As of a few years ago at least, there was still Mercury in some children's vaccines. Our pediatrician had trouble finding a thimerosal-free source for a few of them. Thimerosal is still present in adult flu vaccines. Ask about it the next time you're offered a flu shot.
One of the vexing problems about this debate is that there's a well-established cumulative effect to Mercury exposure. But the company behind any one vaccine can say, with a mostly straight face, that carefully-controlled studies show that theirs doesn't cause problems. The operative phrase "by itself" is left unspoken. Unfortunately, the trend has been to to give kids more and more shots at an early age. There's also some evidence that the proteins responsible for scrubbing the body of heavy metals are missing in some people, leading to an uneven distribution of cases. A shot of bourbon by itself probably won't cause lasting problems, but a bunch of different whiskies all at once might, particularly if you lack the genes for metabolizing alchohol.