Coronaviruses are a large and diverse family of viruses that cause illnesses such as the common cold. Other recent diseases caused by coronaviruses include severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).

SARS-CoV-2 was first recognised in China and likely originated in animals. It is still unclear how the virus came to infect humans. The disease spread to other countries, with the World Health Organization (WHO) declaring a pandemic on 11 March 2020.

The virus has since undergone genetic mutations over time as it adapts to humans. Some of these mutations can spread more easily than the original virus.