Immunization is the process of administering a vaccine to stimulate the immune system to develop immunity to a specific disease. This helps protect individuals from contracting the disease in the future. Immunization is a crucial public health intervention that has led to the eradication of deadly diseases such as smallpox and the near-elimination of others like polio. Vaccines are typically administered through injections, oral drops, or nasal sprays, and are recommended for people of all ages to prevent the spread of infectious diseases and maintain overall population health. Ongoing research in immunization focuses on the development of new vaccines, improving existing vaccines, increasing access to immunization services, and addressing vaccine hesitancy.