COVID-19 is caused by a newly discovered coronavirus that was unknown before an outbreak in Wuhan, China in December 2019. The most common symptoms are fever, tiredness, and dry cough, and most people recover without needing special treatment. However, around 1 in 6 people become seriously ill, and older people and those with preexisting medical conditions are most at risk of severe illness. The disease spreads from person to person through respiratory droplets from coughs or exhales and by touching contaminated surfaces.