Quadrivalent human papillomavirus vaccine (Gardasil) available for boys

The 4vHPV vaccine will be made available to boys aged 12–13 years via a school-based immunisation program in 2013. Boys in Year 9 at school in 2013 will also be offered the 4vHPV in a catch-up program that will run for a further 2 years under the NIP.¹ The 4vHPV vaccine is administered as a three-dose schedule at 0, 2 and 6 months.

Boys who wish to be vaccinated and are not eligible to receive 4vHPV via the NIP will need to purchase the three-dose 4vHPV vaccine course via private prescription. It is important to note that older boys who are sexually active may have already been exposed to various HPV types, including HPV 6, 11, 16 and 18, and that immunisation with the 4vHPV vaccine will not afford protection against pre-existing HPV infection with any of these types.

The Pharmaceutical Benefits Advisory Committee rejected the first-time application for listing on the basis of an unacceptably high and uncertain cost-effectiveness analysis.^2,3

A subsequent application was accepted on the basis of acceptable cost-effectiveness after a price reduction and resolution of some areas of uncertainty.^4,5 In particular, the re-submission presented data from the 4vHPV clinical trial to support the claim that results from a subgroup, in which progression to anal cancers was examined in male subjects with higher-grade anal intraepithelial neoplasia (AIN), may be generalised to the proposed NIP male population.⁴

In 2011 about 70% of Australian girls aged 15 years had been vaccinated with the three-dose course.¹ However, men who have sex with men (MSM) receive little benefit from HPV vaccination of women and have a higher risk of HPV infection and HPV-related cancers.^6,7 An analysis of Australian HPV trends indicated that HPV 16 is the predominant type seen in HPV cancers and, along with HPV 18, accounts for most HPV-associated cancers in men.^7,8 Extending 4vHPV vaccination to HPV naïve boys will not only afford direct protection but may increase herd immunity and indirectly protect people who are not vaccinated.^1,6

Likewise fewer cases of genital warts (usually associated with HPV 6 and 11) have been reported in vaccinated females and this has been demonstrated to provide indirect protection to unvaccinated heterosexual males through herd immunity.⁹ A retrospective sentinel surveillance study showed a 59% reduction in the number of new cases of genital warts in females and a 28% reduction in age-matched, unvaccinated heterosexual males.⁹ Genital warts are also prevalent among MSM populations, so this population will also benefit from 4vHPV vaccination.⁹

The benefit of vaccination is reduced in people who are already infected with one or more of the vaccine types, although people positive to all four serotypes would represent only a small proportion of the sexually active population.¹⁰

The protective efficacy of the quadrivalent HPV vaccine is likely to be long lasting; available data indicate that efficacy persists for at least 3 years in males.⁶ Studies are ongoing to establish the duration of efficacy of the 4vHPV vaccine in both males and females and whether or not booster doses will be required in the future. In a phase II extension study in females, the efficacy of the 4vHPV vaccine against disease endpoints (i.e. cervical or genital disease due to HPV types 6, 11, 16 or 18) was shown to be 100% after 5 years.¹¹

Injection-site reactions and mild systemic reactions were the most common adverse effects in clinical trials of the 4vHPV vaccine in males (and females).¹²

The Australian adverse events database for the year 2011 showed a similar incidence of these common adverse events with headache, nausea and dizziness commonly reported. Syncope was also reported to have occurred in about 10% of 4vHPV vaccine recipients.¹³