on 2 March, Trevor Bedford, a molecular epidemiologist at the Fred Hutchinson Cancer Research Center in Seattle, delivered another stunning assessment. In a blog post, Bedford explained that genomic evidence strongly suggested a link between the state’s first case in January and the high school student diagnosed in late February. That meant the virus may have been spreading unnoticed for five weeks. Bedford and collaborators at the Institute for Disease Modelling in Bellevue, Washington, estimated that 570 people in the region had already been infected.