A QUADRIVALENT RECOMBINANT HUMAN PAPILLOMA VIRUS (HPV) VACCINE, PREPARED FROM PURIFIED VIRUS-LIKE PARTICLES OF THE CAPSID PROTEIN L1, IS LICENSED IN THE USA TO PREVENT GENITAL WARTS, CERVICAL CANCER, AND OTHER PRE-CANCEROUS LESIONS CAUSED BY HPV TYPES 6, 11, 16, AND 18. FURTHER VACCINES ARE UNDER INVESTIGATION FOR THE TREATMENT OR PROPHYLAXIS OF GENITAL WARTS AND SEVERAL MALIGNANT NEOPLASMS.