Antivalent refers to a condition in which a substance, such as an antibody or a vaccine, is designed to target or neutralize two different antigens or pathogens. This term is often used in immunology and vaccine development to describe products that can provide protection against multiple strains or types of a disease-causing organism. Antivalent vaccines can enhance the efficacy of immunization by offering broader protection compared to monovalent options, which target only one antigen.