Active immunity is a type of immunity that occurs when the body produces its own antibodies in response to an infection or vaccination. This process helps the immune system recognize and fight off specific pathogens, such as bacteria or viruses, if they invade the body again in the future. Vaccinations, like those for measles or influenza, are common ways to stimulate active immunity. When a person receives a vaccine, it introduces a harmless part of the pathogen, prompting the immune system to create antibodies. This prepares the body to respond effectively if exposed to the actual disease later on.