When any author uses hyperbolic statement like this you know he is full of sh!t.
Mercury is toxic but it hardly can be termed one of the most toxic substances known to mankind.
Also go to this Thirmerasol Table and you can see that thirmerasol is used in very few vaccines and in those that do use it there is very little of it.
Also Mercury is bad, but in the amounts in vaccines is quite low.
You would get more eating tuna.
I think accelerants in vaccines are to blame.