In this issue, we find out what a worst-case pandemic would actually look like, discover why cold chain reliability depends as much on technician behaviour as on equipment, and learn why immunobridging requires more than a statistical bridge to support vaccine licensure. "No pandemic waits for us to catch up." – Michael Osterholm, Director, Center for Infectious Disease Research and Policy, University of Minnesota, USA "Immunobridging is only as strong as the framework surrounding it." – Marion F Gruber, Vice President, Public Health and Regulatory Affairs, IAVI