The STI Files: Human Papillomavirus (HPV)

HPV⁠ – the human papillomavirus – is the group of viruses that cause all types of warts. Warts are growths in the skin that are the same color as the surrounding skin and can be flat, lumpy, or cauliflower-like. All warts are caused by different types of HPV, though not all strains of HPV cause warts.

There are about 100 known strains of HPV and not all of them are sexually transmitted. The warts people sometimes get on their hands and feet, for example, are spread by skin contact or contact with surfaces like locker room floors.

When we talk about HPV as an STI⁠ , we’re talking about the specific strains of the virus that are transmitted during oral, anal, and genital sex⁠ . The strains of HPV that are sexually transmitted only cause infection⁠ in mucus membranes – like in the mouth and throat, rectum⁠ , genitals⁠ , and urethra⁠ . So, having common warts on your hand or plantar warts on your feet is not the same as having sexually transmitted HPV.

Sexually transmitted strains of HPV are classified as either “low-risk” or “high-risk.” An infection with a low-risk strain of HPV can cause genital or anal warts, which might not be fun to have but are not a danger to your health. Infection with high-risk strains of HPV is usually asymptomatic but can eventually cause cancer, and this is the main type of HPV we want to test for and prevent.

How common is it?

HPV is extremely common. The CDC estimates that in the United States, about 79 million people (about one in four) are infected with a sexually transmitted strain of HPV. Without vaccination, almost every sexually active⁠ person in the U.S. will be infected with HPV at some point in their life. And since the HPV vaccines focus on strains that cause cancer, even with the vaccine most sexually active folks will get infected with some type of HPV.

How do people get HPV?

HPV is spread through skin contact and can be transmitted during oral, vaginal/frontal, anal, and manual sex⁠ , including through sharing sex⁠ toys. Because HPV is transmitted by skin-to-skin contact, it can spread even if there is no exposure to body fluids like semen⁠ or blood.

The parts of the body that can be infected with HPV include the mouth and throat, the anus⁠ and rectum, and the genitals. HPV in the genitals can be external (like on the penis⁠ or vulva⁠ ) or internal (like in the urethra, cervix⁠ , or vagina⁠ ).

HPV causes a localized infection, so if one part of your body is infected with HPV, that does not mean you have HPV in other parts of your body. In other words, having HPV in your throat does not automatically mean you have HPV in your genitals. However, multiple parts of the body can be infected with HPV and you can be infected with multiple strains at the same time.

What happens when you get HPV?

Not everyone with HPV has symptoms and most people with HPV don’t know they have it.

When someone with HPV does have symptoms, they might notice clusters of small, cauliflower-like growths on or around their anus or genitals. If the warts are inside of the rectum, urethra, or internal genitals, they usually go unnoticed. These warts are usually painless and will usually disappear on their own within two years.

Since high-risk strains of HPV do not cause warts, you will not know if you are infected unless you get tested. Most high-risk strains of HPV also go away on their own, but in a small percentage of people, the infection will become long-term and can eventually cause cancer.

High-risk strains of HPV can cause cancer in the genitals, in the mouth and throat, and in the anus and rectum. Anyone – regardless of their gender⁠ assigned at birth – can get cancer from HPV. Almost all cases of cervical and anal cancer are caused by HPV and aside from tobacco use, HPV is the main cause of oral and throat cancers.

How can I get tested?

HPV is not routinely tested for because almost everyone who is sexually active has HPV and HPV infection usually resolves on its own. What people do get screened for regularly is signs of cancer caused by high-risk types of HPV.

This test is called a pap smear⁠ . A pap smear is a lab test that does not look for HPV itself, but for a condition called dysplasia (a change in the shape of cells in the rectum or cervix) that is sometimes caused by high-risk strains of HPV. Dysplasia is an early warning sign of cancer that can be treated to prevent cancer from occurring.

There are two types of pap smears: anal paps and cervical paps. Both tests involve a swab (either of the rectum or the cervix), which is then examined under a microscope. When a provider gives a pap smear, the provider will also use a speculum to examine the rectum or cervix for warts and for visible warning signs of cancer. Again, although “warning signs of cancer” might sound scary, we’re talking about early signs that can be treated to prevent cancer. The guidelines for cervical and anal pap smears are different.

Cervical paps:

If you have a cervix, you should get a pap smear every three years after you turn 21. If you have an abnormal pap, you’ll probably be asked to start getting pap smears more often (usually yearly), at least until you consistently have normal pap smear results again. This test is a cervical cancer screening, not an HPV test – a “normal” result does not mean you do not have HPV. It just means no cancer warning signs were found.

People with cervixes might need additional testing depending on their age and pap smear results. There is an HPV test that is used for detecting HPV in the cervix (that is, the test looks for the virus itself), but this test is not a routine STI screen: it is only used in people who have had an abnormal pap smear or in people over the age of 30. There are no tests for finding HPV in the penis, vulva, vagina, anus, rectum, mouth, or throat.

Anal paps:

People of all genders who are HIV⁠ -positive should get an anal pap smear every year. This pap smear is a cancer screening, not a test that looks for HPV. There is not yet a solid guideline for how often HIV-negative folks should get tested, but HPV of the anus and rectum is very common in men who have sex with men. Some clinicians are starting to recommend routine anal paps for men (cis and trans) who have sex with men. There are no solid guidelines around who needs this test and how often, but if you have anal sex⁠ , it’s a good idea to talk to your sexual⁠ health provider about anal cancer screenings – depending on your age and sexual history, they might recommend routine anal paps.

Pap smears only check for signs of cancer in the cervix and rectum. Signs of HPV-related cancer in other regions – like the penis, vagina, and throat – can be caught by routine physical exams.

So pap smears look for tissue changes caused by high-risk HPV. What about low-risk HPV, which causes warts? There are no routine screenings related to low-risk HPV, but if you have symptoms that look like genital warts⁠ , a medical provider can diagnose HPV based on a physical exam. If you notice a new growth or lump that’s out⁠ of the ordinary for you, it’s a good idea to get it checked out by a medical provider whether you think it’s a wart or not, since skin changes can be caused by a lot of different medical conditions.

How is HPV treated?

Most folks with HPV do not need treatment, but if you have symptoms, a provider might recommend treatment.

Warts are not dangerous and if left untreated, they will eventually go away on their own. However, if you have warts and want to get rid of them, a medical provider can remove the warts by freezinglaser surgery, or applying tiny drops of acid to the warts. These procedures are done with local anesthetic and are not major surgery. Removing the warts can reduce (but not eliminate) your risk of spreading HPV to other people but it does not cure HPV.

If you have cervical or anal dysplasia (often referred to as an “abnormal pap”), it can be treated to prevent cancer. Cervical dysplasia is treated by using freezing or surgery to remove the abnormal tissue. Anal dysplasia can be treated using acid, lasers, or surgery. As with having warts removed, these procedures involve local anesthetic and are not major surgery.

Is HPV curable?

There is no cure for HPV but around 90 percent of people clear the infection on their own within two years. Unfortunately, there is no test that can tell you whether or not you’ve cleared the infection. If you’ve ever had genital warts or been told that you have HPV, your safest bet is to assume that you can spread it to other people, especially for the first two years after diagnosis.

Can it affect fertility⁠ ?

HPV does not cause infertility but if someone develops cancer, the cancer treatment itself can reduce fertility regardless of someone’s gender or the type of cancer. Cervical cancer might require surgery (like removal of the uterus⁠ ) that would prevent someone from carrying a pregnancy⁠ .

Can it cause death?

Genital warts are not life-threatening. HPV can only cause death if the infection leads to cancer.

How can we prevent HPV?

The best prevention we have against high-risk HPV is vaccination. The current vaccines for HPV protect against two, four, or nine different strains of the virus, which usually consist of the most common strains that cause cancer. People of all genders should be vaccinated against HPV. Ideally, you want to do this before you have any kind of sex with someone else (anal, vaginal, oral, or manual), but the HPV vaccine is still provided to young people regardless of whether they’ve had sex.

If you haven’t had the vaccine yet, you should get it even if you’ve been sexually active, because the vaccine can still protect you from strains of HPV you haven’t been exposed to yet. The HPV vaccine is almost 100 percent effective at preventing genital warts and infections with cancerous strains of HPV. There aren’t a lot of cancers that have a prevention strategy that works so well, so that’s a pretty big deal!

If you’ve been vaccinated, it is still possible to get warts from the strains of HPV that the vaccine does not protect against (the main purpose of the vaccine is to protect us from the high-risk strains of HPV that cause cancer). So, the protection from the vaccine works best if it’s backed-up with barriers.

There are a few important things to know about barriers and HPV prevention. HPV cannot pass through barriers – including condoms, insertive condoms, dental dams, and latex or nitrile gloves – but since HPV spreads by skin-to-skin contact, you can still get HPV on areas of skin that are not covered by a barrier. Condoms reduce the risk of HPV in the cervix by about 70 percent.

Unfortunately, there are no studies looking at condom⁠ use and other sites of HPV infection, but it’s reasonable to assume that using barriers correctly and consistently reduces, but does not eliminate, your risk of getting HPV (and even though they aren’t perfect at preventing HPV, barriers do a great job at preventing HIV, syphilis⁠ , chlamydia⁠ , and gonorrhea⁠ , so they’re still worth using!).

In addition to getting vaccinated and using barriers, routine pap smears are an important part of prevention (check out the section on testing above to learn more). Although pap smears do not prevent HPV, they are an important part of screening for and preventing cancer.

About age and the HPV vaccine

How young you need to be to get the HPV vaccine depends on where you live. In the United States, the HPV vaccine is only covered by insurance for people 26 and younger. The reason for the age limit has to do with money – the vaccine provides maximum protection to people who have not been exposed to a lot of different HPV strains, so it’s most cost-effective for insurance companies to only cover the vaccine for younger folks. Because HPV is so common, it’s assumed that most older folks have already been exposed to the strains that the vaccine protects against.

If you are older than 26, live in the United States, and still want to get the vaccine, you might be able to find a medical provider who will prescribe it to you (especially if you have not been sexually active yet, or have only begun having sex recently). Unfortunately, the vaccine probably won’t be covered by your insurance and you’ll probably have to pay out-of-pocket (about $200 per dose for the three dose series for a total of $600). Keep in mind that many sexual health clinics have a policy of not giving the vaccine to older people, so you might have to visit a private medical provider. This plus the out-of-pocket cost are obviously major barriers to a lot of folks.

Other countries have different age limits (in the UK, the vaccine is only covered until age 18 while in Canada it is covered until age 45) and some countries have approved the vaccine for different age ranges in different genders.

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