H1N1: can a pandemic cycle be broken?

The influenza virus that caused the 2009 H1N1 swine-origin flu pandemic is antigenically similar to the one that caused the devastating 1918 pandemic. Over time, the human population became susceptible to a modified version of the 1918 pandemic H1N1 virus that had been archived in swine. Now, two papers, one in this issue of Science Translational Medicine and one in Science, shed mechanistic light on how glycosylation gave rise to seasonal human flu viruses that are immunologically distinct from their 1918 pandemic precursor and the 2009 pandemic strain. These findings suggest strategies to anticipate and prevent future pandemics.