Cervarix is a prophylactic vaccine comprised of a mixture of virus-like particles derived from the L1 capsid proteins of human papillomavirus (HPV) types 16 and 18 formulated with the AS04 adjuvant system. It is administered by intramuscular injection as a three-dose vaccine regimen at 0, 1 and 6 months. The vaccine is indicated for the prevention of high-grade cervical intraepithelial neoplasia (CIN 2 and CIN 3) and cervical cancer causally related to HPV types 16 and 18. In randomized, double-blind, phase II or III trials in >19,000 women aged 15-25 years, the HPV 16/18 vaccine showed high efficacy in preventing CIN 2+ associated with HPV 16/18. Cross-protection against new incident or 6-month persistent HPV 45 or HPV 31 infection was also evident. Phase II follow-up was for at least 5.5 years, and the phase III interim analysis was at approximately 15 months after the first vaccine dose. In a bridging study, in adolescent girls aged 10-14 years, the HPV 16/18 vaccine induced twice the already high antibody titres as it did in young women (aged 15-25 years). The immune response in older women (aged 26-55 years) at 24 months in another study was >or= 8-fold higher than antibody levels reported in younger age groups. Anti-HPV 16/18 antibody responses were greater with an AS04-adjuvanted HPV 16/18 vaccine than with an aluminium salt-adjuvanted formulation. The HPV 16/18 vaccine was generally well tolerated and injection-site reactions were the most common vaccine-related adverse events reported.