A pandemic is a global outbreak of disease that happens when a new virus emerges to infect people. It spreads worldwide because there is little to no pre-existing immunity against the new virus. The virus that caused COVID-19 is spreading easily from person-to-person. Cases have been detected worldwide and community spread has been detected in a growing number of countries. On March 11, 2020 the COVID-19 outbreak was characterized as a pandemic by the WHO.