Most patients with COVID-19 have mild to moderate symptoms. However, in a small proportion of patients, COVID-19 can lead to more severe illness, including death, particularly among those who are older or those who have chronic medical conditions. Symptoms include fever, cough and difficulty breathing. Symptoms appear within 14 days of being exposed to an infectious person. COVID-19 spreads primarily through respiratory droplets produced when an infected person coughs or sneezes.