Visualizing herd immunity

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I get why you’d say this, but really I don’t think they are doing anything of the sort. If you look at a Machiavellian game-theory approach to vaccines you might conclude that the safest thing to do for your own kid is avoid vaccination as long as you are the only one who does it. A sort of million-player prisoner’s dilemma.

But to come to that conclusion (which would be on shaky ground for all the normal prisoner’s dilemma related reasons) you’d need to have accurate information about the risks and benefits of the vaccine and the ability to do at least high school math. I doubt a single person has ever sat down with a pencil and a calculator to work it out and then based their decisions to vaccinate their children on the outcome.

I like these visualizations. But if they do change any minds it’s more likely because someone feels bad for the poor little dots than because it helps them understand math.


basically betting that either vaccines don’t work and/or vaccines aren’t safe and/or the diseases just aren’t that big a deal

Drop the “either” and change the "and/or"s to "or"s, and you’ll have a sentence – in fact, one that says what you intended.


Watching the highly infectious disease burn through the various populations is horrifying.

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<video ends with “Join The Herd”>

I get the impression that this slogan might be counterproductive on the kind of personalities who doubt vaccines…


I’ve done nearly the same presentation. The exact density where this happens depends on interconnectedness, but there tends to be a rather sharp phase transition (hence the physicist) where we go from diseases infecting few to infecting almost everyone. The graph below comes from running the “Forest Fire” variant of the model. (Exactly the same model except that trees don’t recover.)


We humans are more connected than static points on the plane, so the critical threshold is lower than the 40% density you see here. The point is, anyway, that things can look fine until they — all of a sudden — get a heck of a lot worse.


Pedantic epidemiologist quibble: in the close they said “immunity rate” needs to be higher to provide immunity for more infectious diseases. This should be “prevalence of immunity” not “immunity rate.”

Otherwise: kudos!

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So very true for many things. Structure fires come immediately to mind.


Also democratic and legal systems.

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