Heterosexual transmission of HPV to male oral tract via oral/genital route indicated by partner data

The UK Joint Committee for Vaccination and Immunization (JCVI) has not so far decided to extend HPV vaccination to boys, but this possibility remains under consideration (Public Health England Guidance on HPV 2014-15). The potential benefit of protecting males from face and neck cancer will be an important consideration, both in the UK and in other countries contemplating this extension of HPV vaccination programs (STI/Conway & Adams).  Some have attributed the recent tripling in number of cases of these cancers to oral HPV, thus transforming what was formerly a smokers’ disease into an STI outcome.  A figure of 2,000.has been placed on the total of HPV attributable cases in UK males.  Such claims – and their public health policy implications – confer a new importance on research into the risk factors of oral HPV infection among young men.

A recently reported sub-study taking place in the framework of the Montreal based HPV Infection and Transmission among Couples through Heterosexual Activity (HITCH) cohort study claims to be the first to have established the association of oral infection in males with sexual behaviour, not just on the basis of their reported sexual behaviour, but through the collection of data from their partners (Dahlstrom & Franco).   The study administered questionnaires and tests to 222 young men and their partners at baseline and four-months.

Prevalence of oral HPV among male study participants was 7.2%.  Of these 28.6% (2) were found to have a partner with oral HPV infection, and 11.5% (15) to have a partner with genital infection.  The study also investigated type-specific HPV prevalences.  The prevalence among the young men of oral HPV16 (especially associated with head and neck cancer) was 2.3% (5); among the 33 men who had a partner with genital HPV, prevalence was (6.1%) (2/33).  In a rough and ready way, this study also establishes a correlation of oral HPV prevalence in males with frequency of oral sex (RR 1.47 as between rarely/sometimes having oral sex & rarely/never having oral sex).  The potential advance on previous studies is that this correlation is seen to hold only where the partner is genital HPV positive.

The importance of these findings is, first, to corroborate, on the basis of partner data, the conclusion drawn by earlier studies of the relation of oral HPV with reported oral sex, that there is indeed transmission of HPV from the female partner to the male partner’s oral tract, whether through oral or genital routes.  Second, the association of deep kissing with oral HPV infection seen in earlier studies would seem to be confirmed by the higher prevalence among men with oral HPV of female partners with oral HPV.  However, the alternative explanation of auto-inoculation, indicated in the study data by the high prevalence of genital HPV in self, cannot be excluded (STI/Hernandez & Ning).  Third, the possibility of oral sex as a route of transmission is suggested by the increased prevalence of oral HPV among men with a genital HPV partner, and its relationship to frequency of oral sex.