Respiratory syncytial virus (RSV) sends millions of children to the hospital each year with pneumonia and related severe diseases and more than 100,000 die. No vaccine exists. Using the sophisticated tools of structural biology, researchers last spring identified a region on an RSV surface protein that binds highly effective antibodies. Now they have upped the ante and engineered a version of that protein prominently features that region. When injected into animals, the designer protein triggered production of remarkably potent antibodies, shaking up the crowded field searching for that elusive vaccine.