Immunization, also known as vaccination, is a process that helps to protect individuals from infectious diseases by stimulating their immune system to recognize and fight off specific pathogens. It involves administering a vaccine, which is a preparation of either a weakened or inactivated form of a disease-causing agent, or a portion of the pathogen that can stimulate an immune response, to an individual. This exposure to the antigen in the vaccine triggers the body's immune system to produce a response, which includes the production of specific antibodies that can recognize and neutralize the pathogen if it is encountered in the future.

The benefits of immunization are many, including the prevention of diseases that can cause serious illness, disability, and even death. It is one of the most effective public health interventions available and has helped to eradicate or significantly reduce the incidence of many infectious diseases worldwide, such as polio, measles, mumps, rubella, and tetanus.

Immunization is typically administered as part of a routine schedule of vaccinations, starting in childhood and continuing through adulthood. The specific schedule and vaccines recommended may vary depending on an individual's age, health status, occupation, and travel plans.

It is important to note that while immunization is generally safe and effective, there can be some risks and side effects associated with vaccinations. These are usually minor and temporary, such as soreness or swelling at the injection site, mild fever, or a rash. Serious side effects are rare, but individuals should consult with their healthcare provider if they have any concerns or questions about vaccination.