At least 179 American children died of flu last year, the highest since 2004, when doctors began reporting confirmed influenza cases to federal authorities. Despite that record number, about one-third of parents in a new poll by the University of Michigan’s C. S. Mott Children’s Hospital said they didn’t intend to vaccinate their children against the influenza virus this season. Parents underestimate the dangers, especially if their kids are in good health, but half of the kids who die of flu are otherwise healthy. That figure doesn’t surprise Sarah Clark, the poll’s co-director and an associate research scientist in the university hospital’s pediatrics department.