The U.S. officially eliminated measles nearly 20 years ago. Yet, this year, more than 1,100 cases have been reported, despite being preventable by vaccine. The CDC says the majority of cases are among those who were not vaccinated. This Forum looked at the drivers of the 2019 outbreaks and, more generally, the challenges of vaccine acceptance. Why do some parents delay or decline vaccinating their children? How might their concerns be addressed? What about exemptions? Why does the global picture matter? And what can be done once an outbreak begins? New polling data framed this discussion, providing a uniquely current picture of vaccine acceptance in the U.S. Part of The Dr. Lawrence H. and Roberta Cohn Forums, this event was presented jointly with PRI's The World & WGBH on September 12, 2019. Watch the entire series: https://theforum.sph.harvard.edu/