Scientific American asked Namandjé Bumpus, a pharmacologist at Johns Hopkins Medicine in Baltimore, and Ashley Lauren St. John, an immunologist at Duke-NUS Medical School in Singapore to answer some of the biggest questions about the currently available COVID vaccines. Should you get an authorized COVID vaccine now if you are eligible? The U.S. Centers for Disease Control and Prevention has not suggested a minimum interval between recovering from COVID and getting vaccinated. Vaccine efficacy refers to how well it performs in a carefully controlled trial, whereas effectiveness describes its performance in the real world. For those with a history of severe allergic reactions or allergies to the vaccine ingredients, it would be best to discuss it with a doctor before getting the COVID vaccine.