STI Deep Dive: HPV

The human papilloma virus, or HPV, is the most common STI. Roughly 14 million people get HPV each year, and nearly 80 million Americans are currently diagnosed with it. It is so common that most sexually active people who aren’t vaccinated against HPV will become infected at some point. About 85 out of 100 people who are sexually active have a chance of being infected with HPV. HPV can be transmitted through sex and through skin-to-skin contact, which includes genital to genital or mouth to genital contact. There are over 200 strains for HPV, most of which are asymptomatic. It is possible to be infected with more than one HPV strain at a time. Different strains of HPV cause warts on different areas of the body, including the feet, hands, and face.

More than 90% of all new HPV infections go away or become undetectable on their own within two years. It is currently unknown as to why some people’s immune systems can clear the HPV infection and some cannot. Some HPV infections can stay in the body and lead to complications, like genital warts. About 40 strains of HPV affect the genital area, but most of those don’t pose a serious health risk.Strains of HPV are identified by number and are sorted into low-risk and high-risk categories.

Most low-risk genital HPV strains don’t cause symptoms and become undetectable when the body builds immunity to the virus. These strains have no association with cancer, but can lead to genital warts, which can appear on the vulva, penis, cervix, vagina, scrotum, anus, mouth, and throat. Most of these warts are caused by two different strains of HPV, types 6 and 11. Some low-risk HPV strains can cause mild cervical dysplasia (abnormal, non-precancerous changes in the cells on the surface of the cervix).

Infection with a high-risk HPV strain can lead to more extensive cervical dysplasia and to certain types of cancer. There are at least 12 strains of HPV that are considered high-risk, but types 16 and 18 cause the majority of HPV-related cancers, about 70%. These cancers can affect the cervix, vagina, vulva, penis, anus, throat, tongue, and tonsils.

Gardasil-9 (9vHPV) is the vaccine distributed in the United States. It protects against nine types of HPV (6, 11, 16, 18, 31, 33, 45, 52 and 58). It is available to children as young as 9 years old. It is recommended that children ages 11–12 should get 2 doses of the HPV vaccine, given 6 to 12 months apart. Only 2 doses are needed if the first dose is given before the 15th birthday. If a person receives the…