Indeed, I thought that was the whole point of the lockdown, to get us back to where we had been originally before we bungled the initial response. That is, to pull a Taiwan. (Or frankly South Korea, where despite the press and without any fancy Bluetooth tracing applications, they have very quickly discovered and isolated even all those infected in a mother of all super-spreading events.)
Of course, it seems as though we’ve squandered that time again and so maybe test and trace is no longer a viable option either.
Yes, yes, yes.
When the article says “We could frame the “opener” vs. “closer” debate this way: openers wish to achieve herd immunity sooner rather than later, while closers wish to achieve it later rather than sooner.”, where does South Korea fit? What about Japan, or even Germany now that it’s reopening?
The obvious third route is to beat this disease the way we beat SARS, Ebola, etc.: by eradicating it through contact tracing and heavy testing. Many “Closers” don’t want to achieve herd immunity at all.
That might have worked in February. Now it’s wishful thinking. Way too many people have it. Now you committing huge resources to chasing a cold.
If herd immunity is going to be the “exit door from the pandemic,” then where is it to be built up? The paper suggests among the young, due to their much greater resistance to bad outcomes – this even though there will be some mortality among them.
Building immunity among the young makes sense; they will be around to benefit should there be further outbreaks. The elderly who depart this vale subtract from herd immunity.
There is good reason to suspect that acquired immunity to coronaviruses doesn’t last very long. That means that herd immunity may not be possible; we’ve never achieved herd immunity to the common cold (also a coronavirus). Coupled with the mild-but-apparently-permanent lung damage associated with Covid-19, that’s potentially bad.
Here is the link that I messed up in the above post:
https://www.medicinenet.com/script/main/art.asp?articlekey=231127
I think the Swedes just wanted to avoid the embarrassment of lockdown non-compliance in their immigrant enclaves.
#1 “What is your guess as to when the lockdown debate gets shifted toward these terms?”
Not guessing for it. Been praying for it.
(If the media outlets are any indication, they started moving on to other topics late last week. That’s my leading indicator that the tide is starting to turn.)
Another day with excellent numbers in terms of new cases, tests, and deaths. Lowest Tuesday deaths since March 31.
Deaths for Monday-Tuesday last week went from 912 to 2527. It was 837 to 1510 this week.
Fewest deaths in a 7-day period since the weekend ending April 9.
I think the numbers may improve so quick that the lockdown discussions just get mooted as people increasingly ignore them.
Also, 2.1 million tests performed over the last week. The scale up in US testing has been pretty extraordinary.
I’m getting a covid19 test tomorrow at Quest Diagnostics, which I signed up for despite not having any symptoms or connection to the disease. I signed up today online in 15 minutes.
I believe these came online about a week ago, but if we’re at a point now where anyone can schedule a test for themselves within 2-3 days and infection rates which are heavily trending downward, we *might* be at an inflection point where living with covid becomes manageable.
If you’ve been paying attention to the daily numbers, this is perhaps the best 3 day stretch we’ve had for the entire pandemic in terms of path-correction.
I was trying not to jump to too many conclusions based off the last two days and wanted to see what kind of bounce back we’d have today, but it was very modest and most of the states have reported in.
If we have two more weeks of this, I think the public sentiment towards ending the lockdown will be quite strong.
This looks like the case in other countries as well.
Even when the dreaded and eternally coming “next wave” comes. It’s smaller. Less pronounced. And medical systems are adapted to them.
Probably a combination of better more experienced treating physicians (if nurses and doctors haven’t improved in how they treat cases since March then shame on our heros). Some higher level reached on the spectrum of herd immunity. The harvesting effect. And people being more educated about the disease and how to avoid it.
#1 I’d be much more inclined to support such a plan if the children/grandchildren of the plan designers and of members of congress were among the herd participants. Why do i suspect the chances of that are zero?
Excellent blogging. Barring a miracle vaccine, the least-bad option is sequester the old and go back to normal.
Regarding herd immunity, it is often said that 60-80% people that are infected clear the virus and WHO has also stated that truly asymptotic people have not known to be infectious.
Lots of asymptotic people might have cleared the virus without developing antibodies to the coronavirus, simply through the action of innate immune system. These people will not show in antibody tests thus it is quite possible that the antibody tests seriously underestimate the prevalence of immune people.
I’m sorry to see that you are signing off. I appreciate your efforts, even if I can’t understand all of the information you so generously have shared.
My faith give me hope, despite the horrors yet to come.
It is good that you have chosen to spend more time in physical activity. I hope that you will choose to resume your blog at some time in the future and that I will be among your readers.
Peace.
Dr. Kling,
This message is in response to your “Signing Off” post, which is closed for comments. I am a late 40’s sales and marketing executive for an international firm, and an enthusiastic amateur economist. I happened upon your work a decade ago and have been following you, and encouraging friends to do so, ever since. I buy your books and I read your posts.
As is your wont to avoid current topics, I have usually caught up with your blog every two weeks or so. But during the current pandemic, as you have changed to posting daily, I have started reading daily. And not just daily: of all the news sources and blogs I subscribe to yours is first read and must read.
I do this because, just as in economics, you bring a sensible, thoughtful, and pleasingly heterodox approach to the other practical and intellectual questions of the day. You improve my thinking and open up new perspectives, and I am grateful for it.
While I respect your decision to go offline for now, I hope that circumstances evolve so that one day soon you will entertain the possibility of coming back. If and when you do, I eagerly look forward to that day.
Sincerely,
A Fan
+1 Arnold is a national treasure (even when we royally disagree).
I’m sure he needs and deserves a break from it all. And, what more is there to say at this point?…he has pretty much said it all in terms of the virus.
Hoping that he will come back online at some point in the future when he is ready.
In the meantime, looking forward to re-watching “One Flew Over the Cuckoo’s Nest.” Nurse Ratched wouldn’t want it any other way.
And, he got out at his apex. While there are many many must read posts, “Why R we mindless?” was probably my personal favorite.
I doubt that ASK does curtain calls, so go back and relive his best posts. There is a ton there.
+2!
Dr. Kling,
I agree with Charles and TB 100%.
One additional thing is that you bring out the best in your commenters. I find that at least 80% of the comments are well thought out and make good points. When I do decide to comment myself I usually find that someone else has said the same thing only better.
In contrast, Marginal Revolution (an excellent blog) reading the comments is like being in the middle of a high school put down contest.
Stay safe
Along with Charles Roberts, TB in Chicago, and BillT, let me thank you for the blogging you have done, and express the hope that you will return soon.
I want to add my voice to the chorus of your fans. I’ve been following you since I graduated college, back when you were blogging with Bryan Caplan at Econlog. No matter what the forum, I have always found yours to be among the most insightful and thought provoking voices. I know that I am a better person for having engaged with your work. I wish you only the best, and whether you return to writing or not, I will remain forever grateful for all that you have already given.
“I know that I am a better person for having engaged with your work.”
Well said, thank you! I wholeheartedly agree.
Arnold, like you I have grandchildren. Today I drove to the exurbs and rode my bike. Life is good. But, d*mn, I miss your posts.
I enjoy this blog and often recommend it to friends and colleagues. Like the others, I hope you come back to blog again.
In the meantime, rest is good.
I saw in your next post that you are signing off, at least for now. I also saw that comments there are shut off, so I am leaving you a comment here.
I want you to know how much I appreciate all of the work you have put in to keep this blog going for so long.
I am nobody special academically. I am not an economist and I’m not a professor of anything. I’m on furlough right now, but when I’m working I go into people’s homes to run safety tests on their heat and hot water systems, check the wiring, look for mold and asbestos, and advise them on how to make their homes safer and more energy efficient.
A lot of what I know about economics comes from you. I have followed you, and Tyler, and a few other people (I used to read Megan McArdle until she went behind a pay wall) since you blogged at Econlib. I have also read Crisis of Abundance and the Three Languages of Politics. I found them both to be incredibly insightful, and helped me to really understand some of what is going on in the world. And your typical “different take” on things has given me the knowledge and understanding to call “Bullsh!t” when I see things on the news that reflect how poorly the media sometimes understands what they are reporting on.
I understand that you are frustrated, and why. I just wanted to say Thank You.
Well said, Marc. I agree completely.
Arnold had been one of three voices I found myself repeatedly turning to for reasoned skepticism in this period (@baldingsworld and @lymanstoneky on twitter are the other two for those interested). He will be missed.
Marc A Cohen, check out Arnold’s Specialization and Trade. A lot of it has appeared on this blog but it’s even better as an extended argument.
Arnold, this reading will give you peace of mind
https://www.project-syndicate.org/commentary/governments-cannot-admit-covid19-herd-immunity-objective-by-robert-skidelsky-2020-05
Yes, by Skidelsky, the caretaker of Keynes’ legacy.