The Trump-appointed head of the federal panel that recommends vaccines is saying that polio and measles vaccines—and perhaps every vaccine—should be optional. Dr. Kirk Milhoan, who heads the Advisory Committee on Immunization Practices at the Centers for Disease Control and Prevention, said on a podcast Thursday that possibly every shot should be optional , saying that while he had “concerns” that some children might die of measles or become paralyzed from polio, a person’s right to refuse a