Most people's understanding of vaccines, vaccination and the diseases they prevent is gleaned from the printed media, but published anti-vaccination arguments may unduly influence them.
(they; prevent; ) (Most people's understanding of vaccines, vaccination and the diseases; is gleaned; from the printed media) (published anti-vaccination arguments; may unduly influence; them)
they Most people's understanding of vaccines, vaccination and the diseases published anti-vaccination arguments
prevent is gleaned may unduly influence
from the printed media
them