ased ▁by ▁over ▁ 9 9 % ▁in ▁the ▁US ▁since ▁the ▁introduction ▁of ▁a ▁v acc ine ▁in ▁ 1 9 8 8 . ▁It ▁is ▁estimated ▁that ▁full ▁v acc ination , ▁from ▁birth ▁to ▁ad oles c ence , ▁of ▁all ▁US ▁children ▁born ▁in ▁a ▁given ▁year ▁would ▁save ▁ 3 3 , 0 0 0 ▁lives ▁and ▁prevent ▁ 1 4 ▁million ▁in fe ctions . ▁ ▁Some ▁argue ▁that ▁these ▁redu ctions ▁in ▁inf ect ious ▁disease ▁are ▁a ▁result ▁of ▁improved ▁san itation ▁and ▁h yg iene ▁( r ather ▁than ▁v acc ination ), ▁or ▁that ▁these ▁dise ases ▁were ▁already ▁in ▁decl ine ▁before ▁the ▁introduction ▁of ▁specific ▁v acc ines . ▁These ▁claims ▁are ▁not ▁supported ▁by ▁scientific ▁data ; ▁the ▁inc idence ▁of ▁v acc ine - prevent able ▁dise ases ▁t ended ▁to ▁fl uct uate ▁over ▁time ▁until ▁the ▁introduction ▁of ▁specific ▁v acc ines , ▁at ▁which ▁point ▁the ▁inc idence ▁dropped ▁to ▁near ▁zero . ▁A ▁Cent ers ▁for ▁D ise ase ▁Control ▁and ▁Pre vention ▁website ▁aim ed ▁at ▁counter ing ▁common ▁mis con ception s ▁about ▁v acc ines ▁argued , ▁" Are ▁we ▁expected ▁to ▁believe ▁that ▁better ▁san itation ▁caused ▁inc idence ▁of ▁each ▁disease ▁to ▁drop , ▁just ▁at ▁the ▁time ▁a ▁v acc ine ▁for ▁that ▁disease ▁was ▁introduced ?" ▁ ▁Other ▁critics ▁argue ▁that ▁the ▁imm unity ▁granted ▁by ▁v acc ines ▁is ▁only ▁temporary ▁and ▁requires ▁boost ers , ▁whereas