Immunity, Heterologous

**Definition:** The immunological phenomenon by which exposure to some organisms or vaccines can profoundly alter the host's response to subsequent exposure to unrelated (heterologous) organisms or vaccines.

**Tree numbers:** - G12.450.418

**Synonyms:** - Off Target Effects of Vaccines - Non-Target Heterologous Effects of Vaccines - Non-Specific Effects of Vaccines - Heterologous Immunity - Heterologous Effects of Vaccine - Non-Specific Effects of Vaccine - Non-Target Heterologous Effects of Vaccine - Off Target Effects of Vaccine - Heterologous Effects of Vaccines - Non-Targeted Immunity