HPV vaccine acceptance in male adolescents

Human papillomavirus (HPV) is one of the most common sexually transmitted infections worldwide [1]. It is so common that nearly all sexually active men and women will be exposed to it at some point in their lives. HPV can be passed from one person to another even when there are no visible signs and symptoms. Most people are able to clear the infection themselves with no lasting harm, but for some the virus persists and can lead to a number of health problems. HPV infection is well-recognised as a causative agent in cervical cancer, but it is also associated with other anogenital tumours, oropharyngeal cancers and genital warts, meaning that it also has serious health consequences in men and women [2]. Despite HPV’s impact on the health of both sexes, only the USA, Australia, Austria, Israel and two Canadian provinces currently recommend a gender neutral vaccination. Switzerland has recently made a recommendation that the vaccine should be ‘gender neutral’ and is currently considering offering the vaccine to both sexes. Despite this, there is substantial debate around the inclusion of men in HPV vaccination programmes. Many European countries do not include men and focus on achieving a high coverage in women to promote herd protection, that is, a reduction in the risk of infection in men due to reduced exposure as a result of vaccination in women. There is some emerging evidence that this is the case; an analysis of female only vaccination programmes in nine countries with high female vaccination rates found a reduction in the number of boys with genital warts of around one-third [3]. The incremental benefit of extending the vaccine to men is indeed highly dependent on coverage in women. With a low uptake in girls, the benefit of vaccinating boys is easily demonstrated. With more than 70% uptake in women, the gender neutral vaccine appears less cost-effective; however, a European study assessing the benefit of male vaccination in all carcinomas that have an established causal link with HPV demonstrated that the vaccination of 12-year-old boys and girls would be associated with substantial additional clinical benefits in terms of reduced incidence of HPV-related genital warts and carcinomas versus a girls only vaccination [4], this additional benefit was noted even with a high vaccine uptake. A female only vaccination strategy does however leave a number of men vulnerable to HPV infection, particularly men who have sex with other men (MSM) and men who have sex with unvaccinated women. A proposed solution could be to offer the vaccine to MSM at a sexual health clinic; however, for the HPV vaccine to be most effective, it should be given in adolescence, before exposure to HPV through sexual contact. Data on immunogenicity in men demonstrated that seroconversion and antibody titers are higher in male adolescents aged 9–15 years than male adolescents aged 16–26 years [5]. Most MSM are likely to have had multiple sexual partners with increased risk of HPV acquisition before they attend a sexual health clinic [6]. It is our opinion that the most practical and ethical solution to the problem is to offer HPV vaccination to both male and female adolescents. It is therefore imperative to understand the knowledge, awareness and attitudes of adolescent boys to HPV and HPV vaccination to ensure uptake is maximised and both boys and girls are protected against HPV-related cancers in the future. This is vital given that, for example, in the USA, where a gender neutral vaccine is offered, there is evidence to suggest that vaccine uptake in male adolescents is low; in 2012, only 20.8% boys aged 13–17 years received at least one dose, with only 6.8% receiving the full three-dose schedule [7]. In the past 5 years, there has been a proliferation of studies examining knowledge and awareness of HPV in adolescent boys (which is likely reflective of changes in