A hundred days into the coronavirus disease (COVID-19) pandemic

Steffens, Ines

The virus causing COVID-19 was identified and announced on 7 January and by 10 January, sequences of five genomes had been shared, providing scientists around the world with a basis for development of diagnostic tests [8] . There was fast growing knowledge about several important parameters for understanding the spread of disease. A number of studies in various settings determined the basic reproductive number R 0 to be within the range of 2-3 [9, 10] ; the incubation period was determined as ranging from 1 to 14 days with an average of 5-6 days; transmission through droplets was established as the main mode of transmission; the clinical picture that emerged included a wide range from mild symptoms with fever, sore throat and cough to severe pneumonias with characteristic features on computed tomography scans; in Hubei, China, up to 13.8% of laboratory-confirmed patients had severe disease, 6.1% were critically ill and the case fatality rate among all COVID-19 cases was 2.3% [11] .