Background and aims: Recognition of human papillomavirus (HPV) as a necessary cause of cervical cancer (CC) led to new perspectives for its control and the demonstration of an effective primary prevention strategy through vaccination. We undertook this study to evaluate the safety, efficacy and immunogenicity of a quadrivalent HPV6/11/16/18 vaccine in Mexican women.
Methods: A total of 679 Mexican women between 18 and 23 years old participated in two Phase III double-blind, randomized, placebo-controlled clinical trials of a quadrivalent HPV 6/11/16/18 vaccine. Women were enrolled who tested negative for pregnancy and reported having four or less sexual partners during their lifetime. Vaccine or placebo was administered at day 1, month 2 and month 6.
Results: Among Mexican women who were naïve to the respective vaccine type at enrollment, the quadrivalent vaccine was highly efficacious, preventing 100% of HPV6/11/16/18-related cervical intraepithelial neoplasia grade 2/3, adenocarcinoma in situ, condyloma and vaginal intraepithelial neoplasia. Statistical significance was not reached for every endpoint due to the limited sample size. Vaccination was generally well tolerated and immunogenic.
Discussion: To widely administer the vaccine, collaborative efforts should be coordinated among public, private and local community sectors. In light of the scarce knowledge of many health professionals with respect to the primary prevention of CC, it will be necessary to educate health providers on the advantages and specific recommendations of HPV vaccines and secondary prevention. Decision making should be based on scientific evidence, allowing health professionals to provide an organized social response that supports the universal right to health.