a couple of articles on HPV and vaccine:
1. CDC reports: A new study looking at the prevalence of human papillomavirus (HPV) infections in girls and women before and after the introduction of the HPV vaccine shows a significant reduction in vaccine-type HPV in U.S. teens. The study, published in [the June issue of] The Journal of Infectious Diseases reveals that since the vaccine was introduced in 2006, vaccine-type HPV prevalence decreased 56 percent among female teenagers 14-19 years of age. this is in spite of the fact that <1/3 of eligible teenage females get the full vaccine series, suggesting perhaps that there is either herd immunity and/or there is functionally effective immunity with fewer than the full series of shots.
2. article in the lancet on association of oral HPV with oropharyngeal cancers (see http://dx.doi.org/10.1016/
S0140-6736(13)60809-0). oropharyngeal cancers disproportionately affect men (oral HPV infections 3x more common in men than women) and some are caused by oral HPV infection, esp with HPV 16 (this HPV type is associated with the rapid increase in oropharyngeal infections in some areas of the world, and one the main culprits for cervical ca in women). the lancet study looked at the incidence and natural history of oral HPV infections in men from Brazil, Mexico and the US. they checked oral samples every 6 months for up to 4 years. findings:
–1626 men aged 18-73 followed for median of 1 year.
–4.4% of men acquired an incident oral HPV infection within 1 year, 1.7% with oncogenic strain (13 strains including HPV 16 and 18), 0.6% with HPV16 (which was most common of the oncogenic strains).
–higher incidence in smokers, independent of sexual behaviors (though other studies have found that oral sex is associated with higher oral HPV infections, this study did not find that oral sex in the past 6 months or ever having oral sex was associated), more common in bisexual than heterosexual men.
–median duration of infection 7 months, with 8 of 18 oral HPV16 infections persisting for 2 or more study visits (20% lasting 12-18 months, but very low n)
so, oral HPV infections quite uncommon and mostly cleared within one year (as with vaginal infections in women). reinforces widespread use of vaccine. there was one study in costa rica, reported in PLOS One, which did find a decrease in oral HPV in women who were vaccinated. i do not know of any studies in men. but makes sense to immunize men and women, as recommended by CDC.
geoff