Strengthening the case for gender-neutral and the nonavalent HPV vaccine

PURPOSE

The purpose of this review is to highlight the benefits of gender-neutral and the nonavalent human papillomavirus vaccination. Human papillomavirus infection is the most commonly sexually transmitted disease and is known to cause several types of cancers, including cervical, vulvar, vaginal, penile, oropharyngeal, anal, and rectal. 5% of cancers every year are attributable to human papillomavirus infection, with cervical cancer the most common and oropharyngeal cancer estimated to surpass the incidence of cervical cancer by 2020.

METHODS

PubMed and MEDLINE were searched using the following search terms: [(human papillomavirus OR HPV) AND (vaccine OR vaccination)] AND [(gardasil OR gardasil9 OR cervarix OR quadrivalent OR nonavalent OR ninevalent) OR (gender neutral OR male)].

RESULTS

There are currently three different types of human papillomavirus vaccinations and range in cover from four to nine different strains known to cause human disease. Most countries currently only supply vaccination to females; however, recent data point towards both a personal benefit as well as a cost-effective population-based benefit with gender-neutral vaccination. Data from female vaccination only have shown the vaccine to be effective in preventing premalignant cervical lesions, and are believed to have the same effect for other human papillomavirus cancers. Male vaccination not only provides personal benefit but also has a "herd effect" for females by preventing the propagation of the virus.

CONCLUSION

Gender-neutral vaccination provides significant cost-effective benefits for preventing human papillomavirus-related diseases, and this effect is further enhanced by the use of the nonavalent vaccine.

HPV vaccines - A review of the first decade

Pre-adolescent girls (9-15years) have the option of receiving a two dose HPV vaccine series at either a six month or one year interval to provide protection from HPV 16, the most prevalent type associated with cervical cancers, as well as several other less prevalent types. This series of vaccinations is highly likely to protect her from HPV infection until she enters the routine screening program, whether that be primary HPV testing or a combination of HPV testing and cytology. The two dose program has been recommended by the World Health Organization (WHO) since 2015. For women 15years and older, the three dose vaccine schedule is still recommended. The past ten years of Gardasil use has provided evidence of reduced HPV 16/18 infections in countries where there has been high coverage. Gardasil9 has replaced Gardasil. Gardasil9 has the same rapid anti-HPV 18 and HPV45 titer loss as Gardasil did. Cervarix remains equivalent to Gardasil9 in the prevention of HPV infections and precancers of any HPV type; Cervarix also has demonstrated sustained high antibody titers for at least 10years. One dose of Cervarix provides protection against HPV 16/18 infection with robust antibody titers well above natural infection titers. This may offer the easiest and most cost effective vaccination program over time, especially in low and lower middle income countries. Cervical cancer screening must continue to control cancer incidence over the upcoming decades. Future studies of prophylactic HPV vaccines, as defined by the WHO, must demonstrate protection against six month type specific persistent infections, not actual cervical cancer precursor disease endpoints, such as cervical intraepithelial neoplasia grade 3 (CIN 3) or adenocarcinoma in situ (AIS). This simplifies and makes less expensive future comparative studies between existing and new generic vaccines.