Is it permissible to immunize or vaccinate babies even though many vaccines or immunizations contain pork and other haram ingredients?

Religious Authority: 
Faraz Fareed Rabbani
Fatwa Question or Essay Title: 
Is it permissible to immunize or vaccinate babies even though many vaccines or immunizations contain pork and other haram ingredients?
Websites and Institutions: 
Sunni Path, (New Brunswick, New Jersey, U.S.)

It is permitted to take immunizations and vaccines, and to assume that they are from pure ingredients. If it is specifically established otherwise, then one should consult with scholars about the specifics of the situation.