The quadrivalent human papillomavirus vaccine: potential factors in effectiveness

Cervical cancer, caused by human papillomavirus (HPV) infection, is the second most common female cancer in the world, causing over a quarter of a million deaths worldwide every year. The quadrivalent HPV vaccine (Gardasil) has the potential to significantly reduce morbidity and mortality associated with cervical disease. However, a variety of factors affect the vaccine's success, including exposure to HPV prior to vaccination, duration of protection provided by the vaccine, the in vivo interaction between HPV serotypes, and variation in HPV serotype prevalence worldwide. This article describes the pathophysiology of HPV infection, efficacy and safety of the quadrivalent HPV vaccine, factors that may influence the vaccine's effectiveness in reducing cervical cancer rates, and recommendations for maximizing this effectiveness.