Human papillomavirus (HPV) is the most common sexually transmitted infection worldwide (Zhang et al. 2010). At least 75% of individuals will be infected, diagnosed or experience one of the many HPV strains in their sexual lifetime (Centers for Disease Control and Prevention 2010). The disease burden of STIs falls disproportionately on adolescents compared with older adults (Weinstock et al. 2004). Estimates suggest that even though young people aged 15–24 years old represent only 25% of the sexually experienced population, they acquire nearly half of all new sexually transmitted infections (STIs; Centers for Disease Control and Prevention 2009). Sexually active adolescents aged 15–19 years old are at a higher risk of acquiring STIs resulting from a combination of behavioural, biological and cultural influences (Kaiser Family Foundation 2011). The higher prevalence of STIs among adolescents may reflect multiple barriers to accessing quality STI prevention services, including perception of susceptibility and risk, parental acceptance of STI vaccinations, and concerns about confidentiality.
The US Food and Drug administration (FDA) approved a quadrivalent HPV vaccine against types 6, 11, 16 and 18 for the use in females aged 9–26 years old in 2006 (Merck and Co., Inc. 2009). With the potential to prevent the majority of genital wart exacerbations and invasive cervical, penile, anal, oral-throat cancers, the new HPV vaccine represents a remarkable public health achievement (Parkins & Bray 2006). Recently, the FDA approved the quadrivalent HPV vaccine for use in males aged 9–26 years old. The oncogenic HPV types (mainly 16 and 18) are responsible for cervical cancer in women and almost all anal cancers in men and women, HPV 16 and 18 also account for 40% of penile cancers in men as well as 25–35% of oral and neck cancers in men and women (Parkins & Bray 2006). Non-oncogenic HPV types 6 and 11 cause genital warts. It is necessary for the HPV vaccination to be administered prior to HPV exposure for it to offer full protection against HPV infections and its sequela. The ideal population to target for HPV vaccination is adolescents before their sexual debut.