Covid-19 test and vaccine, conceptual illustration. SARS-CoV-2 (previously 2019-nCoV) was first identified in Wuhan, China, in December 2019. It is an enveloped RNA (ribonucleic acid) virus. The coronaviruses take their name from their crown (corona) of surface proteins, which are used to attach and penetrate their host cells. Covid-19 is a respiratory infection that can lead to fatal pneumonia. As of 26 March 2020, over 500,000 have been infected worldwide with over 20,000 deaths. Travel restrictions and quarantines have been put in place to slow the spread of the virus. Research is ongoing into a vaccine for the SARS-CoV-2 coronavirus, but it is not expected to be available before 2021.