The corona virus disease or COVID-19 disease is caused by the SARS-CoV-2 virus, which primarily causes an acute respiratory infection that is spread as a droplet infection. The incubation period of the disease varies from 1 to 14 days, and the symptoms usually begin in 3 days from infection. The clinical picture may vary from almost asymptomatic to severe, and the symptoms may change as the disease progresses. Advanced age particularly in combination with a basic illness (e.g. severe cardiac disease) increases the risk of serious illness and death.
