Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Coronaviruses are a large family of viruses, some of which infect only animals, and others that can infect humans. Seven strains of coronavirus are now known to cause illness in humans, three of which cause severe disease in humans: SARS-CoV-1, Middle East respiratory syndrome (MERS CoV) and SARS-CoV-2. SARS-CoV-2 and its disease COVID-19 were first identified in December 2019 in Wuhan, the capital of China’s Hubei province. The disease has since spread globally, resulting in the ongoing 2019–20 coronavirus pandemic.

COVID-19 signs and symptoms vary: from no symptoms (asymptomatic), to cold/flu-like symptoms, to neurological symptoms. The time from exposure to onset of symptoms is typically around five days but may range from two to fourteen days. COVID-19’s most common symptoms include fever, cough, fatigue, shortness of breath and loss of smell. More concerning symptoms include difficulty breathing, persistent chest pain, confusion, difficulty waking, and bluish skin. While the majority of cases result in mild-moderate symptoms, some progress to viral pneumonia, multi-organ failure, or cytokine storm. In these severe cases, infection can lead to death.

The virus is primarily spread between people during close contact, often via small droplets produced by coughing, sneezing, or talking. In experimental settings, the virus may survive on surfaces for up to 72 hours. It is most contagious during the first three days after the onset of symptoms, although spread may be possible before symptoms appear and in later stages of the disease. The standard method of early diagnosis is by real-time reverse transcription polymerase chain reaction (rRT-PCR) from a nasopharyngeal swab.

Currently, there is no vaccine or specific antiviral treatment approved for COVID-19. Management involves the treatment of symptoms, supportive care, isolation, and experimental measures.