A year in our understanding of COVID-19

The COVID-19 pandemic, caused by SARS-CoV-2, has resulted in more than a million deaths and tens of millions of infections globally. As we approach the first anniversary of its characterisation, it is timely to consider the developments, and persistent limitations, in our understanding of this pathogen. In this special edition of Clinical and Experimental Immunology we present five reviews and research papers on crucial aspects of COVID-19