(Found, almost certainly) Sci fi book from 70's?

[Lynntred]

Cant remember the name of book, i think i read it in the late 70's or early 80's. Science fiction...plot is- an evil doctor or scientist uses a radio transmitter or something of the sort to disrupt peoples immune systems and people start dying from whatever they dont have immunity to, ex..some die from the common cold, another from the chicken pox,,

 

[CassFrank]

This is The Deadly Messiah by David and Albert Hill (1977)

 

[Pyan]

As the OP hasn't been seen for over five years, I'll mark this a 'almost certainly', and change it if necessary. Can't really see any doubt, though.