(Update: links fixed)
It is not uncommon in this life for people with no basic knowledge of science/medicine/biology/you name it to grab hold of an idea with all the fixity of a tumour-free Tasmanian Devil grabbing hold of a large steak and, refusing to let go, get lifted off the ground by the Park Ranger of actual fact and be left without a leg to stand on.
There are creationists who can't seem to grab the simplest principles of evolution. Flat-earthers who can't grab the simplest principles of gravity. Moon-landing denialists who refuse to listen when people patiently explain away all the things that their earth-bound experience has trouble with.
But although these things may reduce the average level of knowledge or even intelligence of the general population, and may even faintly reduce the pace of progress or even stall it altogether through limiting community or political (and therefore financial) support, few wacko, woo-woo, denialist beliefs are quite so dangerous as the "Vaccines cause autism" crowd, who are slowly dragging us back from the brink of all-but-eradicating measles, whooping couch and others to the point where, once again, hospital beds and graves are being filled by preventable diseases and complications such as encephalitis or meningitis are causing very real long-term disabilities and, just for added irony value, potentially causing autism through pregnant mothers catching rubella.
I was looking, a while back, for a good website which collected their scatter-brained arguments and summarised the (really quite simple to understand, for the most part) rebuttals from actual science. There wasn't one, so I started compiling my own list of web resources here.
Well, now there is a website I can reference.
First, a bit of background: The whole stupid scare really got off the ground in the UK with a "professional witness" for vaccination injury lawyers called Andrew Wakefield. But the face of vaccination denialism in the USA, where most of the debate is happening, is a former Playboy Playmate and current actress called Jenny McCarthy. To add some proper celebrity endorsement to the united ineptitude of her cause, she's boffing Jim Carey and now he's putting his foot in his mouth on a regular basis to back her up.
And so the website to go to for a nice concise overview of the vaccination denialism nonsense is called, unfortunately for its international relevance, Stop Jenny McCarthy.
Go there. Read it. And stop trying to abuse the concept of intelligence by saying things like "But vaccines have formaldehyde in them!" or "I hear what you're saying, but I just wonder why there are so many children being diagnosed with autism". Stop fucking wondering, and start listening to the answers.