Pfizer’s new COVID-19 vaccine might get FDA emergency use authorization in a few weeks, and a small group of Americans might begin getting shots in December. Moderna’s vaccine might quickly follow. But even for those who can get vaccinated soon—potentially 20 million people in the U.S., out of a population of more than 320 million—life won’t be able to go back to normal yet. Even after you’ve been vaccinated, if you’re lucky enough to get a vaccine in the months that follow the initial rollout, you’ll still have to wear masks and practice social distancing. Pfizer’s study showed that its vaccine, made in partnership with the German company BioNTech, has 95% efficacy. But there’s still a risk: Scientists don’t yet have all of the necessary data to know exactly what it’s effective at preventing.