User: How many people who contract COVID-19 end up experiencing symptoms and what symptoms might they experience?
Assistant: Approximately two-thirds of people who are infected with COVID-19 develop noticeable symptoms. Of those who develop symptoms noticeable enough to be classified as patients, most (81%) develop mild to moderate symptoms (up to mild pneumonia), while 14% develop severe symptoms (dyspnea, hypoxia, or more than 50% lung involvement on imaging), and 5% develop critical symptoms (respiratory failure, shock, or multiorgan dysfunction).