Illustration of the structure of the SARS-CoV-2 coronavirus. It is an enveloped RNA (ribonucleic acid, yellow) virus. Within the membrane (purple) are spike proteins (red), membrane proteins and envelope proteins. Spike proteins allow the virus to bind to the host cell. Membrane proteins and envelope proteins play a role in virus assembly. SARS-CoV-2 causes the respiratory infection Covid-19, which can lead to fatal pneumonia.