A bit of context. Mr Mihalovic is not a doctor, but an anti-vaccine advocate and a "naturopath" -- in other words:
David Mihalovic is an ND, which stands for “naturopathic doctor” or, more appropriately, “not a doctor”. According to himself he “specializes in vaccine research.” It is, however, unclear where that research is published – there are no hits on Pubmed, for instance – though he does write propaganda for the anti-vaccine website Medical Voices Vaccine Information Center.
I don't know if this quote is made up or not, but the most similar thing I could find is this image which is about "synergistic" toxicity.
He referst to this article which was written by authors in an undisclosed conflict of interest, they are funded by anti-vaccination propaganda groups. In any case, the article has been thoroughly debunked, and, if you think of it, it also contradicts the claim of Mihailovic.
Mihalovic claims that some vaccines, when used together, are toxic/deadly: a bit like two-part glue, if you like. The authors of the debunked article claim that the number of shots is relevant -- which is ludicrous, of course -- and that they found a linear relationship between the number of shots taken (they call them "vaccines", but it's not what they are) and infant mortality.
There's also another link that claims that vaccines cause type I diabetes, but that seems off-topic with respect to the original claim. Unsurprisingly, it's also written by a person which holds patents on "methods of testing vaccines for their ability to cause diabetes and methods of preventing diabetes", in other words, who has an open interest in making such claims.
TL:DR; Vaccines are safe. Lack of vaccination is irresponsible and causes harm to children and immunocompromised groups.