RFK Jr. has hired at least four people with a history of criticizing vaccines, including the former president of his anti-vaccine groupRobert F. Kennedy Jr. spent much of his confirmation process before becoming the nation’s health secretary reassuring lawmakers that he would not undermine public confidence in vaccines and seeking to distance himself from the anti-vaccine group he founded, Children’s Health Defense. As health secretary, he has installed former prominent members of that group and other vaccine skeptics in positions at the department he runs or agencies it oversees. The appointment of officials from CHD, including a former president of...