Immunogenicity refers to the ability of a substance, such as a vaccine or pathogen, to provoke an immune response in the body. This response typically involves the activation of immune cells and the production of antibodies, which help to identify and neutralize foreign invaders. Factors influencing immunogenicity include the nature of the substance, its dosage, and the individual's immune system. Understanding immunogenicity is crucial in vaccine development, as it helps researchers determine how effectively a vaccine can protect against diseases. For example, the COVID-19 vaccine was designed to enhance immunogenicity, ensuring a strong immune response to the SARS-CoV-2 virus.