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What are coronaviruses?

Coronaviruses (CoV) are a large family of respiratory viruses that can cause mild to moderate illnesses, ranging from the common cold to respiratory syndromes such as MERS (Middle East Respiratory Syndrome) and SARS (Severe Acute Respiratory Syndrome). They are named for the crown-like spikes on their surface, “corona” being the Latin for “crown”.


Coronaviruses are common in several animal species (including camels and bats), but in rare cases can evolve to infect humans and then spread between people. A novel coronavirus is a new strain of coronavirus that has not been previously identified in humans.


To date, there are seven known types of human coronaviruses that are common throughout the world. The first ones were identified in the mid-1960s, while others were only detected in the new millennium.


Common human coronaviruses

1 - 229E (alpha coronavirus)

2 - NL63 (alpha coronavirus)

3 - OC43 (beta coronavirus)

4 - HKU1 (beta coronavirus)


Other human coronaviruses

5 - MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome)

6 - SARS-CoV (the beta coronavirus that causes Severe Acute Respiratory Syndrome)

7 - SARS-CoV-2 (the coronavirus that causes COVID-19)



On 9 January 2020, the WHO declared that Chinese health authorities had detected a new strain of coronavirus that had not been previously identified in humans. Provisionally named 2019-nCoV, and later officially classified and designated as SARS-CoV-2, the virus was associated to a cluster of pneumonia cases first reported on 31 December 2019 in the city of Wuhan, in central China. On 11 February, the WHO announced that the respiratory disease caused by the novel coronavirus had been named COVID-19 (Corona Virus Disease 2019).
Please note: this is a rapidly-evolving situation, so the information provided in these pages may not always reflect the latest available data and information.

Publication date: January 23, 2020

Authors: Giovanni Rezza, Antonino Bella, Flavia Riccardo, Patrizio Pezzotti - Dipartimento Malattie infettive, ISS