Coloured computed tomography (CT) scan of human lungs (axial view) affected by Covid-19 pneumonia (blue clusters at left). Covid-19 is a respiratory infection that can lead to fatal pneumonia. It is caused by the coronavirus SARS-CoV-2 (previously 2019-nCoV), which was first identified in Wuhan, China, in December 2019. As of late April 2020, over 2.8 million have been infected worldwide with over 193,700 deaths. Social restrictions and infection control measures have been put in place to slow the spread of the virus.