A mercury-containing preservative that is used in some vaccines has not been used in childhood vaccines since 2001, according to the Despite his concerns about childhood vaccines, Hill would not support new restrictions on them while more research is conducted. "If there are people that want it, I think it should be available to them," said Hill, a supervisor at a nuclear power plant. "While you're studying, let be available." Hill is one of 20 Americans who voted for President Donald Still, each of thes ...