What is the process called that involves injecting a weakened form of a pathogen to trigger an immune response?

Vaccination is the process specifically designed to introduce a weakened or inactivated form of a pathogen into the body with the intent of triggering an immune response. This immune response prepares the body to recognize and combat the actual pathogen if it is encountered in the future. By introducing the weakened form, the immune system produces antibodies and trains immune cells to respond more effectively, ultimately leading to immunity against the disease without causing illness.

While immunization is a broader term that encompasses the overall process of becoming immune, which can result from natural infection or vaccination, vaccination specifically refers to the method of delivering the weakened pathogen. Inoculation and prophylaxis relate to different concepts; inoculation can refer to introducing any substance into the body, not exclusively for the purpose of vaccination, and prophylaxis refers to preventive treatment, which can include vaccines but is not limited to them. Thus, vaccination is the most precise term for the process described in the question.