You must get both doses to be fully vaccinated against COVID-19. Experts are still working to understand how much protection the COVID-19 vaccine provides. More studies are needed to understand how new variants may affect the effectiveness of existing COVID-19 vaccines. It is possible that some people who get vaccinated could still get sick and spread the disease to other people. This also happens in people who get a flu vaccine. Many times, people who do get sick after getting a vaccine have a milder case. It is important to continue to wear your mask over your nose and mouth, practice social distancing (staying at least 6 feet apart), continue to frequently wash your hands and use hand sanitizer with at least 60% alcohol after getting vaccinated.