The World Health Organization listed vaccine hesitancy -- when parents delay or withhold vaccines for their children -- as one of the Top 10 health risks for 2019. Now, with more than 700 confirmed cases of measles in 23 states, public health officials are scrambling to put a stop to it. Dr. Jon LaPook reports on health experts using science as an antidote to misinformation about vaccines. Air Date: May 12, 2019