Immunizations, also known as vaccines, are medical treatments that help protect individuals from infectious diseases. They work by introducing a small, harmless part of a virus or bacteria into the body, prompting the immune system to recognize and fight it. This process helps the body build immunity, so if exposed to the actual disease later, it can respond effectively. Vaccines are important for public health as they can prevent outbreaks of diseases like measles, polio, and influenza. Many immunizations are given during childhood, but some may be needed throughout life. Vaccination not only protects the individual but also helps create herd immunity, reducing the spread of diseases in the community.