One evening last fall, Rachel McKibbens got a text from her younger brother, Peter. It read: “I’ve been too distraught to tell you, but Dad passed away today at 2:42 p.m.” She had no idea her father had even been sick, and no idea that her brother was also dying. They were unvaccinated, but the story of what happened started long before that. (44 minutes)

By Nancy Updike; Produced by Jenelle Pifer