What is HPV? Is it dangerous and does it go away?

HPV (human papillomavirus) is the name of a group of more than 200 related viruses ^{[1, 2]}. About 40 types can spread to the genital area, the mouth and the throat ^[8]. HPV is the most common infection passed on through sex ^[3]; almost everyone who has sex gets it at some point in their life ^[1]. So having HPV is not unusual.

The virus spreads through any close skin-to-skin contact during sex: vaginal, anal and oral sex ^{[2, 3]}. People who have the virus usually have no symptoms and may pass it on without knowing ^[3]. Condoms lower the chance of passing it on but do not prevent it completely, because the virus can be on skin that a condom does not cover ^{[2, 3]}.

HPV is silent and may show up on a test years later, so it is usually impossible to know when or from whom it came ^{[3, 6]}. Cancer itself is not contagious; what is passed on is the virus (Is cancer contagious?).

Most types of HPV cause no health problems ^[3]. Doctors divide them into two groups ^[2]:

• Low-risk types rarely cause cancer. Some of them, especially HPV 6 and 11, cause genital warts ^{[2, 10]}. The types that cause warts are different from the types that can cause cancer ^[10].
• High-risk types can cause cancer if they persist for a long time; they include HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 and 59 ^[2].

Not all high-risk types carry the same risk. In a large study of more than 11,000 women aged 30 to 65, the chance of developing severe precancer (or cancer) within 7 years was as follows for each type ^[4]:

A positive HPV test means the virus was found in the sample from your cervix; it does not mean you have cancer. Most people who have HPV never get cancer ^[1].

• HPV 16 or 18: these are the highest-risk types and together cause about 7 in 10 cervical cancers ^[5]. That is why a positive result for either needs earlier and closer follow-up ^[4].
• HPV 52 (and 58, 31, 33 and 35): these are also high-risk, but their risk is lower than that of HPV 16 ^[4]. In a worldwide study of more than 10,000 cervical cancers, HPV 52 and 58, together with 16, 18, 31, 33, 35 and 45, were the eight types that had caused about 9 in 10 of the cancers that contained HPV ^[5].

The next step depends on your Pap smear result, the type of virus and your earlier tests: sometimes just a repeat test after a year, sometimes a close look at the cervix with colposcopy. Each result is explained in Abnormal Pap smear or positive HPV test.

Yes, in most people. The immune system usually brings the virus under control within a year or two; this happens in 9 out of 10 people ^[1]. In the same large study, 8 in 10 high-risk infections that did not lead to precancer were no longer found on testing within 3 years ^[4]. In men, half of genital infections went away in under 8 months, and half of HPV 16 infections in about a year ^[7].

A negative test means the virus can no longer be found. Researchers now say this most likely means the body has brought the virus under control, not necessarily that it has left the body completely; sometimes an old virus shows up on a test again years later ^[6]. So if your HPV test has turned negative, that is good news; keep having cervical screening as scheduled ^[12].

Two things make it more likely that the virus stays: smoking and a weakened immune system, for example HIV or medicines that lower immunity ^{[1, 2]}. Not smoking, or stopping, lowers the chance that the infection persists ^[1].

There is still no medicine for the virus itself ^{[1, 3]}. But what HPV causes can be treated:

• Genital warts can be removed by a doctor with medicines or other methods; sometimes they go away on their own within a year ^{[3, 10]}. Treating warts probably does not clear the virus from the body ^[10].
• Cervical precancer is treated with simple methods: destroying the abnormal cells with heat or cold, or removing them with a thin electric wire loop ^[12].

That is why the most important step is regular cervical screening, so that any change in the cells is found and treated before it becomes cancer ^[12].

Men get HPV just as women do, and most have no symptoms ^[3]. In men, HPV can cause genital warts and sometimes cancer of the back of the throat, the anus or the penis ^{[1, 2]}. Worldwide, HPV causes about 70,000 cancers in men and 620,000 cancers in women each year ^[1].

Routine HPV testing is not recommended for men; the HPV test is for cervical cancer screening in women ^[3]. If your partner has tested positive for HPV, there is no test that can show whether you have HPV too ^[3]. If you notice a new wart, sore or lump in the genital area, mouth or throat, see a doctor ^[3].

Boys can have the HPV vaccine too: HPV vaccine: who should have it?

HPV, especially HPV 16, can cause cancer of the back of the throat (the tonsils and the base of the tongue) ^{[2, 9]}. In the United States about 7 in 10 cancers of the back of the throat are caused by HPV ^{[2, 8]}. The virus reaches the mouth and throat mainly through oral sex ^[8]. In one study, people who had had oral sex with 6 or more partners in their lifetime were more likely to have cancer of the back of the throat ^[9].

But it also helps to know ^[8]:

• Oral HPV infection goes away in most people within a year or two; it persists in only a few.
• It is more common in men: about 1 man in 10, compared with fewer than 1 woman in 25.
• It usually takes years to go from infection to throat cancer.

Symptoms that should be checked: a long-lasting sore throat, earache, hoarseness, swollen glands in the neck, pain when swallowing and unexplained weight loss ^[8]. Read more about this cancer and its treatment: HPV-related cancer of the tonsils and base of the tongue, Symptoms of throat cancer and Symptoms of mouth cancer.