HPV vaccines: are they the answer?

BACKGROUND The burden of human papillomavirus (HPV)-associated ano-genital disease is significant but the ability to generate HPV virus-like particles by the synthesis and self-assembly in vitro of the major virus coat protein L1 has transformed our prospects for preventing benign and malignant ano-genital disease caused by the common genital HPV types. SOURCES OF DATA Peer reviewed journals. AREAS OF AGREEMENT Two HPV L1 vaccines have been developed, a quadrivalent HPV 6/11/16/18, and a bivalent HPV 16/18 product. Both vaccines are very immunogenic and well tolerated. They have been shown in the various randomized Control trials to be very effective at preventing infection and premalignant disease related to the vaccine HPV genotypes in women who were DNA negative and sero negative for the vaccine HPV types at base line. The protection against disease generated by the vaccines persists for at least 5 years. HPV vaccines containing HPV 6/11 will reduce the incidence of genital warts by 80-90% in the medium term. The vaccines will reduce but not eliminate the risk of cervical cancer since at the present they only target two of the oncogenic genital types. Cervical cancer screening programmes will remain as important secondary interventions for cervical cancer even in vaccinated populations. AREAS OF CONTROVERSY The duration of protection remains unknown but there is evidence of good immune memory, it is possible that protection will be long lasting. The primary target group for cost effective immunization with HPV vaccines are peri-pubertal females. There may be benefit in vaccinating other groups (men, sexually active women of all ages) but the cost effectiveness of these interventions will need to be evaluated. In societies in which organized screening programmes are not available, HPV vaccines are probably the most realistic intervention against HPV-associated disease. AREAS TIMELY FOR DEVELOPING RESEARCH Second generation vaccines that offer protection against additional types, are thermostable and delivered by non-injection methods are an important area of investigation.