Andrej Spec is Assistant Professor, Infectious Disease, Section Chief, Transplant Infectious Disease, Division of Infectious Diseases, John T. Milliken Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri, USA Bethany Davies is Associate Professor, Brighton and Sussex Medical School, Falmer, Brighton, UK Jane O'Halloran is UCD Professor of Infectious Diseases, UCD Centre for Experimental Pathogen Host Research (CEPHR), University College Dublin, Dublin, Ireland.