In epidemiology, a pandemic is defined as "an epidemic occurring over a very wide area, crossing international boundaries, and usually affecting a large number of people". During the COVID-19 pandemic, as with oth… See more

SARS-CoV-2 is a virus closely related to bat coronaviruses, pangolin coronaviruses, and SARS-CoV. The first known outbreak (the 2019–2020 COVID-19 outbreak in mainland China) started in Wuhan, Hubei, China, in December … See more

Several variants have been named by WHO and labelled as a variant of concern (VoC) or a variant of interest (VoI). Many of these variants have shared the more infectious D614G. As of May 2023, the WHO had … See more

Many countries attempted to slow or stop the spread of COVID-19 by recommending, mandating or prohibiting behaviour changes, while others relied primarily on providing information. Measures ranged from public … See more

The outbreak was discovered in Wuhan in November 2019. It is possible that human-to-human transmission was happening before the discovery. Based on a retrospective analysis starting from December … See more