Yes, HPV (human papillomavirus) is a sexually transmitted infection. The CDC classifies it as one of the most common STIs, and roughly 85% of people will get an HPV infection at some point in their lifetime. It spreads primarily through vaginal or anal sex, but also through close skin-to-skin contact during sexual activity, which is why condoms reduce the risk without eliminating it entirely.
How HPV Spreads
HPV transmits through direct skin-to-skin contact, not through bodily fluids like some other STIs. This means it can pass between partners even when condoms are used, because the virus can live on skin that a condom doesn’t cover. That said, condoms still help significantly. In studies of men at the highest risk for exposure, consistent condom use cut the rate of new HPV infections by about 50%. Among women whose partners used condoms correctly every time, infection rates dropped by roughly 70%.
Most people who have HPV don’t know it. The virus rarely causes symptoms on its own, so it passes easily between sexual partners without either person realizing. This is a major reason it’s so widespread.
What HPV Does in the Body
Not all HPV infections are equal. There are many different types of the virus, and they fall into two broad categories: low-risk and high-risk.
Low-risk types, particularly types 6 and 11, cause genital warts. These are visible and sometimes uncomfortable, but they don’t lead to cancer.
High-risk types are the ones that matter most for long-term health. There are 12 of them (types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, and 59), and persistent infections with these strains can cause cellular changes that eventually develop into cancer. HPV is responsible for an estimated 39,300 cancer cases per year in the United States. The most common are cancers of the oropharynx (the back of the throat, including the base of the tongue and tonsils) at about 16,000 cases, cervical cancer at about 11,100 cases, and anal cancer at about 7,600 cases. HPV also contributes to cancers of the vulva, vagina, and penis, though in smaller numbers.
The important context here is that cancer is a rare outcome of a very common infection. The vast majority of HPV infections, between 80% and 90%, clear on their own within two years as the immune system suppresses the virus. It’s only when a high-risk type persists for years without clearing that the risk of cancer becomes real.
Screening and Detection
There is no general HPV test for all body sites, and there’s no approved HPV test for men. Screening focuses on the cervix, where the link between HPV and cancer is best understood and where early detection is most effective.
For people with a cervix aged 21 to 29, a Pap smear every three years is the standard recommendation. Starting at age 25, some guidelines allow for a high-risk HPV test alone as an alternative. For those aged 30 to 65, there are three options: a high-risk HPV test every five years, a Pap smear every three years, or both tests together every five years. The HPV test specifically looks for DNA from the high-risk strains most likely to cause cancer.
Genital warts, caused by low-risk types, are diagnosed visually. If you notice small bumps in the genital area, a healthcare provider can usually identify them on sight.
The HPV Vaccine
Vaccination is the most effective way to prevent HPV infection. The current vaccine (Gardasil 9) protects against nine HPV types: the seven high-risk types responsible for most HPV-related cancers (16, 18, 31, 33, 45, 52, and 58) and the two low-risk types that cause most genital warts (6 and 11).
The vaccine is recommended at age 11 or 12, though it can be given as early as 9. For anyone who missed it, catch-up vaccination is recommended through age 26. Adults between 27 and 45 who weren’t vaccinated earlier may still benefit, though the protection is less impactful since most people in that age range have already been exposed to at least some HPV types.
The number of doses depends on age. Children who start before their 15th birthday need only two doses, spaced 6 to 12 months apart. Those who start at 15 or older need three doses, given over about six months. The vaccine works best when given before any sexual activity begins, since it prevents infection but doesn’t treat existing ones.
Why HPV Is Different From Other STIs
HPV’s skin-to-skin transmission sets it apart from STIs that spread through semen, vaginal fluid, or blood. You can reduce your risk with condoms, but you can’t eliminate it the way you might with an STI that requires fluid exchange. This is also why HPV is so remarkably common: even people with few sexual partners frequently encounter it.
The other key difference is that HPV has no antiviral treatment. The body clears most infections on its own, and medical care focuses on managing the consequences (removing warts, monitoring cervical changes, treating precancerous cells) rather than the virus itself. If a high-risk HPV infection persists and causes abnormal cell growth on the cervix, those cells can be removed before they become cancerous. This is exactly what cervical screening is designed to catch.