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The Misunderstood Theory of Herd Immunity

sheep

The herd can be protected by vaccinating enough of the sheep?

Because of the recent outbreaks of measles in the United States and the re-energized public debate about vaccines and vaccination policy, we’re again starting to hear references to the theory of “herd immunity.” The theory is the foundation for the mass vaccination campaigns around the world. It currently stipulates that in order to provide immunity to a population against contagious diseases like measles you must vaccinate at least 95% of the population. Theoretically-speaking, with a vaccination rate of 95%, the diseases should be eradicated.

In an epidemiological review paper titled “Herd Immunity: History, Theory, Practice,” written by Paul E. M. Fine and published in 1993, the author notes that the first “published use” of the term herd immunity “appears to have been” in a paper titled “The spread of bacterial infection: the problem of herd immunity,” written by W. W. C. Topley and G. S. Wilson and published in 1923. From Fine’s paper, it seems that the theory of herd immunity was originally developed based on some observations with mice and some “simple mathematical formulations,” but the paper is unclear about whether the theory was ever validated through some of sort scientific peer review process—as is commonly the case with theories that eventually come to be widely accepted as “proven science.”1 2

In 1933, Dr. Arthur W. Hedrich, a health officer in Chicago, IL observed that during 1900-1930, outbreaks of measles in Boston, MA appeared to be suppressed when 68% of the children contracted the virus.3 Subsequently in the 1930s, Dr. Hedrich observed that after 55% of the child population of Baltimore, MD acquired measles, the rest of the population appeared to be protected. It was that observation that formed the basis for mass vaccination campaigns.4

When the mass vaccination campaign for measles in the U.S. began in earnest in the mid-1960s, the U.S. Public Health Service planned to vaccinate over 55% (based on the Baltimore observation) of the U.S. population, and it announced that it fully expected to eradicate measles by 1967. When that didn’t happen, the Public Health Service came up with vaccination rate figures of 70-75% as the way to ensure herd immunity. When eradication was still not achieved at those rates, public health officials jacked up the rates to 80%, 83%, 85%, and ultimately to 90%.5

The process by which the decisions to raise the rates is unclear. Was it based on some scientific methodology or assumptions? Or were the decisions simply made because officials felt pressure to fulfill their promises to fully eradicate measles? Did they ever consider pausing and re-evaluating the original premise behind the theory of herd immunity? Or did they trudge on, arbitrarily raising the bar?

Now the rate is up to 95% to achieve herd immunity. But as we see with the continual outbreaks, even at 95% we still do not have full immunity. In China, the vaccination rates are even higher—99%. But there are also still measles outbreaks there.6 So is the answer 100%? And what if at 100% you still get outbreaks? We’ve gone from herd immunity supposedly achieved at 55% to herd immunity that is clearly not achieved even at 95%. At what point will public health officials have to confront the possibility that herd immunity may not be the best theory on which to base vaccination policy?

The population of the U.S. stood at about 318.9 million in 2014.7 The “baby boomer” generation (those born between 1946 and 1964) account for about 24% of the total population.8 Many years ago, it was believed that childhood vaccines lasted a lifetime. It was not until relatively recently that it was discovered that most of these vaccines lost their effectiveness 2-10 years after being given.9

Thus, for at least the past 40 years, the one-quarter to nearly 40% of the U.S. population represented by the baby boomers has had no vaccine-induced immunity against any of these diseases for which they had been vaccinated as a child. If you include those born after 1964, the percentage of the unprotected surpasses 50%. According to retired neurosurgeon Dr. Russell Blaylock, “If we listened to present-day wisdom, we are all at risk of resurgent massive epidemics should the vaccination rate fall below 95%.”9

Given that at least half the population has effectively been without vaccine protection for many years, we should have experienced a massive resurgence in childhood infectious diseases. But this has not happened. In other words, we haven’t had herd immunity in the U.S., and yet the world hasn’t come tumbling down.


Note: For the Spanish translation of this article, see “La Incomprendida Teoría de la Inmunidad de Grupo” in Argentina sin Vacunas.

References:

1 Fine PEM. Herd Immunity: History, Theory, Practice. The Johns Hopkins University School of Hygiene and Public Health. Epidemiological Reviews 1993;15(4):265-302.
2 Topley WWC, Wilson GS. The Spread of Bacterial Infection. The Problem of Herd-Immunity. Journ. of Hyg. xxi: 243-249.
3 Hedrich AW. Estimates of the child population susceptible to measles, 1900-1930. Am. J. Hyg. 17:613-630.
4 Oxford Journals. Monthly Estimates of the Child Population “Susceptible” to Measles, 1900-1931. Baltimore, MD. Am. J. Epidemiol. 17(3):613-636.
5 Solomon L. Junk Science Week: Vaccinating the ‘herd’. National Post June 19, 2014.
6 Ji S. Why Is China Having Measles Outbreaks When 99% Are Vaccinated?. GreenMedInfo.com Sept. 20, 2014.
7 United States Population. Trading Economics N.d.
8 Pollard K. and Scommegna P. Just How Many Baby Boomers Are There?. Population Reference Bureau N.d.
9 Blaylock R. The Deadly Impossibility Of Herd Immunity Through Vaccination. International Medical Council on Vaccination Feb. 18, 2012.

29 Responses to The Misunderstood Theory of Herd Immunity

  1. Paul Thomas MD Reply

    June 23, 2015 at 8:14 am

    Herd immunity is being used as an absolute in this article and I think the reality is lost when you think of it as all or none.
    With the measles example – this is one disease that is no longer endemic (meaning transmitted year to year within the population) and the vaccine (herd immunity) in the US has worked for that disease. Does that mean there will be no cases of measles – no, there will, as we witnessed the past couple years – but it doesn’t take hold in the population because enough of us have lasting immunity.
    The measles vaccine is a live virus, I draw measles titers on all my patients years after only one vaccine and about 95% have very high titers still – in other words – this vaccine gives lasting immunity. I suspect that is because the live virus is still alive and well in our bodies triggering ongoing surveillance (antibodies).
    I suspect for measles one could claim herd immunity at various levels of vaccination – be it 70%, 80%, or 95% and yes at 100% there will be vaccine failures and thus some will still get measles – but that doesn’t mean we don’t have herd immunity. In Oregon, this past year, the one man, 40 year old, who got measles from the Dysneyland “epidemic” did not pass it to anyone! I would say that vaccination worked.
    Having said this – don’t mistake my comment to mean I want every kid to get this vaccine at age 12 – 15 months. I suspect this one is so powerful that it should be delayed at least until age 3 years and not given to many in the population who are at risk of vaccine injury.
    As for non-live virus vaccines – take DTaP – this one will never give herd immunity as it doesn’t give lasting protection, and the article is right ON! No amount of vaccination will achieve the desired herd immunity no mater what % you place it at since it doesn’t give lasting protection.
    Thank-you for the article, very nicely done and important history. I get crazy when I read of recommended percentages needed for herd immunity. It is relative and as pointed out, it doesn’t work in most cases. The live virus vaccines being the likely exception (MMR, varicella) as those viruses likely stay alive in our bodies and are thus continuously stimulating us to make the antibodies. Example shingles – can happen decades after either the chicken pox infection or the vaccine. That virus was alive and well in our nerve roots for decades – suppressed by our immune system until perhaps our immune system takes a hit or wanes in old age.

    • Lorena Gaertner Reply

      June 23, 2015 at 9:49 am

      Nice!
      One do not happen to read many doctors expressing their opinion in such a neutral way!
      I’m glad there are still out there professionals untouched by hysteria and prepotensy.
      I’m quoting you.

      “I suspect this one is so powerful that it should be delayed at least until age 3 years and not given to many in the population who are at risk of vaccine injury.
      As for non-live virus vaccines – take DTaP – this one will never give herd immunity as it doesn’t give lasting protection, and the article is right ON! No amount of vaccination will achieve the desired herd immunity no mater what % you place it at since it doesn’t give lasting protection.”

      Recently, a mom lost her infant due to “SIDS” (aka killed by vaccines) the mom said at the autopsy report her daughter did not show any virus in her body. She meant to say that apparently, the daughter acquired zero immunization after all.

      • Lowell Reply

        December 3, 2015 at 3:48 pm

        Here is the problem, and as quoted directly from Paul Thomas’s post. What effect does this have in regard to human health? This is not a natural form of immunity.

        [The measles vaccine is a live virus, I draw measles titers on all my patients years after only one vaccine and about 95% have very high titers still – in other words – this vaccine gives lasting immunity. I suspect that is because the live virus is still alive and well in our bodies triggering ongoing surveillance (antibodies).]

        There are clearly benefits in regard to acquiring natural immunity to measles. That remains true, and regardless of how many fake and junk science studies vested interests in vaccines sources, put forth showing just the opposite. They keep creating such studies falsely attempting to create an illusion that vaccines can do what natural immunity does. That conclusion and in its promotion, is nothing but major fraud.

        The truth about the measles, natural immunity, and the vaccine
        http://www.vacfacts.info/the-truth-about-the-measles-natural-immunity-and-the-vaccine.html

        The truth is that measles vaccine clearly does not provide immunity, for life. We have millions of adults which obviously to not have any remaining immunity to measles, and after decades of not being re-vaccinated since childhood. How do they explain that, and not this resulting in an epidemic of measles? That is vaccine derived herd immunity really exists and does what they claim it does?

        The False Theory of Vaccine Derived – Herd Immunity
        http://www.vacfacts.info/the-false-theory-of-vaccine-derived—herd-immunity.html

    • Leslie Manookian Reply

      June 23, 2015 at 10:42 am

      You mentioned using titers to check for “lasting immunity” after measles vaccine but the presence of antibodies does not mean a person is immune. It is now understood that one can have antibodies and NOT be immune and conversely one can be immune withOUT antibodies. Immunity is far more complex than titers and one must question the whole premise of vaccination given this knowledge.

    • beverly gardner Reply

      June 23, 2015 at 8:47 pm

      As an RN working in a family practice for several years, 2003-2009, we saw hundreds of cases of shingles in all ages of people. I am not an epidemiologist or a scientist, but it makes sense to me if we (baby boomers) are not exposed to the wild virus of chicken pox, the already dormant virus from our childhood infection of chicken pox needs a reminder. With the introduction of the varicella vaccine, chicken pox cases have dropped but shingles cases have increased seemingly 10 fold. Sometimes I feel it is best left to mother nature. Let the virus stay in society to better serve the health of the “herd”. I personally witnessed severe cases of shingles which caused blindness, and life long herpetic neuralgia. Now the multi billion dollar pharmaceutical industry creates the shingles vaccine but only available to people over the age of 65.

      • Stephanie S. Reply

        June 25, 2015 at 4:33 pm

        Beverly,

        You are absolutely correct that all of us are at greater risk of shingles in our senior years because we need to be around children who have recently had the chicken pox virus in order to protect us from shingles. With Varicella vaccination today, we as seniors will not have contact with children who’ve had the chicken pox, thus increasing the chance we will get shingles. But of course, Big Pharma thought this one through because surprise, surprise, they have a shingles vaccine! Lots of articles on this topic of shingles rates increasing with varicella vaccination rates increasing on Pubmed.com. Here is one interesting article discussing this. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2374947/

    • David Eade, DC Reply

      June 27, 2015 at 2:58 pm

      Hi Paul: Wow, that was an insightful comment. No sarcasm. However, after having dealt with Dr. Pan in California, and other MD.s they show little to no knowledge of vaccines. However, the example of herd immunity is primarily used with more efficacy in patients who acquired the live “wild” virus as this keep the titers high but most importantly these patients do not get measles again. During the Disneyland outbreak patients who had been up to date on Measles vaccine were re-inoculated with the “wild” strain and caught measles. The observation here is the following, if Measles titer is high enough then the vaccine is not effective as we thought for preventing measles. Current realities such as the information of “Gross Negligence” and “falsified reporting” which are from Very Reputable sources i.e Dr. Thompson senior scientist at the CDC, who admitted to falsifying data with his colleagues regarding outcomes and rates of autism amongst African Americans. Then there is the data that was completely fabricated as reported by the Senior Scientist for GSK and how they were forced to fabricate data on the mumps vaccines. So while the “Herd” immunity is used by the vaccinated population it’s origin is from “naturally’ infected individuals and the correlation to non-vaccinated is becoming more and more obscured due to “GROSS” AND DELIBERATE” misconduct by the pharmaceutical manufacturers. The problem this has is that science no longer bears scrutiny. One cannot ask question against a vaccine to determine it’s efficacy or if it works we are “commanded” to trust all vaccines for their effectiveness as deemed by “Governing” bodies of medicine. That is the problem. I do appreciate your thoroughness and wish that my patients had a physician to talk to like you who is engaged in their health and will run titers on patients. I commend you. My next request is to please look at the data “objectively” and perhaps a bit skeptically as the MMR studies are flawed. Thanks

    • Crystalyn Reply

      August 20, 2015 at 9:31 pm

      I have to say that the MMR vaccine isn’t always effective, especially in just 1 dose, for measles. My mother got the MMR when she was young, then a tornado destroyed the hospital records, so she got a second one for school. Then when she got pregnant with me, they ran a titer and found she was not immune, so she got it again. Then they ran the titer when she was pregnant with my brother, and again (just 2 years later) she was not immune. And again 12 years later, the 5th vaccine was given since the titer again came out negative. (She still isn’t “immune”) She may be the exception to the rule, but it paints a pretty lousy picture for the measles vaccine. In the US measles is miserable, but no one has died in many many years. It would have been better for her just to have gotten the REAL immunity from being miserable for 2 weeks and catching the measles virus.

    • Lowell Reply

      September 21, 2015 at 8:54 pm

      Then why are there all these outbreaks where there exist 80 to 90% that have been vaccinated, and many fully vaccinated and on schedule? and it those said antibody titer’s as you say, remain so high? Obviously there far more to vaccination, immunity, and so called immunization, than just the measured existence of antibody titers.

      The Current Failure of Pertussis and Measles Vaccine
      http://www.vacfacts.info/the-current-failure-of-pertussis-and-measles-vaccine.html

      The truth about the measles, natural immunity, and the vaccine
      http://www.vacfacts.info/the-truth-about-the-measles-natural-immunity-and-the-vaccine.html

    • JC Reply

      November 7, 2015 at 12:05 pm

      We also need to realize that there are still many adults alive today who have natural immunity to measles as we had them as kids, so how will that tip the scale as the older naturally immune pass away.

    • Valerie Borek, Esq. Reply

      November 11, 2015 at 8:13 am

      Dr. Thomas thank you for your comments. I do appreciate your ability to think critically wrt vaccines, and your perspective on “epidemics.” I must point out though, a logical leap:

      “In Oregon, this past year, the one man, 40 year old, who got measles from the Dysneyland “epidemic” did not pass it to anyone! I would say that vaccination worked.”

      There are many possibilities for why the disease did not transmit from this one individual you mention. I hadn’t heard of him so perhaps more info? What exposure did people have to him? (Was he self-quarantined? Did he seek medical attention at a hospital or private physician office?)

      After exposure, assuming people don’t catch a disease because they are vaccinated ignores the possibility of natural immunity from previous exposure or the possibility that an immune system is strong enough to fight off the disease without showing symptoms that would prompt a person to go to a drs office (and thus be reported and counted as a case of the disease). I’d say given what we know about vaccine failure/waning immunity, and about vaccination/booster rates in OR & west coast in general, that it cannot be safely assumed that vaccination alone stopped the spread of measles from this one individual.

  2. Natalie Costa Reply

    June 23, 2015 at 9:19 am

    I find it interesting that the doctor said that after 1 vaccination many years later his patients have a 95% immunity after ONE vaccine. This is pretty incredible data since the children receive 2 doses before age 2 and 4 more shots when they reach the 7th grade. Something is wrong here. Either the CDC and pharma are over vaccinating our kids for money (imagine that) or the good doctor has just opened a can of worms in the fight against forced and over vaccinations. When children enter middle school in California they are required to get 4 more boosters of the MMR. The OC health department told me that “the immunity wears off”. What’s the truth? 56-60 shots in a child’s lifetime before they become tweens. Could the medical mafia be real?

    • Terri Reply

      June 23, 2015 at 9:37 am

      Natalie, immunity depends greatly on the age the vaccine is given. A vaccine given after 2 years old is likely to be much more effective than anything given before 1 years old because the baby’s immune system is not developed yet. If you look at the medical literature, the catchup schedule frequently involves only one or two doses after age 4.

  3. kathryn Reply

    June 23, 2015 at 10:03 am

    The repeat vaccines are about training the moms to bring in the kids. There have been honest doctors who have admitted that.

  4. Joyce Kinsey Reply

    June 23, 2015 at 10:22 am

    I think the real question is: Does vaccination cause more harm than the disease itself?
    In the case of smallpox, once the disease was declared eradicated by the WHO, the consensus was that the incidence of adverse reactions to the vaccine was greater than the incidence of infections by the naturally occurring virus. Thus, we no longer routinely vaccinate our children against smallpox.

  5. Stephanie Reply

    June 23, 2015 at 10:23 am

    Am I understanding correctly that the history of herd immunity was proven to be “real” and/or “effective” when it was naturally occurring? In the examples given, they imply that no vaccinations were introduced, but these children were naturally being exposed to the viruses, and when a majority percentage (such as 55%) was exposed, the spread stopped. I find this incredibly important! Nature is demonstrating it’s own ability to inoculate. This is perhaps why proving that polio vaccines successfully eradicated polio is hard to do, despite what history “says” happened. What if, as a lot of records show, polio was already on its way out due to this naturally occurring herd immunity? Help me out here.

    • SuzieHomemaker Reply

      June 24, 2015 at 11:40 am

      DDT was a lot of polio cases!! not polio. so the numbers went down because things were reclassified. it still is out there today. they just call it sometime else to cover that the vac does not work.

  6. Gary Cohen Reply

    June 23, 2015 at 12:31 pm

    “In 1933, Dr. Arthur W. Hedrich, a health officer in Chicago, IL, observed that during 1900-1930, outbreaks of measles in Boston, MA appeared to be suppressed when 68% of the children contracted the virus. Subsequently in the 1930s, Dr. Hedrich observed that after 55% of the child population of Baltimore, MD acquired measles, the rest of the population appeared to be protected. It was that observation that formed the basis for mass vaccination campaigns.”

    The first thing I think of when I read this paragraph is that some people have stronger immune systems than others. After all those whose immune system is weak catch the disease, the disease stops spreading. It has nothing to do with this ridiculous concept of “herd immunity.”

    By the way, in the wild do herds experience “herd immunity,” or is it just the human sheep that are supposed to require artificial intervention via vaccinations? Normally, among mammals, of which we humans are a part, the mother transmits her immunity to her offspring during normal, vaginal childbirth. After birth the infant gets more immune factors from mother’s milk.

    And in response to the comment of Paul Thomas, MD, the theory of herd immunity requires that everyone who gets the vaccine is no longer capable of transmission of the disease to others. In other words, all models have certain conditions, and frequently some unstated assumptions. If even one of those conditions are not met, the model no longer applies. For live vaccines, the transmission of the virus to those not vaccinated is well known, so the model fails. Under those circumstances, it should have surprised no one that the percentage vaccination for herd immunity to apply has been raised constantly. Einstein once said that insanity is doing the same thing again and again, and expecting a different result. Using a false model again and again and expecting it to work is either insane or stupid.

  7. Gary Cohen Reply

    June 23, 2015 at 12:46 pm

    To add to my previous comment, for non-live vaccines the immunity wears off, so obviously the herd immunity model fails there too.

    The comment by Leslie Manookian is well taken. I have also read that when a vaccine up regulates the production of antibodies, it can down regulate the other parts of the immune system.

    Of course, we all know that there is absolute no evidence that having multiple vaccines early in life either extends life, or reduces the total amount of disease during one’s lifetime. The whole thing is one big biology experiment in violation of the Nuremberg Code against forced human experimentation.

  8. Melissa Reply

    June 23, 2015 at 12:54 pm

    The first time I learned about herd immunity was in grade school when I learned about how the Native Americans were infected by diseases that the Europeans brought over. The Europeans weren’t dying from the diseases because of herd immunity, which the Native American populations had not yet acquired.

    So by giving immunizations that give us temporary immunity, are we wiping out our herd immunity? Do antibodies from vaccinated moms go through breastmilk to help their babies not die from diseases should they go around before the child gets immunized? Are we going to get to the point that instead of a mild childhood disease like chicken pox, we now have deadly diseases because we lost our true herd immunity?

    I wonder about this because I had rubella as a child. Through the years I had titers done with pregnancies and we could see my immunity gradually fade away. My mother also had it as a child and lost her immunity at the same time I did. Is this because we were no longer exposed to it because of vaccinations? If it’s just something that wears off over time, shouldn’t we have lost our immunity at the same age rather than at the same time?

    I just wonder if by trying to eradicate disease, we may be setting our children or grandchildren or great grandchildren up for big trouble. Has anyone more educated than I done any research on this?

    • Carol-Ann Reply

      October 23, 2015 at 7:05 am

      Great questions, Melissa. I recommend you look up some articles written by Dr Tetyana Obukhanych, Ph.D, an immunologist who has a lot to say on this very subject. I took an online course with her on and it really helped deepen my understanding.

  9. Gary Cohen Reply

    June 23, 2015 at 12:59 pm

    And one more point to add to my previous two comments. I believe that the “herd immunity” model also fails for the simple reason that vaccinations are not 100% effective. So it is obvious that even if 100% of the world’s population was vaccinated against a specific disease, you could still get it if it existed in the wild in another species in a similar enough form that it could be transmitted to humans. Have we already forgotten about the “bird flu” and the “swine flu” scare mongering?

  10. Gary Cohen Reply

    June 23, 2015 at 1:10 pm

    Melissa wrote: “The first time I learned about herd immunity was in grade school when I learned about how the Native Americans were infected by diseases that the Europeans brought over. The Europeans weren’t dying from the diseases because of herd immunity, which the Native American populations had not yet acquired.”

    Thinking about this I have to wonder if what you were taught is fact or factoid. Did the Native Americans die because they didn’t have herd immunity, or was it because the American settlers destroyed the health, and immunity, of the natives by depriving them of their native diet? Read the Weston A. Price, DDS, book “Nutrition and Physical Degeneration.” The so-called primitive diet of natives all around the world has both giving them excellent teeth, and freedom from most of the diseases we get.

    As far as the Europeans not dying from the diseases because of herd immunity, they obviously did not acquire herd immunity from Big Pharma’s vaccines! As I said before, your immunity should come from your mother, but also from acquiring the disease naturally as a child.

  11. curtis Reply

    June 23, 2015 at 4:32 pm

    Vaccines are a scam so please don’t insult my intelligence being a natural health practitioner for decades !

  12. Nan Reply

    June 23, 2015 at 5:43 pm

    I read once that the second MMR vaccine was given at the time of grade school, because it was estimated that 5% that had the shot before- usually between 12 and 15 months, were not immune, in other words the vaccine didn’t work in 5%, so the decision was made to just re-vaccinate the other 95% again. How sick is that?

  13. Jim Reply

    June 25, 2015 at 11:34 pm

    The myth of “Herd Immunity” thrives on herd mentality.

  14. Vicky Reply

    August 20, 2015 at 9:25 am

    I don’t know if this was mentioned but in reading the article the baby boomer generation ends in 1964 according to the article but the measles vaccination wasn’t really used until the 60’s so that leads a large number who probably had the measles naturally. The hard thing to know is how many have had the measles naturally after the vaccine became the norm. We will definitely see a resurgence I am sure but probably not for another decade or so when the majority of the baby boomers are gone. While they said they only make up 24% of the population it makes me wonder how many of their own kids have immunity carried on from their parents. We had less dna mutations in that first group of vaccinated kids. I think the real issue is going to be how bad will these diseases come back in the corrupted dna of these multi vaccinated generations.

  15. Krishna Murphy Reply

    September 13, 2015 at 6:51 am

    Vaccines are supposedly intended to prevent disease, or at least to ameliorate the effect of a disease when one becomes infected. But the truth of the immune system is that there are two parts to it – the innate (“non-specific” or “in-born” part) and the adaptive (“specific” or “acquired” or “learned” part.)

    Each of these has also got “humoral” and “cell-mediated” components, but that’s not really germane here. The bottom line is that the INNATE immunity constitutes about 98% of the overall function, and no matter how great a job “immunization” (in the truest sense) does of “teaching” the “learned” part, if it damages the innate part as much as current vaccines do then there’s no hope of any overall benefit, either to the individual or to the community.

    China has achieved over 99% uptake of a number of vaccines, and they REGULARLY have “outbreaks” of those same diseases amongst the “herd.” It just does NOT work the way the pharmaceutical companies tell us it does!

  16. Dorota Brodala Reply

    October 10, 2015 at 12:34 pm

    I’d like to see the reference list for this article and all the academic sources.

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