A AP ) ▁asked ▁v acc ine ▁mak ers ▁to ▁remove ▁th iom ers al ▁from ▁v acc ines ▁as ▁quickly ▁as ▁possible ▁on ▁the ▁pre ca ution ary ▁principle . ▁Th iom ers al ▁is ▁now ▁absent ▁from ▁all ▁common ▁US ▁and ▁European ▁v acc ines , ▁except ▁for ▁some ▁prepar ations ▁of ▁influen za ▁v acc ine . ▁Trace ▁amounts ▁remain ▁in ▁some ▁v acc ines ▁due ▁to ▁production ▁processes , ▁at ▁an ▁approximate ▁maximum ▁of ▁ 1 ▁micro gram me , ▁around ▁ 1 5 % ▁of ▁the ▁average ▁daily ▁mer cur y ▁int ake ▁in ▁the ▁US ▁for ▁adult s ▁and ▁ 2 . 5 % ▁of ▁the ▁daily ▁level ▁considered ▁toler able ▁by ▁the ▁W HO . ▁The ▁action ▁spark ed ▁concern ▁that ▁th iom ers al ▁could ▁have ▁been ▁responsible ▁for ▁aut ism . ▁The ▁idea ▁is ▁now ▁considered ▁dis pro ven , ▁as ▁inc idence ▁rates ▁for ▁aut ism ▁increased ▁stead ily ▁even ▁after ▁th iom ers al ▁was ▁removed ▁from ▁child hood ▁v acc ines . ▁Currently ▁there ▁is ▁no ▁accepted ▁scientific ▁evidence ▁that ▁expos ure ▁to ▁th iom ers al ▁is ▁a ▁factor ▁in ▁causing ▁aut ism . ▁Since ▁ 2 0 0 0 , ▁parents ▁in ▁the ▁United ▁States ▁have ▁purs ued ▁legal ▁compens ation ▁from ▁a ▁federal ▁fund ▁arg uing ▁that ▁th iom ers al ▁caused ▁aut ism ▁in ▁their ▁children . ▁A ▁ 2 0 0 4 ▁Institute ▁of ▁Medicine ▁( IO M ) ▁committee ▁fav ored ▁reject ing ▁any ▁caus