Vaccines
can
____________________
some
infectious
diseases
.
They
contain
weakened
or
dead
____________________
.
When
vaccines
are
administered
,
our
body
creates
____________________
to
fight
the
____________________
agents
.
Then
,
if
our
body
is
____________________
by
the
same
type
of
pathogen
,
it
is
ready
to
defend
itself
.
