ens ▁that ▁have ▁been ▁grown ▁in ▁culture ▁and ▁then ▁lose ▁disease ▁producing ▁capacity . ▁In ▁contrast , ▁live ▁v acc ines ▁use ▁path og ens ▁that ▁are ▁still ▁alive ▁( but ▁are ▁almost ▁always ▁at ten u ated , ▁that ▁is , ▁weak ened ). ▁Path og ens ▁for ▁in activ ated ▁v acc ines ▁are ▁grown ▁under ▁controlled ▁conditions ▁and ▁are ▁killed ▁as ▁a ▁means ▁to ▁reduce ▁inf ect ivity ▁( vir ul ence ) ▁and ▁thus ▁prevent ▁in fection ▁from ▁the ▁v acc ine . ▁The ▁virus ▁is ▁killed ▁using ▁a ▁method ▁such ▁as ▁heat ▁or ▁formal de hy de . ▁▁ ▁In activ ated ▁v acc ines ▁are ▁further ▁class ified ▁depending ▁on ▁the ▁method ▁used ▁to ▁in activ ate ▁the ▁virus . ▁Wh ole ▁virus ▁v acc ines ▁use ▁the ▁entire ▁virus ▁particle , ▁fully ▁destroyed ▁using ▁heat , ▁chemical s , ▁or ▁radiation . ▁Split ▁virus ▁v acc ines ▁are ▁produced ▁by ▁using ▁a ▁d eter gent ▁to ▁dis rupt ▁the ▁virus . ▁Sub unit ▁v acc ines ▁are ▁produced ▁by ▁pur ifying ▁out ▁the ▁ant ig ens ▁that ▁best ▁stim ulate ▁the ▁imm une ▁system ▁to ▁mount ▁a ▁response ▁to ▁the ▁virus , ▁while ▁removing ▁other ▁components ▁necessary ▁for ▁the ▁virus ▁to ▁rep licate ▁or ▁surv ive ▁or ▁that ▁can ▁cause ▁ad verse ▁re actions . ▁ ▁Because ▁in activ ated ▁vir uses ▁tend ▁to ▁produce ▁a ▁we aker ▁response ▁by ▁the ▁imm une ▁system ▁than ▁live ▁vir uses , ▁imm un olog ic ▁adj uv ants