The Trump administration’s head of vaccines will leave the U.S. Food and Drug Administration next month following a tenure marked by several high-profile controversies. Dr. Vinay Prasad, who leads the FDA’s Center for Biologics Evaluation and Research, will depart at the end of April, the Wall Street Journal first reported Friday. Prasad, who joined the agency in May, oversaw several vaccine-related decisions that drew scrutiny, including his refusal last month to review a new influenza vaccine...