COVID-19, which stands for coronavirus disease 2019, is caused by a virus named SARS-CoV-2, a type of coronavirus. Coronaviruses can cause the common cold or more severe diseases such as SARS, MERS and COVID-19, the latter of which first appeared in late 2019 in Wuhan, China. The World Health Organization has declared the COVID-19 outbreak a global pandemic, the first caused by a coronavirus.