Bad news: you can get HPV from oral sex. Worse news: you can get oral cancer from HPV.

open-mouthed teens

Most people have heard of the human papilloma virus, HPV. It is the virus that causes genital warts in men and women. It’s gotten a lot of attention because it appears to be the cause of cervical cancer in women, cancer of female reproductive organs.

Many people have heard about Gardasil, the new vaccine designed to protect women against HPV, and therefore against cervical cancer. The vaccine appears to be very promising in women and studies are underway to determine if it is equally effective in men.

Few people are aware that HPV can infect the mouth through oral sex. A new study published in the March issue of the Journal of Infectious Disease (Oral Sexual Behaviors Associated with Prevalent Oral HPV Infection) is a preliminary study, but it suggests some very disturbing possibilities. Men who engaged in oral sex were more likely to have human papilloma virus infections of the mouth. More disturbing is that the study raises the possibility that oral HPV can be transmitted from person to person by open-mouthed kissing. Most disturbing of all, oral HPV may lead to oral cancer in the same way that cervical HPV leads to cervical cancer.

According to the study:

… [O]ral HPV infection was more strongly associated with the number of recent oral sex and open-mouthed kissing partners than with recent vaginal sex partners. In multivariate analysis, 6 [or more] recent oral sex or open-mouthed kissing partners … significantly elevated the odds of oral HPV infection developing …

To further evaluate the independent effect of open-mouthed kissing, a subset analysis was performed for the 59 college-aged men who reported no history of performing oral sex. Among these men, oral HPV infection was significantly more common among those with 10 [or more] lifetime and those with 5 [or more] recent open-mouthed kissing partners.

In other words, HPV infection was more common in men who had more oral sex partners, and more open-mouthed kissing partners. This suggests that, as expected, performing oral sex increases the risk of an oral HPV infection. The unexpected finding is that increased open-mouth kissing may also transmit the infection. That is supported by the fact that a few men who had never performed oral sex had oral HPV infections. It raises the possibility that they had contracted oral HPV from open-mouth kissing of partners who had performed oral sex on others.

What are the effects of oral HPV infection. In the short term, there appear to be few effects. In the long term, oral HPV infection is associated with the development of mouth and throat cancers. Tobacco use is another cause of mouth and throat cancer. It is unclear whether the two causes are independent or whether they interact.

The studies are preliminary, and involve only small groups, so the results must be interpreted with caution. Nonetheless, they are very worrisome. HPV genital infection is extremely common, particularly among young men and women. We know that genital HPV infection can cause cancer of the cervix in women. Similarly, HPV appears to cause at least some mouth and throat cancers. If a common genital infection can be easily transmitted to the mouth through oral sex, and then passed along through kissing, the potential for widespread infection and serious consequences is high.

Fortunately, the Gardasil vaccine appears to have great promise in preventing cervical cancer, and there is reason to believe that it could be effective in preventing oral cancers caused by HPV. Let us hope that is the case. Otherwise, we could be facing the grim prospect of an epidemic of cancer caused by oral sex, and spread by kissing.