The "vaccines cause autism" thing never made much sense, and all the evidence is against it - but some people think autism is the worst possible thing that can "happen" to someone like it's some kind of disease, and it most certainly is not.

I'm aware of the antivaxxers pushing their stuff with animals too - homeopaths do this as well, and homeopathy might be a good subject for my next post considering how popular it seems to be despite being literally just water.