A defined regimen of media changes are used to establish {HEAD ~ a quiescent and nonproductive state} following {TAIL ~ the withdrawal} of the antiviral treatment 
following
A defined regimen of media changes are used to establish { HEAD ~ a quiescent and nonproductive state } following { TAIL ~ the withdrawal } of the antiviral treatment
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH