COVID-19 is a new respiratory disease, caused by a novel (or new) coronavirus that has not previously been seen in humans. Reported illnesses have ranged from mild symptoms to severe illness and death for confirmed COVID-19 cases. Coronaviruses are a large group of viruses; some cause illness in people and some occur in animals, including camels, civet cats and bats. Rarely, animal coronaviruses can evolve and infect people and then may spread between people.