Congratulations to New Zealand

New Zealand hit zero active cases today, so it appears to be entirely Covid-19 virus free. I visited NZ in January, and very much wish I were there now. (I’d be there now if they’d take me without a quarantine.) Good for the Kiwis!

Note that New Zealand will occasionally have a few imported cases, as they wish to restart tourism. Fortunately, tourists from East Asia and Australia don’t pose much risk. And there is great value in ordinary Kiwis being able to go about their lives without fear of infection.

I am currently in a fairly large hotel in Tucson. The hotel has closed the restaurant and swimming pool. If you want maid service you need to request it. (I don’t.) The place is almost empty—I feel like I’m in one of those post-apocalypse films. Yes, Tucson is normally quiet in June, but nowhere near this quiet. It’s my first time out of Orange County since January, and this trip is making me more pessimistic about the US economy going forward. AZ has “reopened”, but life here is far from normal. As I keep saying, it’s not about “lockdowns”.

(BTW, I don’t need maid service, never did. Indeed the whole idea seems pointless to me. I’d rather hotels dispense with maid service for people staying a week or less; it would make rooms cheaper.)

They say there are fewer cases in summer because people go outdoors. In Arizona, people go indoors in the summer:

New Zealand has about 5 million people. Up next is Taiwan (24 million) which has only 6 active cases, and may soon have zero.

Lots of European countries are sharply reducing their active caseload.

Then there’s the US. What the #@&% is the plan? Are we going for herd immunity? Or a low active caseload as in Germany? Or something else?

We seem to be just muddling along, with no plan at all.

A big depression or a couple hundred thousand deaths?



51 Responses to “Congratulations to New Zealand”

  1. Gravatar of P Burgos P Burgos
    7. June 2020 at 19:28

    “ We seem to be just muddling along, with no plan at all.”

    It is the US. If you want different outcomes, you need a different culture and different political institutions. It’s starting to look like the Argentina of the 21st century.

  2. Gravatar of Jason Jason
    7. June 2020 at 19:32

    In other news, apparently the medical establishment has been infected with the “social justice” ™ virus. I saw images of medical personnel cheering on protesters. Apparently, covid hits you in Church, but not when protesting racism.

    And lefties wonder why “experts” are distrusted by conservatives!!!!!?

  3. Gravatar of rwperu34 rwperu34
    7. June 2020 at 19:35

    Glad to see somebody besides me state the obvious…people in AZ head indoors in summer. Now if only someone in a leadership position can state the obvious…it’s not safe.

    We have virtually no contact tracing.

    Mask wearing is ~25-35% based on what I see when I go to the grocer.

    Testing is inadequate for the level of cases we had, let alone where we are now. That’s not to mention where we’ll be in a few weeks.

  4. Gravatar of Michael Sandifer Michael Sandifer
    7. June 2020 at 20:01


    Most decent, sane people in the world support the protestors. Haven’t you noticed this is a worldwide phenomenon now? This is well beyond American left and right politics.

    This could be the beginning of Scott being proved right about the liberal backlash in response to Trump. I agreed with him at the time, and stated it might be similar to what happened in California a generation ago, though maybe less extreme. I now wonder if there won’t be a bigger backlash than I even imagined. Republicans are at risk of being in the wilderness for a generation or more.

  5. Gravatar of Michael Sandifer Michael Sandifer
    7. June 2020 at 20:03

    P Burgos,

    I’ve made similar observations many times. Argentina was the 12th wealthist country on Earth at the turn of the 20th century. Since Peron populism took hold, it’s been a basketcase, going bankrupt in recent decades every 10 years or so, usually coupled with high or even hyperinflation.

  6. Gravatar of Gene Frenkle Gene Frenkle
    7. June 2020 at 20:32

    Completely off topic yet topical—so when I search “Keynes reparations” the Treaty of Versailles comes up so that did me no good. But in traditional Keynesian economics, in our consumer spending economy with a robust stock market, wouldn’t reparations for slavery simply create more demand for consumer products and services?? So just with respect to traditional Keynesian economics is there any downside to reparations for slavery in our economy??

  7. Gravatar of Market Fiscalist Market Fiscalist
    7. June 2020 at 20:39

    ‘Then there’s the US. What the #@&% is the plan? Are we going for herd immunity? Or a low active caseload as in Germany? Or something else?’

    I think I got the answer recently from a favorite blogger of mine:

    The US is going for a quick economic recovery and recent record high stock valuations show its succeeding, I guess.

  8. Gravatar of Grant Grant
    7. June 2020 at 22:31

    A true herd immunity strategy would be reasonable for the U.S., given the difficulties of test-trace-contain here vs. say Europe. However it would involve actively assisting the elderly, other at-risk groups, and their care-givers with isolation until antibodies or a vaccine is available. We don’t seem to be doing that.

    (Sweden by the way is getting better at that; case growth among the young there is growing, while among the elderly it’s shrinking)

    I’ve been following this virus pretty closely since late Jan, and I’m pretty sure our current (as in the last week or two) level of social distancing is unsustainability high. Florida’s data is detailed and timely relative to other states’, and I’m seeing a spike in cases among people < 60 years old over the last week (perhaps from the protests). So far it has not crossed over in to the elderly.

    If we ever had a viable national strategy for re-opening I never saw it.

    With many mass gatherings coming back and millions of people now protesting, I think the political will to subdue the economy again will just not be there. I fully support the protests, but also every business owner who wonders why they just endured everything they did.

  9. Gravatar of Grant Grant
    7. June 2020 at 22:37

    Market Fiscalist,

    Our president obviously cares about the stock market more than most other things. He did not react strongly to covid until the market started to tank. I believe he looks at the recovering stock market as a sign the U.S. is on the right path.

    I could be worse; he could only trust his own narcissistic opinion. Sadly the market is a bit dysfunctional right now, as evidenced by it being ridiculously slow to pick up on the danger posed by covid at the start of this year.

    I wonder how much GILD Trump owns (or owned).

  10. Gravatar of Postkey Postkey
    7. June 2020 at 23:20

    “New Zealand hit zero active cases today, so it appears to be entirely Covid-19 virus free. I visited NZ in January, and very much wish I were there now. (I’d be there now if they’d take me without a quarantine.) Good for the Kiwis!”
    Good for N.Z. {population 4.88m}.

    However, if the statistics are to be believed {?}, Beijing, has a population of 21.5m has been free of Covid-19 after 9 deaths! Shanghai, with a population of 24.2m has been free of Covid-19, with 7 Deaths.

  11. Gravatar of Jens Jens
    8. June 2020 at 00:49

    What the #@&% is the plan?

    Just stay calm. It will go away.

  12. Gravatar of Alex Schell Alex Schell
    8. June 2020 at 04:06

    “I’d be there now if they’d take me without a quarantine.”

    Not in equilibrium you wouldn’t 🙂

  13. Gravatar of ssumner ssumner
    8. June 2020 at 06:03

    Market, It remains to be seen whether we will have a quick recovery.

    Grant, Keep in mind that the depression was not caused by anything the government did, it was caused by voluntary social distancing. There’s no law preventing people from staying at the hotel I’m at, but it’s almost empty.

    Sweden’s also in depression.

    You said:

    “He did not react strongly to Covid until the market started to tank.”

    No. Even after the stock market started to slide he twiddled this thumbs for another three or four weeks.

    Postkey, Yes, but of course China had far more draconian policies than other countries.

    Jens, But what’s the best way to wait it out? And how long do I have to wait?

    Alex. You mean the whole world doesn’t revolve around ME!

  14. Gravatar of Brian Donohue Brian Donohue
    8. June 2020 at 06:43


    Well, the monetary authority has a plan, and it seems to be doing pretty well. I thought you made your career on emphasizing the importance of this policy channel.

    But yeah, the US (and UK) response has been dismal. Plenty of blame to go around in both cases.

    Lars has been quite the contrarian with his virus takes, most recently re: New Zealand. You think he’s all wet on this?

  15. Gravatar of MJ MJ
    8. June 2020 at 07:10

    Seems to me the most effective pandemic strategy has simply been having leaders who didn’t downplay it. The worst performing countries like the US, Britain, Italy, Brazil all had or continue to have national leaders making public statements saying it was no big deal. If a country’s leaders took the pandemic seriously, or at least didn’t actively spread misinformation, then they probably did ok.

  16. Gravatar of Michael Rulle Michael Rulle
    8. June 2020 at 08:11

    One thing I have noticed is how fast, relative to a month ago, is how many more tests “per million” have been tested——up to mid 60s—-increases about 3-4 a day. The last two weeks have seen an almost flat active cases line. More importantly, deaths per day continue to decline, even as cases per day have not nearly as much.The 3 largest states in population have very low deaths per day. Regardless of trend—-their daily death total is about same combined, as N.Y.—-currently.

    It seems reasonable to assume that increased testing is capturing a higher percentage of asymptomatic Covid carriers. Ultimately it is deaths which matter. However, our number annualized even at the current rate is still very high——about 250-275 k although down almost 2/3rds from the high—-much larger decline than new cases which is down about 1/3rd from the high (7 day ave).

    Both are still on the decline. I don’t know if FL, TEX, And CAL understate and/or N.Y. overstates.

    Still much uncertainty——but the NE states are declining fast—-which for some reason my conspiracy part of my brain interprets the former numbers are overstated—I have lived here my whole life and it is just so corrupt. But put that aside—-the death drop will continue to drop relatively fast in NE for whatever reason. WithouT a vaccine we are still at best likely to be at 200k annualized Without a vaccine——which really is very high. I hope it is lower.

    We need to fully open—-if people do not want to participate we cannot do anything about it. But we don’t need to force them.

    Speaking of politics——I am not sure I have ever heard anything as ridiculous as defunding our police forces and replacing them with social workers. Of course that won’t happen anywhere——-we are in the zone of the grotesque “Time of the Season”—-presidential politics.

  17. Gravatar of msgkings msgkings
    8. June 2020 at 08:41

    @Jason: Covid is far more transmissible inside (churches) than outside (protests)

  18. Gravatar of msgkings msgkings
    8. June 2020 at 08:44

    @Jason: Also, Covid is far more dangerous for old people (churches) than young ones (protests)

    As far as not trusting experts, it’s not a mystery. Not every conservative is unintelligent, but the ones who don’t trust expertise are.

  19. Gravatar of Todd Kreider Todd Kreider
    8. June 2020 at 10:01

    “Grant, Keep in mind that the depression was not caused by anything the government did, it was caused by voluntary social distancing. There’s no law preventing people from staying at the hotel I’m at, but it’s almost empty.”

    The odd thing is that I think Scott seriously believes this. Voluntary social distancing = bad for economy, government forced social distancing on 97% of the U.S., = no effect on the economy.

    “Sweden’s also in depression.”

    According to Trading Economics, Sweden’s unemployment rate in April was the same as January, 8.0%. I couldn’t find May’s rate. How can Sweden be in a full blown depression if the unemployment rate has stayed the same?

  20. Gravatar of Brian Donohue Brian Donohue
    8. June 2020 at 10:26

    @msg, “experts” have not covered themselves in glory this year. Many intelligent and interested amateurs have outperformed the experts.

    Also, let’s hope none of those protesters live with older parents or grandparents.

  21. Gravatar of ssumner ssumner
    8. June 2020 at 10:40

    Brian, I don’t think he’s wrong that the virus will return to NZ, I think he’s wrong that this will be a big problem. They can handle a few imported cases. After all, they handled over 1000 cases already. They’ll get to the vaccine next year with less than 40 deaths.

    He overrates the lockdown factor, and underrates the effect of voluntary social distancing.

    Todd. I would not say lockdowns have no effect, but without lockdowns we’d still be in depression. I rarely see lockdown opponents (other than me) acknowledge that fact.

    As far as Sweden, let’s return to the issue in six months and look at output there vs. the other Nordic countries. I predict little difference.

  22. Gravatar of Sean Sean
    8. June 2020 at 11:19

    I would have to disagree with the GOP being in the wilderness for a decade. I could equally argue the left will continue to be in the wilderness.
    1) I’ve moved closer to Trump since the protests. Never liked his rhetoric, but I understand it. I abhor identity politics. And I see a growing movement in the US to silence criticisms and assaults on free speech. I’d prefer a more technocratic government. And I believe I’m one of the few people in either parties that believe the Chinese government has done a great job over the last 30 years and are not a threat to the US. Atleast as it comes to trade issues; maybe theirs a military problem.

    2) A lot of people in private have much different views than what they say in public. I don’t see the big change in opinions.

    3) The left just seems like a mess. They’ve failed to unite as a party. Biden seems like one of the worst POTUS nominations ever. He’s not charismatic and he seems to be in mental decline. The left struggles to develop leaders they can back. And then theres the internal civil wars between old school dems and the woke crew.

    America’s system is terrible for controlling a virus. Power is very diffuse in our society so its tough to unite. And we also lack the benefits of New Zealand of being a small island country.

    Best I can tell the country is united behind herd immunity now. Its not an ideal policy, but we lacked the unity to develop a better policy.

  23. Gravatar of Bob Bob
    8. June 2020 at 11:42

    If consumers don’t feel safe consuming, then they won’t consume. You can throw open your doors and declare quarantine over, and you can lure in the most cavalier folks, but an economy does not run on supply alone.

    16% of the population is over the age of 65
    3% of the population is immunosuppressed
    Many more live with someone in the at-risk categories

    A few million here, a few million there, sooner or later you’re talking about a large share of the population that cannot participate in the Covid-exposed economy. Personal consumption expenditures fell by 1.3% in the depths of the Great Recession in 2009. How much does PCE drop when 20%+ of the population can’t visit restaurants, hotels, or travel?

    The best way to make people feel safe to spend is to eliminate the disease. The next best way is to test and trace so that individuals can self-quarantine. The least best way is to just tell people that they’ll probably be fine. Considering the substantial spike in “pneumonia” cases in FL, TX, and GA, some states are going with the “it’ll probably be fine” approach.

    “An ounce of prevention is better than a pound of cure” may be the understatement of the millennium.

  24. Gravatar of Bob Bob
    8. June 2020 at 11:46

    @Sean, you “abhor identity politics” and yet you endorse the white grievance candidate who heads the party that is 90% white. I hate to break it to you, but the GOP is the party of identity politics. Remember when Trump literally described himself as a “white nationalist”?

  25. Gravatar of msgkings msgkings
    8. June 2020 at 12:08

    @Brian D:

    I would rather hope that those older parents and grandparents already know how to protect themselves, after 4 months of this.

  26. Gravatar of Christian List Christian List
    8. June 2020 at 12:25


    you really know your memes, the taco girl is so sweet. But their is no need for both in the original ad. Hard-shell tacos are disgusting and you know it.

    You are right about NZ.

    You are right about Sweden, too. They seem to do “both” as well. Even their own government says that they are headed for its worst recession since World War II. They expect that their economy will shrink 7% this year. Well, at least they have saved a lot of pension money by now.

    Don’t be so stubborn all the time. The Swedes have “Kurzarbeit” as well, they aren’t really working, but they don’t lose their jobs either. The government is paying most of their salary.

    Not to mention that half Sweden’s GDP comes from exports.

    @Jason and Sean
    I completely agree.

    In any case, it would be an irony of history if voters were to change camps because a black man was killed, in a major American city that has been ruled at all levels by Democrats for decades.

    But in America, as you know, anything is possible.

    But I can also well imagine that this shitshow ultimately benefits Trump. The Left can always go to Trump’s level, he then beats them with experience. He is the king of any shitshow so far.

    I was worried about his bad Corona management and the economic crisis, but now things are looking better economically, Biden is a weak candidate as you rightly say, Twitter is now playing Orwellian Ministry of Truth, and the left is again only doing identity politics. This might actually be the perfect storm for Trump again.

  27. Gravatar of JayT JayT
    8. June 2020 at 13:28

    I think that the increase in cases in Arizona is far more explained by their increase in testing than an actual increase in infections. The rate of case/test has been fairly flat since the beginning of April.

  28. Gravatar of Grant Beaty Grant Beaty
    8. June 2020 at 13:30

    Scott & Todd Kreider,

    The data is clear that social distancing preceded the lockdowns, and continued (especially by the elderly) after they were lifted. However I think a lot of people were scared by the government’s response. If epidemiologists and the media had of been more truthful about the dangers from the virus, I believe the economic impact would have been lessened but still very substantial.

    In market news today, bankrupt companies keep getting bid up to the moon. Bankrupt HTZ was up 115% to a $787M market cap. CHK was up 182% to a $684M market cap, and right after market close Bloomberg reported they’d be filing chapter 11.

  29. Gravatar of Student Student
    8. June 2020 at 15:44

    Looks like we have decided to go the 1918 route and cross our fingers. Let’s hope we get lucky and we don’t get a second wave in the fall.

  30. Gravatar of ssumner ssumner
    8. June 2020 at 18:42

    Sean, You said:

    “I’ve moved closer to Trump since the protests. Never liked his rhetoric, but I understand it. I abhor identity politics.”

    Trump is all about identity politics. He’s a white nationalist.

    You said:

    “Best I can tell the country is united behind herd immunity now”

    Then why are cruise ships empty? Airlines? Hotels? Sports stadiums?

    Jay, No it isn’t. Testing is endogenous; it increases when cases increase.

    Grant, Here’s how I think of it. With lockdowns the airline industry falls 95%. With social distancing but no lockdowns it falls 85%. Either outcome is a really bad economy.

  31. Gravatar of Todd Kreider Todd Kreider
    8. June 2020 at 19:53

    “Grant, Here’s how I think of it. With lockdowns the airline industry falls 95%. With social distancing but no lockdowns it falls 85%. Either outcome is a really bad economy.”

    Which is absolutely delusional to claim such close outcomes. Then again, you are an economist and not a scientist so sort of understandable.

  32. Gravatar of rwperu34 rwperu34
    8. June 2020 at 20:01


    That is incorrect. We had a big surge in testing the first week in May. Since then testing has been flat. The positive % has climbed from 5% the week of May 10 to 12% the week of May 31.

    It also shows up in our Hospital Covid Specific Metrics. Every single one (inpatient, emergency, ICU, ventilators in use) is currently at or near an all time high that was set within the last three days.

    We were, in a very best interpretation, flat during the stay at home order. Since that was lifted, our outbreak has exploded.

  33. Gravatar of Todd Kreider Todd Kreider
    8. June 2020 at 20:03

    Don’t be so stubborn all the time. The Swedes have “Kurzarbeit” as well, they aren’t really working, but they don’t lose their jobs either. The government is paying most of their salary. Not to mention that half Sweden’s GDP comes from exports.”


    What am I being stubborn about? Scott said Sweden is in a depression without any data at all to back that claim up. When I pointed out that Sweden’s unemployment rate in April was the same as it was in January, Scott ignored that and said: “Let’s return to the issue in six months.”

    Well, OK, but “let’s return to the issue in six months” isn’t quite the same as showing Sweden is in a depression in early June, right?

  34. Gravatar of dtoh dtoh
    8. June 2020 at 21:26

    Here are a couple of thought provoking articles. Not the standard narrative but very smart people.

    The latter is in Japanese so here is a machine translation.

    Translation follows

    We asked Dr. Miyasaka of the Department of Immunology what is wrong with the commonly believed theory of herd immunity (1/2)
    Masato Kimura – International Journalist in the UK
    Sat, 16 May, 13:58

    The mathematical model of infectious diseases is based on population immunity theory. However, if the number of people infected with the new coronavirus and carrying antibodies increases to a certain extent, will these people become a barrier and the epidemic will really come to an end?

    We asked Professor Masayuki Miyasaka of the Frontier Research Center for Immunology at Osaka University, a leading expert in immunology who has become well known on television, via videophone.

    Kimura:On the 15th, Minister of Health, Labor and Welfare Katsunobu Kato revealed that the positive rate of antibodies against the new coronavirus was 0.6% in 500 blood samples donated in Tokyo and 0.4% in 500 samples donated in six prefectures in the Tohoku region.

    I hear that a large-scale antibody survey will be conducted next month, but what does it mean?

    Miyasaka: We haven’t made public which kit was used. Some antibody test kits have poor accuracy and sensitivity. The positive rate in this case came out quite low, and I think it’s difficult to interpret.

    A paper that came out recently looked at 14 different antibody testing kits and found that only three could be used satisfactorily. In other words, the antibody test kits are very poor in terms of accuracy and sensitivity at this stage. The kit that comes out with a high rate of positivity hooks up the nasal cold corona.

    The reason for the low positive rate is due to poor sensitivity and, in the case of the new coronavirus, due to very poor immunity. The antibodies don’t come up easily and the amount is low.

    Previous papers have looked at the formation of antibodies and the severity of the disease. If only good antibodies (good antibodies) were produced, then the rate of severe disease should not decrease as antibodies appear and increase.

    However, in many cases, the rate of severe disease is also increasing, even though the level of antibodies is increasing. On the other hand, it is people with mild illnesses who have low levels of antibodies.

    There are at least three types of antibodies. In SARS (Severe Acute Respiratory Syndrome) and MERS (Middle East Respiratory Syndrome), it has been reported that bad antibodies are produced along with good antibodies.

    In the case of HIV (human immunodeficiency virus), all the antibodies that can be produced are useless antibodies, and no matter how many antibodies are produced, they do not kill the virus.

    These unassisted antibodies are also produced in the new coronaviruses. Therefore, simply looking at the amount of antibodies, it is hard to know how much of the correct immunity is really developed.

    Mr. Miyasaka (Courtesy of him)
    Then there is a way to measure only the good antibodies.

    A neutralizing antibody assay is it. There is a test to determine how much the infection is suppressed if antibodies coexist in the cells when the virus is injected into cultured cells in a test tube, and the ability to neutralize the degree of virus infection.

    This measurement can only be made at Biosafety Level 3. It can only be done where you have cultured cells and the virus is being cultured. Normal laboratories cannot do this.

    Regular laboratories simply measure the amount of antibodies that bind to the virus. In the case of the new coronavirus, it is thought that all three types of antibodies may have been produced. That’s the problem with antibody testing kits.

    We only measure the amount of antibodies, not their function.

    In the case of HIV, even if antibodies can be produced, they are all useless antibodies, so a vaccine is not yet available. This can happen even with new coronaviruses.

    From what we have seen so far, the new coronavirus has a weak way of making antibodies and the timing is slow. It comes down to the question of whether it is OK to measure only antibodies.

    In terms of the PCR positive rate, it is less than 10% in Tokyo (author’s note: cumulative total is 9.5% in Tokyo and 6.9% in Japan).

    In Germany, where so many PCR tests are performed, the positive rate is about 6% (author’s note: 5.6%), which is about 6 out of 100 people. Considering this, there are probably a few more or less infected people in Tokyo as well.

    However, if you look at the antibodies, it could come out a little higher. This is because with the current antibody test kits, there is a possibility that the nasal cold corona may be trapped. Apparently, the numbers that come out don’t seem very credible.

    On the other hand, an antibody test kit recently released by Roche in Switzerland has a sensitivity of 99%. It’s also very accurate, so I think if you use something like that, you can see what percentage of people are infected in today’s society.

    The Pasteur Institute reports that only 4.4% of people were infected when they checked in France, and even in Paris, where the infection was most widespread, it was 9-10%. It was 5% in Spain as well, he said.

    There were questions about which antibody test kit was used and how sensitive it was, but the media was of the opinion that only a few percent of the patients were infected and that this virus does not build up collective immunity well.

    Apparently, this virus is very weak in its ability to cause immunity, and when it does, it’s slow. Looking only at antibodies, it is very difficult to judge.

    Until now, collective immunity has been judged only on the basis of the parameters of acquired immunity and also on the basis of antibodies, but I think this is wrong.

    The body’s defense against viruses is not defined only by acquired immunity, but also by our immunity, which is a two-stage system of innate and acquired immunity.

    If your natural immunity is strong, you may be able to fight off the virus even if your acquired immunity doesn’t work.

    Since natural immunity alone can sometimes fight off viruses, you may not be able to determine if you have collective immunity just by looking at the amount of antibodies or the positive rate. Maybe that’s what’s happening this time around.

    Kimura: I don’t know if it’s appropriate to compare humans to livestock, but the terrible thing is the lesson of foot-and-mouth disease.

    In the UK, 6.5 million livestock have been slaughtered in response to foot-and-mouth disease, based on a mathematical model of the new coronavirus, developed by Professor Neil Ferguson of Imperial College London.

    The foot-and-mouth disease virus has also mutated repeatedly, and the vaccine is not foolproof. Although the lethality of new coronaviruses is not as high, the economic, social, and political costs are immeasurable.

    It seems to me that we have to be prepared for a nightmare scenario.

    Miyasaka: The problem is the way we think about population immunity. This is a calculation of “what percentage of a particular population will be immunized to stop an infectious epidemic,” not an indication of what percentage of people will die if they are not immunized.

    That’s where I think it’s being used incorrectly.

    Assuming a basal reproduction number (Ro) of 2.5 in the new corona, the population immunity threshold is (1-1/2.5)x100 = 60%, suggesting that 60% of people need to retain immunity to stop the epidemic.

    It should be noted, however, that in this case, it is implicitly understood that “immunity” generally refers to the formation of antibodies and that it is “acquired immunity”.

    However, at the individual level, defense against viruses is a two-step process, and innate and acquired immunity are involved in viral exclusion.

    If innate immunity works well, even if a small number of virus particles invade, innate immunity alone may be able to eliminate the virus. This means that even if acquired immunity doesn’t work, the virus may be able to be eliminated.

    In fact, recent studies have shown that innate immunity can be trained and strengthened by a variety of stimuli.

    For example, it has been pointed out that BCG, a tuberculosis vaccine, not only increases immunity against tuberculosis bacteria, but also increases the ability to respond to common bacteria and viruses, suggesting that BCG strengthens and trains innate immunity as a mechanism of action.

    To illustrate this possibility, a Dutch research group is looking at the frequency of transient viremia that appears after BCG vaccination with the live yellow fever vaccine.

    BCG vaccination significantly reduced the incidence of viremia (without the involvement of acquired immunity), suggesting that trained and enhanced innate immunity can result in biological defense against viruses even in the absence of acquired immunity.

    In other words, when we talk about population immunity, we need to take into account both innate and acquired immunity working at the individual level, and not just acquired immunity.

    In the case of the new coronavirus, as mentioned above, it is believed that about 60% of people need to remain immune in order to stop an epidemic, but is that really the case?

    For example, in Wuhan City in Hubei Province, China, where there have been severe epidemics in the past, and on the cruise ship Diamond Princess, only about 20% of the people were infected. It has not been observed that as much as 60% of the population gets infected.

    The reason for this is that when a major epidemic begins, people begin to take quarantine measures and restrict contact, and with that, the basic reproduction number mentioned above decreases (this is called the effective reproduction number).

    If the R-value is lowered to 1.2 by contact restriction, the population immunity threshold is less than 20% (author’s note: 16.7%) according to the above formula. I suspect that this is what was actually happening in Wuhan City and the Diamond Princess.

    This means that while some people may have used both innate and acquired immunity to fight off the virus in the form of subclinical infection, a significant number of people may have used only innate immunity to fight off the virus.

    It is therefore possible that many people have fought off the virus before the infection was established.

    As more sensitive and accurate antibody measurement kits come out, we will be able to determine the validity of this idea when we can see what percentage of people really acquire antibodies (infected or not).

    Secondly, the idea of collective immunity has been used to support this idea: “Since we are not immune to this virus, if the infection spreads in an unprotected state, about 60% of the people in the population will be infected.

    In fact, Professor Ferguson in the UK, the Swedish epidemiologist Anders Tegener, and Professor Hiroshi Nishiura of Hokkaido University’s Graduate School of Medicine, the Ministry of Health, Labour and Welfare’s cluster countermeasures team, also cited these figures.

    However, I think this assumption is different. As mentioned above, this has not happened in Wuhan City or Diamond Princess. This hasn’t happened in Spain or Italy.

    In times of major infections, people always take strong traffic control measures, such as urban blockades, so that infections are suppressed and the number of effective reproductions goes down. They then settle for a much lower population immune threshold than expected.

    The immunity caused by this virus is not very high and seems to be short-lived, so from an immunologist’s point of view, a situation in which as much as 60% of the population becomes immune is unlikely to happen unless a very good vaccine comes out.

    There is no denying the possibility that they did not encounter the virus. But the virus spread even before the introduction of urban blockades and social distances.

    Nevertheless, we have not had a situation where 60% of the population would be infected if no measures were taken, as Professors Ferguson and Nishiura have said.

    I believe that Professor Nishiura’s theory itself is correct, but the assumption that 60% of the population will be infected by this virus and hundreds of thousands of people may die if no countermeasures are taken is wrong.

    I don’t know which is right, but when a good antibody test kit comes out we’ll find out if only 20% of the people really got infected.

  35. Gravatar of Jens Jens
    8. June 2020 at 22:42



    In Germany, where so many PCR tests are performed, the positive rate is about 6% (author’s note: 5.6%), which is about 6 out of 100 people.


    Just a current footnote: The positive rate is published every Wednesday in Germany. The last number, from 06/04/2020 for calendar week 22, is 1.0%. (a bit further down)

    The only rational way to deal with the current uncertainty is clear communication about what is known, what is unknown and what changed.

  36. Gravatar of Postkey Postkey
    8. June 2020 at 23:28

    “Postkey, Yes, but of course China had far more draconian policies than other countries.”

    Beijing’s ‘lockdown’ started on the 25-6th March.

    “1st known case of coronavirus traced back to November in China”.

    This is about 3 months before the introduction of ‘draconian policies’?

    Still only 9 deaths!

  37. Gravatar of Benjamin Cole Benjamin Cole
    9. June 2020 at 02:15

    Scott Sumner, and many others, call President Trump a “white nationalist.”

    Fair enough.

    But no one ever calls Xi Jinping a “yellow nationalist.”

    Why the difference? Just PC-ism?

  38. Gravatar of Postkey Postkey
    9. June 2020 at 02:21

    “A new study from Harvard Medical School led by Dr John Brownstein analysed commercial satellite imagery.
    His team ‘observed a dramatic increase in hospital traffic outside five major Wuhan hospitals beginning late summer and early fall 2019’.”

  39. Gravatar of Justin Justin
    9. June 2020 at 06:49

    “@Jason: Covid is far more transmissible inside (churches) than outside (protests)

    @Jason: Also, Covid is far more dangerous for old people (churches) than young ones (protests)”

    Yes, but:

    – Churches can do social distancing in an orderly fashion, with people in every other pew quietly praying and wearing masks. I say this from personal experience.

    – The protesters/rioters are in close quarters for extended periods and are spending much of their time screaming/shouting – which from what I’ve heard is the primary transmission mechanism for COVID.

    – One of the reasons for the lock downs was that younger/healthier people who had mild to no symptoms would spread it to others (parents, grandparents, others with risk factors), so it’s no good to say that protesters tend to be young, unless you think they are going to quarantine themselves for 2 weeks after.

    – The media was screaming about how the protests against the lock down was going to create a huge surge of COVID cases.

  40. Gravatar of Christian List Christian List
    9. June 2020 at 07:10

    I just wrote that they expect GDP to shrink 7% in 2020. It is not reflected in the unemployment figures because the Swedes have a lot of short-time work, just like Germany. They are in a recession right now. And they are not doing better than their neighbors economically. How could they, 50% of their economy is based on exports.

    Keep in mind that it is the “strategy” of the Swedish chief epidemiologist to be prepared against the virus in the long run. He wants to be better than the other countries in the long run, so he says that if (a certain amount of) people gets sick now, Sweden will do better in the long run. There’s no proof for this theory. The usual strategy is just not getting sick and not dying at all.

  41. Gravatar of msgkings msgkings
    9. June 2020 at 07:38


    We know a lot more about the virus now. Transmission is hard outside. The WHO just said asymptomatic people don’t transmit the virus very often. Old people know to stay isolated, especially from their relatives who might be out protesting. More of the Floyd protestors wear masks than the lockdown protestors did.

    And finally, if the lockdown protests were fine, then these surely are too.

    Bottom line, protests (outside, with mostly young people) are probably not a big deal no matter which ‘team’ is out there protesting.

  42. Gravatar of ssumner ssumner
    9. June 2020 at 08:03

    Todd, OK, the same sort of depression as the US and Denmark, in terms of output.

    doth, He make some good points.

    Ben, Xi is a Han nationalist. It has nothing to do with “yellow”. (SMH)

  43. Gravatar of Christian List Christian List
    9. June 2020 at 09:34


    Maybe it is better to keep the churches closed for another 2-3 years. I saw this funny graphic on reddit, a timeline on the x-axis with the date when the pope announced that he would pray that the sickness would go away. The cases exploded exponentially after the pope’s announcement.

    Ben, Xi is a Han nationalist. It has nothing to do with “yellow”.


    that’s true, but Caucasians don’t have white skin color either, most blacks don’t have black skin color, and Indians don’t have red skin. Yellow is the color that was still available, I guess. To me Chinese/Japanese/Koreans are white, I don’t see any differences in skin color. I think you wouldn’t see (huge) differences in bone structur either if you were to examine morphologically the skeleton only, but I’m not sure.

  44. Gravatar of Brian Donohue Brian Donohue
    9. June 2020 at 10:58

    @dtoh, excellent link. The idea that a substantial proportion of the population has “natural immunity” to the virus makes a lot of otherwise conflicting data fall into place.

  45. Gravatar of Christian List Christian List
    9. June 2020 at 12:57


    The idea that a substantial proportion of the population has “natural immunity” to the virus makes a lot of otherwise conflicting data fall into place.

    This reminds me of “dark matter” and “dark energy” in physics. When the data is complicated and contradictory, the human brain starts inventing shit just to make the data fall into place. That’s a bit vulgarly put, but it’s kind of my impression, in this case and in physics.

  46. Gravatar of Tom Tom
    9. June 2020 at 16:39

    Just a note, people definitely go indoors during the summer in AZ but it’s interesting to see how many people just shift their outdoor activity to the early morning.

  47. Gravatar of JayT JayT
    9. June 2020 at 19:52

    @rwperu34, I don’t know where you are getting your data from, but I’m using this site:

    And according to that, the beginning of May didn’t have some large increase in testing that has since been flat. They averaged 2,870 tests per day the last seven days of April, and 3,430 tests per day in the first seven days of May. That’s compared to 9,245 tests per day the first seven days of June.

    Also, I still disagree that the reopening has lead to an “explosion” in cases. In the 19 days since Arizona started reopening, there have been
    12,948 new cases
    140,107 tests
    for a rate of 8.9%

    In the 19 days leading up to that, there were
    6,984 new cases
    84,224 tests
    for a rate of 8.4%

    I’d believe that reopening has lead to an uptick in cases, but I stand by my assertion that most of the new cases are accounted for by increased testing, unless you haver more reliable data.

    @Scott, testing is endogenous when there are enough tests to go around to test anyone showing symptoms. Unless Arizona was unaffected by the shortages the rest of the country saw, I don’t think this explains it away.

  48. Gravatar of ssumner ssumner
    9. June 2020 at 20:58

    Jay, When you exogenously increase testing, the positive rate should fall sharply.

  49. Gravatar of rwperu34 rwperu34
    9. June 2020 at 21:51


    I’m pretty sure Covid tracking is reporting numbers when they are reported. The AZDHS website I’m pretty sure is reporting when the test was taken (although I can never be sure!). Under laboratory testing, you can see the PCR tests, week of;

    May 3, 36,266 (5%)
    May 10, 45,055 (5%)
    May 17, 37,168 (6%)
    May 24, 42,679 (9%)
    May 31, 41,151 (12%)
    Results from the last 4-7 days may not be reported yet.

    You can also see the rise in our Hospital “COVID-19 Specific Metrics”. Within that section there are tabs for inpatient, ICU…etc.

    The rising trend isn’t quite as clear in “Hospital Bed Usage and Availability”, but it’s also clear that it was never falling. This particular metric is not Covid specific and beware the changing denominator.

    Lastly check “Hospital COVID-like & Influenza-like illness Surveillance”. This is the main one the Governor has been using to show that we were heading in the right direction. Again, beware the changing denominator. While it’s true that this one had been on a downward trend until the last couple of weeks, I read this number of Covid divided by number of total hospital admissions. If so, it should be noted we started to allow elective surgery on May 1.

  50. Gravatar of James Alexander James Alexander
    9. June 2020 at 21:59

    Swedish economy is in trouble right now. Official lockdown or no.

  51. Gravatar of ssumner ssumner
    10. June 2020 at 13:28

    James, Yes, Sweden’s recession will be similar to the other Nordic countries—quite deep.

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