Saint Louis University is ready to test a new version of a bird-flu vaccine. Researchers are rounding up about 400 adults who want to take part. An earlier study of 450 adults has shown it takes a couple of high-dose shots to make the immune system produce antibodies against the virus that leads to avian influenza. The new study will use the same vaccine but some additional compounds are being added to see if the new mixture triggers the immune system with lower doses or fewer shots.