COVID-19 is an infectious respiratory illness caused by the SARS-CoV-2 virus. The virus was first identified in Wuhan, China in December 2019 and has since spread to become a global pandemic.

The virus primarily spreads through respiratory droplets when an infected person coughs, sneezes, talks, or breathes. It can also spread by touching a surface contaminated with the virus and then touching the mouth, nose, or eyes. The incubation period for COVID-19 is typically 2-14 days, during which an infected person may be asymptomatic or have mild symptoms.

Symptoms of COVID-19 can range from mild to severe and include fever, cough, shortness of breath, fatigue, muscle or body aches, headache, loss of taste or smell, sore throat, congestion, and nausea or vomiting. In severe cases, COVID-19 can cause pneumonia, acute respiratory distress syndrome, and even death.

Prevention measures for COVID-19 include wearing masks, maintaining physical distance, washing hands frequently with soap and water, avoiding large gatherings, and getting vaccinated. Vaccines have been developed and authorized for emergency use to prevent COVID-19 infection and reduce the severity of illness in those who become infected.