Vaccines have been very successful in preventing disease in the United States. Diseases that used to kill thousands, like polio, whooping cough, and measles, almost don’t exist now. Immunizations reduce the number of deaths and other complications caused by diseases. Many adults don’t know that they still need to get vaccines and vaccine boosters. Some believe that the vaccines they got as children will protect them for the rest of their lives. The vaccines you need as an adult are based on your age, health conditions, lifestyle, places you travel, and vaccine history. You never outgrow the need for immunizations.