In December 2019, in Wuhan, China, a cluster of patients were admitted to the hospital with a diagnosis of "pneumonia of uncertain etiology." The first case was reported to the WHO country office in China on December 31, 2019.

By January 2, 2020, 41 patients were identified as having the novel infection, later identified and named COVID-19, an acronym for coronavirus disease 2019. The causative agent was identified as SARS-CoV-2.

The 425 patients reported with Novel Coronavirus-Infected Pneumonia in Wuhan were linked to the Huanan wholesale seafood market. When writing this course on the 28/11/2021, COVID-19 has globally affected 262,000,000 people worldwide, including 5,200,000deaths.