These vaccines are useful for {HEAD ~ administration} to {TAIL ~ humans} and other animals at risk of exposure to C. difficile toxins 
to
These vaccines are useful for { HEAD ~ administration } to { TAIL ~ humans } and other animals at risk of exposure to C. difficile toxins
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH