In most people, the human papilloma virus (HPV) causes no symptoms and does not develop into pre-cancer or cancer. But there are some other facts about this sexually transmitted disease that may surprise you.
Anna Wald, M.D., M.P.H., director of the UW Virology Research Clinic, shares some little-known truths about HPV.
1. You are likely to get at least one type of human papilloma virus (HPV) in your lifetime.
HPV is the most common sexually transmitted infection in the United States. It is so common that most sexually-active men and women will get at least one type of HPV in their lifetime.
2. The type of HPV virus that causes genital warts is different from the type of HPV virus that causes cancer.
HPV is a group of more than 150 related viruses. Each type of HPV virus is given a number. HPV types are classified as either low risk or high risk based on whether they put a person at risk for cancer.
The HPV type that causes warts is low risk, meaning that it rarely develops into cancer. High-risk HPV does not cause warts, but can develop into cancer.
3. High-risk HPV types cause not only cervical cancer but also other cancers.
High-risk HPV types lead to cancers not only of the cervix but also of the vulva, vagina, penis, anus and the back of the throat, including the base of the tongue and tonsils.
4. You will clear most HPV infections on your own—even high-risk HPV infections—without any treatment.
“Most people acquire HPV shortly after becoming sexually active but have no symptoms," says Wald. Most people clear the infection—including the high-risk types—within two years, without ever knowing they had it.
A small proportion of women have an infection that becomes persistent. "It is in these women that you worry about cervical cancer,” says Wald.
5. Smoking makes HPV infection more difficult to clear.
Smoking increases your risk of developing a persistent HPV infection. Smoking is also linked to a higher risk for both cervical and vulvar cancers.
6. You can become infected with HPV without having sex.
HPV is not transmitted through bodily fluids such as semen or saliva, but through skin-to-skin contact. This happens most easily through sexual contact, such as vaginal, anal and oral sex. But it can also happen if HPV comes into contact with any mucous membrane (such as mouths, lips, anus and parts of the genitals) or with a break in your skin, such as a vaginal tear.
A condom, when used properly, does reduce the risk of HPV transmission. "It is not 100 percent but it does have some effect. This is because the HPV virus is found mostly in the penile skin so if you cover the shaft of the penis, then you are making some progress. But vaccines are much more effective, so certainly vaccinating people is the more effective way to prevent infection,” says Wald.
7. Partners of uncircumcised men have a higher risk of cervical cancer than partners of men who have been circumcised.
There is historical data that shows Jewish and Muslim women are less likely to get cervical cancer. “People thought that this fact must be related to male partner circumcision so they studied it," says Wald. "They found that indeed circumcision reduces the risk of HPV in men, and therefore also the risk of HPV transmission from men to women.”
8. There is screening for cervical cancer caused by HPV, but not for the other cancers caused by the virus.
“Women can at least be screened for cervical cancer,” says Wald, “But for men, there is no screening for anal cancer or the other cancers that might develop from HPV. That is one of the reasons that you should give the HPV vaccine to boys.”
9. The HPV vaccine may be effective against oral cancers as well as cervical cancer.
Results of a recent large-scale study were released by the American Society of Clinical Oncology in May 2017. These results show that in those who had received the HPV vaccine, the prevalence of oral HPV infections covered by the HPV vaccine was significantly lower. The most significant reduction was seen in men.
A reduction of oral HPV infections suggests that there might be a corresponding reduction in the oral cancers that develop from high-risk HPV over time. More studies will need to be done to determine if indeed the HPV vaccine prevents these cancers.
10. Women who develop cervical cancer from HPV have a higher risk of developing cancer of the vulva.
The same HPV types that are linked to cervical cancer are also linked to cancer of the vulva (AKA external female genitals). Therefore a woman who is infected with HPV or has a history of cervical dysplasia has a higher risk of developing vulvar cancer, too.
VIVA Clinical Trial
Anna Wald, MD, is currently conducting a study called the VIVA Clinical Trial (Vaccine to Interrupt Progression of Vulvar and Anal Neoplasia). The trial seeks to test if the HPV vaccine can help prevent recurrence of pre-cancerous lesions in people who have received treatment for a pre-cancerous anal or vulvar lesion and have not previously received the HPV vaccine.
For more information about the VIVA Trial, please contact the study manager, Sarah Taylor (206.667.4493 or 1.866.352.9525, email@example.com).