Applied probabilities

Code 2 for unknown injury.

A toddler has a gaping laceration, likely caused by the a rusty, aged, outdoor chain-link fence around his residence.

“Has he had a Tetanus shot?”

“We don’t believe in vaccines.”

“Umm… Okaaaaaay…”

“We have our reasons.”

“Really… you know what Tetanus is? Or maybe you’ve never heard of polio?”

The mother then has the same exact conversation with the ED attending.

I’m certainly not an expert in infectious diseases and vaccines, but I do know a thing or two about statistics and probabilities.

Over the years some very smart people figured out that there are some very dangerous and sometimes incurable scary diseases that you don’t want to catch. And then they figured out how to inoculate you so you don’t even contract these diseases. Some of these diseases were even declared eradicated a long time ago.

If you believe vaccines are a bigger threat to you and your children than the diseases they aim to prevent, then clearly you either have a fuzzy grasp of probabilities or are immune to facts. Which is a little ironic that you’re turning down the acquired immunity.

Believe what you want, but to me it’s quite simple.

Let v be the chance of a certain vaccine causing harm (such as MMR causing autism), and d be the chance of contracting the horrible disease(s) the vaccine is supposed to prevent (such as MMR).

If v > d, then don’t get the vaccine.

If v < d, then get the vaccine.

Let’s say that v = 0, because that’s the scientific consensus, multiple studies have failed to establish any connection, and Andrew Wakefield’s high-profile study claiming a link between autism and vaccines has been thoroughly discredited as flat-out fraudulent, not to mention it was based on “anecdotal evidence” on 12 kids, a statistically minuscule sample size, which, if you know anything about statistics, means absolutely nothing.

As for d, we know that it is a positive number not zero. In fact, d increases in value with the increase in the number of unvaccinated people.

Therefore, v < d.

It’s pretty simple.

Get vaccinated.

It’s a huge public health issue.

Then again, I suppose if human beings understand anything about risk, they would wear their seat belts and never start smoking. But they don’t.

*So I originally had a whole bunch of links prepared for this post when I started writing this nearly a year ago, but thanks to the Disney outbreak, the (near-)universal condemnation of anti-vaxxers has made the links unnecessary. But I will include a timeline from The Onion. You’re welcome.

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