SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is a coronavirus that causes COVID-19, the respiratory illness responsible for the COVID-19 pandemic that began in late 2019. The virus previously had the provisional name 2019 novel coronavirus (2019-nCoV), and has also been called human coronavirus 2019 (HCoV-19 or hCoV-19). First identified in the city of Wuhan, Hubei, China, the World Health Organization designated the outbreak a public health emergency of international concern from January 30, 2020, to May 5, 2023. SARS‑CoV‑2 is a positive-sense single-stranded RNA virus that is contagious in humans.

SARS‑CoV‑2 is a virus of the species Betacoronavirus pandemicum (SARSr-CoV), as is SARS-CoV-1, the virus that caused the 2002–2004 SARS outbreak. Some animal-borne coronaviruses are more closely related to SARS-CoV-2 than SARS-CoV-1 is. The closest known relative is the BANAL-52 bat coronavirus. SARS-CoV-2 is of zoonotic origin; its close genetic similarity to bat coronaviruses suggests it emerged from such a bat-borne virus. Research is ongoing as to whether SARS‑CoV‑2 came directly from bats or indirectly through any intermediate hosts. The virus shows little genetic diversity, indicating that the spillover event introducing SARS‑CoV‑2 to humans is likely to have occurred in late 2019.