May 25 JDN 2460821

Vaccines are one of the greatest accomplishments in human history. They have saved hundreds of millions of lives with minimal cost and almost no downside at all. (For everyone who suffers a side effect from a vaccine, I guarantee you: Someone else would have had it much worse from the disease if they hadn’t been vaccinated.)

It’s honestly really astonishing just how much good vaccines have done for humanity.

Thus, it’s a bit of a mystery how there are so many people who oppose vaccines.

But this mystery becomes a little less baffling in light of behavioral economics. People assess the probability of an event mainly based on the availability heuristic: How many examples can they think of when it happened?

Precisely because vaccines have been so effective at preventing disease, we have now reached a point where diseases that were once commonplace are now virtually eradicated. Thus, parents considering whether to vaccinate their children think about whether they know anyone who has gotten sick from that disease, and they can’t think of anyone, so they assume that it’s not a real danger. Then, someone comes along and convinces them (based on utter lies that have been thoroughly debunked) that vaccines cause autism, and they get scared about autism, because they can think of someone they know who has autism.

But of course, the reason that they can’t think of anyone who died from measles or pertussis is because of the vaccines. So I think we need an educational campaign that makes these rates more vivid for people, which plays into the availability heuristic instead of against it.

Here’s my proposal for a little educational game that might help:

It functions quite similarly to a classic tabletop RPG like Dungeons & Dragons, only here the target numbers are based on real figures.

Gather a group of at least 100 people. (Too few, and the odds become small enough that you may get no examples of some diseases.)

Each person needs 3 10-sided dice. Preferably they would be different colors or somehow labeled, because we want one to represent the 100s digit, one the 10s digit, and one the 1s digit. (The numbers you can roll thus range uniformly from 0 to 999.) In TTRPG parlance, this is called a d1000.

Give each person a worksheet that looks like this:

Disease	Before vaccine: Caught?	Before vaccine: Died?	After vaccine: Caught?	After vaccine: Died?
Diptheria
Measles
Mumps
Pertussis
Polio
Rubella
Smallpox
Tetanus
Hep A
Hep B
Pneumococca
Varicella

In the first round, use the figures for before the vaccine. In the second round, use the figures for after the vaccine.

For each disease in each round, there will be a certain roll that people need to get in order to either not contract the disease: Roll that number or higher, and you are okay; roll below it, and you catch the disease.

Likewise, there will be a certain roll they need to get to survive if they contract it: Roll that number or higher, and you get sick but survive; roll below it, and you die.

Each time, name a disease, and then tell people what they need to roll to not catch it.

Have them all roll, and if they catch it, check off that box.

Then, for everyone who catches it, have them roll again to see if they survive it. If they die, check that box.

Based on the historical incidences which I have converted into lifetime prevalences, the target numbers are as follows:

Disease	Before vaccine: Roll to not catch	Before vaccine: Roll to survive	After vaccine: Roll to not catch	After vaccine: Roll to survive
Diptheria	13	87	0	0
Measles	244	1	0	0
Mumps	66	0	2	0
Pertussis	123	20	4	2
Polio	20	89	0	0
Rubella	19	1	19	0
Smallpox	20	12	0	0
Tetanus	1	800	1	71
Hep A	37	1	4	1
Hep B	22	4	4	4
Pneumococca	19	103	11	119
Varicella	950	1	164	0

What you should expect to see for a group of 100 is something like this (of course the results are random, so it won’t be this exactly):

Disease	Before vaccine: Number caught	Before vaccine: Number died	After vaccine: Number caught	After vaccine: Number died
Diptheria	1	0	0	0
Measles	24	0	0	0
Mumps	7	0	0	0
Pertussis	12	1	0	0
Polio	2	0	0	0
Rubella	2	0	0	0
Smallpox	2	0	0	0
Tetanus	0	0	0	0
Hep A	4	0	0	0
Hep B	2	0	0	0
Pneumococca	2	1	1	1
Varicella	95	0	16	0

You’ll find that not a lot of people have checked those “dead” boxes either before or after the vaccine. So if you just look at death rates, the difference may not seem that stark.

(Of course, over a world as big as ours, it adds up: The difference between the 0.25% death rate of pertussis before the vaccine and 0% today is 20 million people—roughly the number of people who live in the New York City metro area.)

But I think people will notice that a lot more people got sick in the “before-vaccine” world than the “after-vaccine” world. Moreover, those that did get sick will find themselves rolling the dice on dying; they’ll probably be fine, but you never know for sure.

Make sure people also notice that (except for pneumococca), if you do get sick, the roll you need to survive is a lot higher without the vaccine. (If anyone does get unlucky enough to get tetanus in the first round, they’re probably gonna die!)

If anyone brings up autism, you can add an extra round where you roll for that too.

The supposedly “epidemic” prevalence of autism today is… 3.2%.

(Honestly I expected higher than that, but then, I hang around with a lot of queer and neurodivergent people. (So the availability heuristic got me too!))

Thus, what’s the roll to not get autism? 32.

Even with the expansive diagnostic criteria that include a lot of borderline cases like yours truly, you still only need to roll 32 on this d1000 to not get autism.

This means that only about 3 people in your group of 100 should end up getting autism, most likely fewer than the number who were saved from getting measles, mumps, and rubella by the vaccine, comparable to the number saved from getting most of the other diseases—and almost certainly fewer than the number saved from getting varicella.

So even if someone remains absolutely convinced that vaccines cause autism, you can now point out that vaccines also clearly save billions of people from getting sick and millions from dying.

Also, there are different kinds of autism. Some forms might not even be considered a disability if society were more accommodating; others are severely debilitating.

Recently clinicians have started to categorize “profound autism”, the kind that is severely debilitating. This constitutes about 25% of children with autism—but it’s a falling percentage over time, because broader diagnostic criteria are including more people as autistic, but not changing the number who are severely debilitated. (It is controversial exactly what should constitute “profound autism”, but I do think the construct is useful; there’s a big difference between someone like me who can basically function normally with some simple accommodations, and someone who never even learns to talk.)

So you can have the group do another roll, specifically for profound autism; that target number is now only 8.

There’s also one more demonstration you can do.

Aggregating over all these diseases, we can find the overall chance of dying from any of these diseases before and after the vaccine.

Have everyone roll for that, too:

Before the vaccines, the target number is 8. Afterward, it is 1.

If autism was brought up, make that comparison explicit.

Even if 100% of autism cases were caused by vaccines (which, I really must say, is ridiculous, as there’s no credible evidence that vaccines cause autism at all) that would still mean the following:

You are trading off a 32 in 1000 chance of your child being autistic and an 8 in 1000 chance of your child being profoundly autistic, against a 7 in 1000 chance of your child dying.

If someone is still skeptical of vaccines at this point, you should ask them point-blank:

Do you really think that being autistic is one-fifth as bad as dying?

Do you really think that being profoundly autistic is as bad as dying?