Advantages and disadvantages of current prophylactic vaccines against HPV

Abstract

Persistent infections with human papillomavirus (HPV) types of the alpha-papillomavirus genus that form the so-called high-risk (HR) group constitute the major risk for developing cancer of the uterine cervix, with nearly 500,000 new cases every year worldwide and approximately 250,000 deaths. Infections with low-risk (LR) types are usually associated with development of genital warts. Asymptomatic infections with both HR and LR types constitute the leading sexually transmitted disease, with approximately 8-12% of all sexually active women infected at a given time. Two commercial vaccines against HPV (Gardasil and Cervarix) are currently in the market in many countries worldwide. Both are produced with recombinant technologies, consist of self-assembled virus-like particles, the so-called VLPs, and have shown high immunogenicity. More important, they have been found to be highly efficient in preventing persistent infections and lesions not only from the uterine cervix, but also from the anus, vagina, and vulva. Unfortunately, vaccines are very expensive and unaffordable for many public health initiatives in developing countries. They include two types involved in cancer development (types 16 and 18); therefore, we can only expect a partial protection against cancer (70/100), making it necessary to implement novel strategies to detect precursor lesions and cancer in the postvaccine era. Strategies that include education and organized screening programs with detection of persistent infections should be implemented in developing countries if a reduction of cancer of the uterine cervix is expected over the next years.