human papillomavirus quadrivalent (types 16, 18, 31, 45) vaccine

The human papillomavirus quadrivalent (types 16, 18, 31, 45) vaccine is a recombinant vaccine containing virus-like particles (VLPs) derived from the L1 major capsid proteins of HPV types 16, 18, 31, and 45. It induces humoral immune responses, generating neutralizing antibodies that prevent infection by these high-risk HPV types, which are associated with cervical, vulvar, vaginal, anal, oropharyngeal, and head and neck cancers. Administered intramuscularly, it is indicated for active immunization in individuals aged 9-45 years to prevent HPV-related precancerous lesions and cancers caused by these specific types, though no exact commercial product matches this precise formulation and it may represent a developmental or hypothetical variant.