Human papillomavirus, also known as HPV, is the most common sexually transmitted disease in the United States and responsible for around five percent of cancers worldwide, most notably cervical and throat cancer. Although around 14 million Americans are infected with HPV each year, doctors are still not entirely sure of how it spreads. A new study has provided further evidence that HPV isn’t restricted to sexual intercourse and can also be spread via mouth-to-genital and mouth-to-mouth contact, with individuals who use tobacco being at the highest risk for infection.

Understanding HPV Transmission

In a new study, now published in the journal Cancer Epidemiology, Biomarkers, & Prevention, a team of Canadian researchers provide further evidence to unshroud the mystery surrounding the spread of HPV.

"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,” explained the study’s authors to Medical News Today.

The team investigated the prevalence of HPV among 222 men and their female partners. Each individual was asked to complete a questionnaire about their sexual history. This included questions such as how often men gave oral sex to their female partners. Both the male and female volunteers were asked to provide oral samples as well as vaginal or penile/scrotal samples.

Results showed that 7.2 percent of the men developed oral HPV. Of this percentage, 28.6 percent had a female partner who had an oral HPV infection and 11.6 percent had a female partner with a genital HPV infection. Of the men who partook in the study, 2.3 percent were infected with HPV 16, but of the 33 men who had partners with a genital HPV 16 infection, only 6.1 percent were actually infected themselves. These numbers led the researchers to conclude that when it came to possible routes for the virus’s transmission, a man’s chances of becoming infected with the virus double each time he gives oral sex to his infected female partner.

HPV And Tobacco

While the link between oral sex and the spread of HPV was notable, the researchers also found that using tobacco also increased an individual’s chances of becoming infected with the virus. Smoking accounted for oral HPV in 12.2 percent of the men, MNT reported. Scientists have previously noticed this link and believe it is due to tobacco’s erosive nature. 

“These results suggest that tobacco may make these infections less likely to clear, and therefore smokers may have a higher risk of eventually developing oropharyngeal cancers,” Dr. Gypsyamber D’Souza, an associate professor at Johns Hopkins Bloomberg School of Public Health, told Time. A separate study found that people who currently use tobacco had more cases of oral HPV16 than former users or those who had never used the drug.

Researchers believe that HPV needs a wound to enter the body, Medical New Today reported. While those who use tobacco are more likely to have openings inside of their mouths, a study from 2013 suspected that overall poor oral hygiene, such as mouth ulcers and chronic inflammation, also put individuals at an increased risk for this infection.

Source: Franco El, Dahlstrom KR, Burchell AN, et al. Sexual Transmission of Oral Human Papillomavirus Infection among Men. Cancer Epidemiology Biomarkers & Prevention. 2014