A new study claims to provide further evidence that oral human papillomavirus infections can be transmitted via oral-to-oral and oral-to-genital routes.

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Researchers found that oral HPV infection was common among men who had female partners with oral or genital HPV infection.

Human papillomavirus (HPV) is the most common sexually transmitted disease in the US, newly infecting 14 million Americans every year.

High-risk HPV infections - such as HPV 16 and HPV 18 - account for around 5% of cancers worldwide, including oropharyngeal cancers (cancers of the throat). It is estimated that each year, around 8,400 people are diagnosed with oropharyngeal cancers that may be caused by oral HPV infection.

But how people contract oral HPV is a subject that has been widely debated in medical research. Some studies have suggested that the virus can be contracted through oral sex with a person who has a genital HPV infection, while others have claimed the infection can be spread through engaging in open-mouthed kissing with a person infected with oral HPV. However, many studies have not found such associations.

Now, researchers from Canada say their new study - published in the journal Cancer Epidemiology, Biomarkers & Prevention - offers more evidence that HPV transmission can occur through oral-to-oral and oral-to-genital contact with an infected person.

Oral HPV common among men with infected female partners

Study leader Eduardo Franco, of the Department of Oncology at McGill University's Faculty of Medicine in Canada, and his team investigated HPV infection prevalence among 222 men and their female partners.

All participants were required to complete a questionnaire about their sexual history - including information about how often men gave oral sex to their female partner - and to provide oral and vaginal or penile/scrotal samples.

They found that 7.2% of men developed oral HPV. Of these, 28.6% had a female partner who had an oral HPV infection, while 11.5% had a female partner with a genital HPV infection. Smoking accounted for oral HPV infection in 12.2% of the men, while 17.9% of the infections occurred among men in non-monogamous relationships.

The researchers found that 2.3% of men who took part in the study were infected with HPV 16. Among the 33 men who had partners with a genital HPV 16 infection, 6.1% were infected themselves.

Furthermore, the team discovered that a man's risk of HPV increased the more they gave oral sex to their infected female partner; for every unit increase in oral sex frequency, a man's risk of becoming infected with the specific HPV type present in their female partner's genitals increased two-fold.

There were no HPV infections found among men who had a partner without oral or genital HPV, those who were in a monogamous relationship or those who had never smoked.

Commenting on the team's findings, Franco says:

"Understanding how HPV is transmitted is important because it will help us identify who is most at risk for HPV infection and how we can help them protect themselves and their partners.

Our work provides additional evidence that HPV is sexually transmitted to the oral tract through oral-to-oral and oral-to-genital contact."

Last year, Medical News Today reported on a study suggesting that oral HPV may be linked to poor oral health.

The researchers involved in that study, from the University of Texas Health Sciences Center, found that participants with gum disease were 51% more likely to develop oral HPV than those without the condition, while those with other dental problems had a 28% increased risk of oral HPV.