HPV Vaccine Therapy in Interrupting Progression in Patients With High-Grade Vulvar or Anal Lesions

OUTLINE: Patients are randomized to 1 of 2 arms. ARM I: Patients receive recombinant human papillomavirus nonavalent vaccine intramuscularly (IM) at baseline, 2 months, and 6 months. ARM II: Patients receive placebo IM at baseline, 2 months, and 6 months. After completion of study treatment, patients are followed up at months 7, 12, 18, 24, 36, and 42.