Coronavirus disease 2019 (COVID‑19) is an infectious disease caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2). It was first identified in December 2019 in Wuhan, Hubei, China, and has resulted in an ongoing pandemic.
Common symptoms include fever, cough, fatigue, shortness of breath, and loss of smell and taste. While most people have mild symptoms, some people develop acute respiratory distress syndrome (ARDS) possibly precipitated by cytokine storm, multi-organ failure, septic shock, and blood clots. The time from exposure to onset of symptoms is typically around five days, but may range from two to fourteen days.
The virus is spread primarily via nose and mouth secretions including small droplets produced by coughing, sneezing, and talking. The droplets usually do not travel through air over long distances. However, those standing in close proximity may inhale these droplets and become infected. People may also become infected by touching a contaminated surface and then touching their face. The transmission may also occur through smaller droplets that are able to stay suspended in the air for longer periods of time in enclosed spaces. It is most contagious during the first three days after the onset of symptoms, although spread is possible before symptoms appear, and from people who do not show symptoms.