The COVID-19 vaccines work really well. But their protection goes down over time. Your body forgets some things that the vaccine taught it. Then, your body isn’t as good at fighting COVID-19. But a booster shot or third dose can help! A booster shot is another dose of the vaccine. It teaches your body again how to fight COVID-19. Immunocompromised people may not get as much protection from the first two doses. Their bodies might not learn as much from the vaccine. A third dose can give them more protection and teaches their bodies how to better fight off COVID-19. Everybody needs a reminder!