HPV and Cancer

How do you get HPV? You acquire Human Papilloma Virus (HPV) through direct skin to skin contact with an infected person, through vaginal, penile, oral, or anal sexual contact, even if a person has no warts. The more sexual partners you have, the more likely you are to be infected and develop cancers from it. These viruses cause virtually all cases of cervical cancer and many cancers of the skin, vagina, penis, anus, mouth, nose, head and neck. Using condoms helps reduce your chances of becoming infected, but does not offer complete protection. Six million North Americans are newly infected each year, Twenty million are infected now with HPV, and more than 80 percent of sexually-active men and women have been infected.

Types of HPV: More than 150 different HPV viruses have been found, and the ones most likely to cause cancers are types 16, 18, 52 and 59. They are also the ones that persist the longest, and are most likely to cause cancers and abnormal PAP smears.

Can I ever get rid of HPV? Doctors cannot cure HPV, they can only destroy the warts caused by these viruses with chemicals or remove them with surgery. Most infections appear to clear themselves without any treatment (Am J of Ob and Gyn, 2000;183(3): 561-567). DNA tests of HPV show that 70 percent of women clear HPV infections within one year, and only nine percent continue to be infected after two years (NEJM, 1998;338(7):423-428). A summary of several studies shows that 90 percent of HPV tests become negative in about two years. The current theory is that you become infected with HPV through sexual contact and it can disappear without treatment, as cultures fail to find it. We do not know if the virus really goes away, but we often cannot find it. However some people never clear the high-risk HPV types and it is the persistent infections that can lead to cancers (Trends in Microbiology, 2011(Jan);19(1):33-39). Each additional sexual exposure increases your chances of acquiring additional HPV viruses and the specific viruses that cause cancer. You can have several different HPV virus types at the same time. Infected people who continue to have the most sexual contacts are the ones most likely to continue to be infected with HPV, as each new exposure carries risk for a new infection.

How long does it take for the virus to become undetectable? The average time for a person who has acquired HPV to have the virus unavailable for culture is six months. However, those with high risk HPV 16 and 18 took an average of almost eight months for the virus to become non-detectable. Again, we do not know if it really goes away.

Does having the virus cause abnormal pap smears? Most women who are infected with HPV will not develop a positive PAP test.

Immunization: Immunization protects you from infection with the viruses in that vaccine. It does not protect you from the many viruses not in the vaccine. High risk HPV subtypes are associated with almost all cervical cancers. Available HPV vaccines contain high risk HPVs 16 and 18.