Nonavalente

Nonavalente is an adjective used to describe something that has nine valences or nine targeted components. In a medical and vaccinology context, it refers to vaccines designed to protect against nine different serotypes or strains of a pathogen. The term fits within a broader terminology that includes bivalente, trivalente, tetravalente, pentavalente, and so on, indicating the breadth of coverage provided by a formulation.

The best-known use of the term in public health is the nonavalent human papillomavirus (HPV) vaccine, commonly referred to as the HPV 9-valent vaccine. This vaccine protects against nine HPV types (types 6, 11, 16, 18, 31, 33, 45, 52, and 58), expanding coverage compared with earlier bivalent and quadrivalent HPV vaccines. By broadening serotype coverage, the nonavalent HPV vaccine aims to reduce the incidence of cervical cancer and other HPV-associated diseases, in addition to preventing anogenital warts associated with certain types.

Beyond HPV, nonavalente formulations may exist or be proposed for other pathogens, describing vaccines or formulations that cover nine serotypes or antigens. In chemistry or molecular design, the term can also denote entities with nine coordination sites or valence positions. Overall, nonavalente conveys the concept of ninefold breadth or valence in a given context.