Coloured 3D computed tomography (CT) scan (posterior view) and axial CT scan (top right) of human lungs affected by Covid-19 atypical pneumonia (red and orange areas). Covid-19 is a respiratory infection that can lead to fatal pneumonia. It is caused by the coronavirus SARS-CoV-2 (previously 2019-nCoV, model at right), which was first identified in Wuhan, China, in December 2019. As of mid April 2020, over 1.8 million have been infected worldwide with over 117,000 deaths. Social restrictions and infection control measures have been put in place to slow the spread of the virus.