Human papillomavirus infection

Human papillomavirus infection, or HPV, is caused by a DNA virus belonging to the Papillomaviridae family. In most cases, the infection produces no symptoms and clears up on its own within two years—about 90% of infections do this. If the infection lingers, it can lead to warts or precancerous changes in cells. Depending on where these changes occur, they raise the risk of cancers in the cervix, vulva, vagina, penis, anus, mouth, tonsils, or throat. Almost all cervical cancer is tied to HPV, with two strains—HPV16 and HPV18—causing 70% of those cases. HPV16 alone is behind nearly 90% of HPV-linked oropharyngeal cancers (cancers of the tonsils and back of the throat, including the base of the tongue), but HPV attribution is lower for cancers of the oral cavity. Between 60% and 90% of the other cancers listed are also associated with HPV. Genital warts and a rare condition called laryngeal papillomatosis are commonly caused by HPV6 and HPV11.

More than 200 types of HPV have been identified, and a person can be infected with multiple types at once. The virus only affects humans. Over 40 types can be transmitted through sexual contact, infecting the genitals and anus. Risk factors for a persistent infection with these sexually transmitted types include having sex at an early age, having multiple sexual partners, smoking, and having a weakened immune system. These types spread mainly through direct skin-to-skin contact, most often during vaginal or anal sex. A mother can pass the infection to her baby during pregnancy. Evidence for indirect spread is limited, but some studies suggest it might be possible through contact with contaminated surfaces. Common hand sanitizers and disinfectants do not kill HPV, which raises the chance of transmission via non-living objects called fomites.

Vaccines are available to prevent the most common HPV types. Many public health organizations now screen for HPV directly, and early treatment improves outcomes. Nearly every sexually active person will get HPV at some point, making it the most common sexually transmitted infection worldwide.

High-risk HPV types are responsible for about 5% of all cancers globally and roughly 37,300 cancer cases each year in the United States. Cervical cancer is one of the most common cancers worldwide, with an estimated 604,000 new cases and 342,000 deaths in 2020.