"Vaccines are potentially lethal because they contain mercury, aluminum, monosodium glutamate, formaldehyde, and so on."

mercury: In vaccines there is ethylmercury which actually gets broken down by the body kinda quick. And the doses are really low. The more dangerous methylmercury is f.e. found in fish like tuna. So if you care about mercury - stop eating fish, don't stop vaccines ;)

aluminium: You care about makrophagic myofascilitis here right? Studies done 2008 showed that there was no correlation ;)

monosodium glutamate: This is used as spice for better taste - won't say more ;)

formaldehyde: Yes this is cancerogen - but in much larger doses. In one vaccine shot there is about 0,2 to 0,3mg of it. With food your DAILY input of it is about 1-15g. Do you really think the vaccine will matter here?

Yes, when not caring about the doses these ingredients sound dangerous. If you dig deeper you will see that you get more of them elseware all the time ;)
And vaccines also don't give the stuff directly in your blood stream. It gets injected into fat/muscle!

I hope that I could put some light into the dark! greets