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