HPV vaccination in boys and men

Original Article:  bit.ly/1DQd94w

Infection with one of a subset of mucosal high risk Human papilloma virus (HPV), principally 16 and 18, is the cause of almost all cervical cancers in women, it is the major aetiological agent in squamous cell carcinoma of the anus, tonsil and base of tongue and a significant contributor to squamous cell carcinoma of the vulva, vagina, penis, larynx and head and neck.1 Altogether HPV is estimated to be the causal agent in 5% of all human cancers with HPV16 by far and away the major player. The contribution to the cancer burden is very significant but the disease burden of the “benign” or low risk HPVs – mainly 6 and 11 – should not be underestimated. Genital warts are the commonest viral sexually transmitted disease with a lifetime risk of acquisition of 10% representing a huge disease burden in men and women.2

HPV vaccines

There are two commercial prophylactic HPV vaccines that are licensed globally. These are Cervarix®, a bivalent product from Glaxo Smith Kline targeting HPV 16 and 18, and Gardasil® a quadrivalent product from MSDMerck that targets HPV 6,11,16 and 18. These vaccines are highly efficacious and national HPV immunisation programmes for girls and women have been recommended in more than 68 countries with national funding in 52. The UK has had a national HPV immunisation programme since 2008. This is a school based-programme with Year 8 (12-13 year old) girls as the ongoing cohort. In September 2014 a revised two-dose schedule dose – one at the beginning of vaccination and a second dose at 12 months – was implemented for the 12-13 year old cohort. A three-dose schedule remains in place for all girls and women 14 years and older. The UK programme is highly successful with coverage in 2012-13 of 86% for all three doses. The UK programme is restricted to females and, indeed, only three countries – USA, Australia and Austria – have funded programmes for boys and men.

Male vaccination

Gender-neutral vaccination is a controversial issue. If the reduction in female cancer is the only outcome to be considered then male vaccination provides only a small added benefit in the rate of disease reduction since, with a sexually transmitted infection (STI), immunising one gender at high coverage should with time block transmission and engender herd protection3. However, as in women, men develop HPV-attributable cancers of the anus, the oral cavity and the oropharynx and they have an equivalent burden to women of genital warts.

Anal carcinoma is a rare cancer but the incidence worldwide is increasing.4 Women have a higher incidence than men in age groups greater than 50, but men dominate the 20-49 year age group and this incidence is rising. Rates of anal cancer are highest in men who have sex with men (MSM), 37/100,000 and is even higher in HIV infected MSM at 131/100,000).5 Oropharyngeal squamous cell carcinomas (OSCC) associated with HPV have increased dramatically in men and women in developed countries over the past two to three decades6. In the USA, incidence of HPV OSCC is higher in men than women, as is the prevalence of oral HPV infection and it is projected that in the US the annual number of HPV-positive OSCC will surpass that of cervical cancers by the year 2020.7 Trials with the quadrivalent vaccine Gardasil have shown efficacy against infection and disease in men who have sex with women (MSW) and MSM, preventing 6/11 genital warts8 and 6/11/16/18 anal intraepithelial neoplasia9 respectively.

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