If you're not one of them, then you already know that anti-vaxxers are today's village idiots. There's enough literature out there that proves vaccines' efficacy and deflates anti-vax bullshit, I'm not here to make that case. But I do want to mention a little something for the already-vaccinated adults with already-vaccinated children out there.
When I wanted to take a class at my University, I had to prove that I had up-to-date vaccines (funny, I never had to prove that to stand in front of college students, only to sit next to them). The only evidence I had of any immunities was a little red card folded in half, and on it was my mother's handwriting noting dates in the 1970's and 80's when I had various boosters.
Obviously, this wasn't good enough. I needed to go to a local hospital and have an inexpensive blood titer performed to produce the evidence I needed that I was in fact immunized as a child, and I was pleased to have definitive proof on record.
Then I got a call to tell me that the test was negative.
"What, like negative like I don't have any diseases?" I asked.
"No," the physician's assistant said, "negative like you're not immunized."
"Not against anything?"
"Just measles. You're immune to everything but measles."
As you may remember, the MMR vaccine stands for Measles, Mumps, and Rubella, wrapping immunity for three nasty diseases into one shot. So if I did get the shots, how come I was only vulnerable to one of them? That's when she hit me with it: I had the shots, it's just that the measles part didn't stick.
Think for a moment. I had all my shots as a baby, and boosters later on. But the immunity to measles did not stick, which is something that happens sometimes. The only reason I was never infected by the super-contagious rubeola virus is because everybody else was immune.
Now, measles sucks and is not something you want to get as an adult, but it's not like I'd die or be permanently debilitated if I'd caught it. But it makes it easy to really grasp the concept of herd immunity. If that had been something like polio, it's chilling, and made viscerally clear to me how dangerous anti-vaxxers actually are.
They are clearly not the critical thinkers they illustrate themselves to be, but they are not merely a fringe group of harmless morons not hurting anyone but themselves. Statistically, yes, they're harming their own children more than everyone else, which might not be so bad if you take the crass attitude that "well, they're just weeding out their own gene pool." But even that isn't true, any one of us or our children might have a hole in our defenses, but the reason it works as well as it does is because on the whole everybody is protected. That system must not fall apart.