…Then How Are Unvaccinated Children a Danger?

I still can’t believe I’m writing this.

Last time, which was sadly much longer ago than I intended, I was writing about whether or not vaccines work. Which, of course, they do. Every disease we have a vaccine for has seen the rate of infection (and the death rate) decline by several orders of magnitude since the vaccine was introduced. Really, this isn’t even a discussion we should be having anymore.

Except that we still have memes—like the one above—floating around. Because we still have people deliberately pushing an anti-science agenda, who are trying to put their mad ideology above human life. Why? I genuinely don’t understand. But rather than dwell on that, let’s move to the other half of that meme:

“How are unvaccinated children a danger to vaccinated children?”

“Old fool! Why, there is a large patch in the hollow of his left breast as bare as a snail out of its shell!”

That’s a quote from The Hobbit—specifically, the scene where Smaug the dragon is boasting about how he is utterly indestructible. “Your information is antiquated,” Smaug declares. “I am armored above and below with iron scales and hard gems. No blade can pierce me.” But Bilbo Baggins, with his keen eyes, spots a weakness: an unarmored patch on his chest, leaving him open and vulnerable.

Uhm. Wait, what? I thought we were talking about vaccines?

We are. Really.

See, there’s a thing called community immunity, more often referred to as “herd immunity.” And, as you might imagine from the name, it is the ability of the community as a whole to defend itself from infection in the same way that a herd of animals protects itself from predators. Having enough tough, strong members can help the herd fight off the predators and keep most of the group alive.

Here’s how it works, in a nutshell: diseases are caused by living things (generally bacteria or viruses, though there some debate about whether viruses are “really” alive). Human diseases use humans as a breeding ground and food source, and they need humans to pass the disease organisms on to other hosts before our immune system kills them completely or they kill us (limiting their ability to be transmitted). In order to maximize their chances of survival, the infecting organism needs to balance out how long it lives, how easily it can come into contact with other hosts, and how likely it is to infect another host.

Smart people who study this kind of thing have come up with a figure called the Basic Reproductive Rate (referred to as R0), which is the average number of people an infected individual will subsequently infect as s/he comes into contact with them over the life of the infection. If R0 is greater than 1, it will continue to spread; if it is less than 1 it will burn out. And if R0 = 1? Then the rate of disease remains constant in the community.

If you want to see how R0 is calculated, let me refer you to “Notes On R0” by James Holland Jones, available on the website of Stanford University. But here’s the R0 for some of the disease we vaccinate against:

  • Diphtheria: 5–7 people
  • Measles: 12–18 people
  • Mumps: 4–7 people
  • Pertussis: 12–17 people
  • Polio: 5–7 people
  • Rubella: 6–7 people
  • Smallpox: 5–7 people
  • Chickenpox: 7–10 people

So, where does herd immunity fit into this?

R0 assumes that there is nobody immune in the population. Herd immunity is an actual rate that can be calculated from R0, indicating the minimum percentage of the population that needs to be immune to a disease to reduce R0 to less than 1 (because we don’t want a constant level of sick people). Those figures are generally estimated as follows:

  • Diphtheria: 85%
  • Measles: 83–94%
  • Mumps: 75–86%
  • Pertussis: 92–94%
  • Polio: 80–86%
  • Rubella: 83–85%
  • Smallpox: 80–85%
  • Chickenpox: I didn’t actually find a herd immunity level for this, but a rough calculation shows 86–91%.

Now, the herd immunity level will never reach 100% (sadly). Some people simply can’t get vaccinated for legitimate medical reasons—most commonly an allergy to some component of the vaccine, or they’re too young, or they have some medical condition that interacts poorly with the vaccine (such as an immunodeficiency, or pregnancy). Other people might get a bad batch that doesn’t work, or it simply might not take. Nothing’s perfect, after all. The problem is, herd immunity has a fairly narrow range for a population. Dip below 83% immunity, and measles will slowly spread from susceptible individual to susceptible individual. Dip below 75% immunity, and whooping cough will inexorably spread. Sure, the immune people are likely to be fine, but the people who need herd immunity because they can’t be immunized are at risk.

In other words, the unvaccinated child isn’t a threat to any specific individual child. My son probably won’t get chickenpox because your daughter never got vaccinated. But your hypothetical unvaccinated child is a potential threat to the entire community, taking the community one notch closer to falling below that critical immunity threshold that helps keep everyone safe.

Your hypothetical unvaccinated child is a chink in the armor of the community. And disease organisms are evolved to be really, really good at taking advantage of those weaknesses.


Yeah, wow.

Now look, I clearly got hot under the collar in my last article. I don’t regret that. Eradicating disease, and the suffering and death it causes, is worth a little passion. Because vaccines are demonstrably the single greatest medical discovery in the history of man, and they continue to work and they continue to benefit us despite a long history of people opposing them, often for no good reason at all. Fear. Ignorance. Rumor-mongering. Hucksters selling snake oil to profit off misery. And despite that, we’ve brought these disease to their knees, only to see them resurge as anti-intellectual frauds gain more and more publicity and find greater and greater outlets for their lies.

So, yeah. I get worked up. Because this is important. Sit down and talk to someone who lived through the polio epidemics. Talk to someone who’s nursed a child through whooping cough. Understand why this is important. And then do the right thing.

For everyone.

About Richard Gant

Richard Gant is a husband, a father, and a huge nerd with a deep love of science, science fiction, and fantasy. He works for a brokerage firm he won't name here in order to keep his Compliance department happy, and frequently talks to inanimate objects as if they can understand him. He also has a difficult time writing seriously about himself in the third person.
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15 Responses to …Then How Are Unvaccinated Children a Danger?

  1. Well said and said in a good and righteous cause.

    If only we could vaccinate against stupidity…

    But the herd-immunity factor is so weak for stupidity.

    Maybe the evolution juju doesn’t WANT us to survive; maybe we are a dispensible transitional stage…

    • WorkingInACopShop says:

      Well, the principles of evolution add up to: Whoever has the most grandchildren wins.

      I believe even now if you go to the trouble to look up the data from the last 200 years the Vaxers grandchildren outnumber the Anti-Vaxers. I expect they are in a higher tax bracket also.

      Don’t yell at me, just go look it up.

  2. Macky says:

    The herd-mindset might also be another point of discussion i.e. the authenticity of science and statistics (both questionable) as reasons/evidence why we should ALL get jabbed directly into the bloodstream with substances which are difficult to find out about.

    And even then, are pharma companies telling the truth ? They have a poor record so far.

    Another point to consider is where the stuff is made. Much meds are manufactured in India, with a doubtful record of clean practices.

    I’m thankful for the polio and tetanus vacs I was treated with in the 50’s.

    I would be skeptical of the same standards of manufacture/practice in today’s world.

    • Steven Gelfond says:

      Ah, a conspiracy theorist comes in as troll #1.

      • Macky says:

        “Steven Gelfond says:
        Ah, a conspiracy theorist comes in as troll #1.”

        If you’re referring to me, I am not a troll, and certainly not a conspiracy theorist.

        Every time a pharma company behaves in a criminal manner, science itself takes a knock, because at that point there is no guarantee that solid science has been maintained in the research and manufacture/distribution of drugs/vaccines.

        There is also the blatant conflict of interest re companies doing the tests on their own drugs/vaccines, and the promotion of said meds for maladies for which they have not been approved, dirty drugs from India etc.

        It’s a huge leap of faith when one is prepared to have stuff injected directly into one’s bloodstream, given the above.

        Not to mention the sordid record of unethical experiments on thousands of US citizens over the decades.

        Is it any wonder many are suspicious (WITHOUT any conspiracy theories) of the “latest wonder-drug/vaccine etc).

        • Doctor Futurity says:

          You are engaging in conspiracy-think, though. You can actually find out details on what a given vaccination contains, where it is made, and who made it. These are not incredibly difficult questions to answer, if you are concerned about them.

          Maybe you’re not a conspiracy theorist, but you might have some issues with understanding math/statistics. Example: you mention “thousands of US citizens affected by unethical experiments” over the decades. There’s nothing conspiratorial about that….we know of some well-documented cases. But to conclude that this means that one must be suspicious of all medical procedures going forward is to suggest that you also give no weight to the many hundreds millions of US citizens benefited by completely legitimate, ethical procedures over those same decades. One of these does not weigh like the other….

          • Noah Dillon says:

            Macky loves to claim that he’s not a conspiracy peddler before, during, and after he’s tried to pass off a lot of nonsense.

          • Macky says:

            What is conspiracy-think when I have never promoted or entertained ANY conspiracy either on the old Skeptoid or on here ?

            I agree with vaccines to improve immunity and health in the wider community, but it is not only unethical experiments in the US that show an appalling record of medical predation on citizens, but criminal off-label promotion of medicines for which they have not been approved.
            Here’s a piece of evidence for that https://en.wikipedia.org/wiki/List_of_largest_pharmaceutical_settlements
            It will forever remain unknown how many people were adversely affected by the above, and other similar criminal applications of medicines.

            As I said, given the above, one has every right to be suspicious of any new medicine/vaccine.
            The reputation of the very best research and manufacture of medicines takes a knock every time a pharma company is convicted of criminal activity.

            Why shouldn’t hundreds of millions of citizens continue to benefit from vaccines without the suspicion that what is being injected into their blood stream may be inappropriate for the stated purpose ?

    • mudguts says:

      Macky??? have you come off the drugs?? Your post is questionable as usual..

  3. Gary Dunning says:

    It’s regrettable that the scientific detail lacks the cachet of know nothing talk show celebrities demonizing vaccines on daytime TV, never mind rampant ‘Chicken Little’ vaccine conspiracy advocates in the general public. You need a bigger ‘Science Guy’ presence.

  4. Wm J Granger says:

    Richard, I think this is one of the clearest and most concise explanations of herd immunity and as a corollary, why vaccination is so important. I think this should be published in every local newspaper.

  5. Macky says:

    Vaccines are good. They provide the herd with a degree of immunity against serious diseases.

    The day Big Business cleans up it act re vaccines/meds and is demonstrably so, will be the day the bulk of the public (i.e. those that are sober skeptics not conspiracy theory Moon-gazers) may regain some confidence that the latest vaccine etc that is being notified for general use is not dirty, or unscientically promoted.


    Given the small link sample above, why shouldn’t the public have the right to be suspicious ?

    The assurance that the latest medicine has been scientifically formulated doesn’t mean a thing when it is not correctly and ethically employed.

  6. Macky says:

    “Noah Dillon says:
    April 7, 2017 at 11:17 pm
    Macky loves to claim that he’s not a conspiracy peddler before, during, and after he’s tried to pass off a lot of nonsense.”

    Quote some of the alleged nonsense you’re talking about Noah. I’ve always promised I would change my views and publicly say so in the light of better evidence than mine re my criticisms of the Official Story, but so far you’ve never had any answers to solid evidence and plain logic that I’ve posted on several issues.

    • Noah Dillon says:

      I’m not getting into this with you again. It’s a load of malarky. And in any case, the record is pretty well established for anyone who wants to look on the blog. It used to be on the episode pages, too, but those threads got closed after being swamped with hokum. Forget it. Arguing with stubborn people, even those who claim they’re not, who actively avoid or discount or ignore evidence contrary to their preferred beliefs, is, I’ve found, a waste of time.

      • Macky says:

        You never provided a shred of evidence contrary to my alleged “preferred beliefs”, which I’ve always said I would change if in fact you had, and it was better than mine.

        So what are you talking about ?

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