The measles outbreak in the United States is an aberration. Since 2000, measles cases have declined substantially around the world thanks to a worldwide effort known as the Measles and Rubella Initiative. Its goal is to eliminate measles all together by 2020. But is that realistic? And what would elimination entail? Mark speaks with epidemiologist Dr. Rebecca Martin of the U.S. Centers for Disease Control and Prevention who puts the US outbreak in a global context. She discusses why epidemiologists are so concerned about the American outbreak; what accounts for the overall decline globally; and what needs to be done to reach that 2020 target.