COVID-19, which stands for coronavirus disease 2019, is a respiratory illness caused by a contagious virus named SARS-CoV-2. Contagious means it spreads from one person to another. In the case of COVID-19, transmission occurs when an infected person coughs or sneezes and the respiratory droplets land in someone else’s eyes, nose or mouth. Learn more about COVID-19 variant, prevention, symptoms, and testing for COVID-19.