Pandemic smallpox was responsible for 300–500 million deaths. As recently as the early 1950s, an estimated 50 million cases of smallpox occurred in the world each year. After successful vaccination campaigns throughout the 19th and 20th centuries, the WHO certified the eradication of smallpox in December 1979. To this day, smallpox is the only human infectious disease to have been completely eradicated, and one of two infectious viruses ever to be eradicated. Historically, measles was prevalent throughout the world, as it is highly contagious. According to the U.S. National Immunization Program, 90% of people were infected with measles by age 15.
Who I Was Born to Be to Be" was composed by Johan Fransson, Tim Larsson, and Tobias Lundgren. Among her most notable performances of "Who I Was Born to Be", Boyle's first live performance of this song was on 7 December 2009 in London before an audience for the taping of her television special "". "Who I Was Born to Be" was used as the theme song for the anime "Welcome to the Space Show" which was released in 2010. Boyle performed the song on The Oprah Winfrey Show in Chicago on 19 January 2010. On 10 July 2011 she performed it in front of a