Causes and Risk Factors of HPV

There are more than 100 human papillomavirus (HPV) viruses, some of which are more common than others. What causes HPV, regardless of the type, is the same: sexual, skin-to-skin contact with someone who is infected.

Some strains of HPV can lead to genital or anal warts and, in some cases, cancer. Not everyone develops symptoms of an HPV infection—either immediately or at all. This makes the spread of infection quite common.

HPV causes and risk factors
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Common Causes

The most common means of HPV transmission is sexual activity, including vaginal, anal, and oral sex. 

Even genital-on-genital rubbing can spread the virus. It's important that young people are informed about this, as they may be unaware that sexually transmitted infections can be passed without penetration.

Your risk of HPV significantly increases with your number of sex partners, although contact with just one partner who is infected can cause HPV.

While condoms provide the best means of protection short of abstinence, they can only do so if you use them consistently and correctly.

Most HPV infections (9 out of 10) go away by themselves within two years. It is during this time that you can pass the virus to others. Because HPV may not cause any symptoms, people are often unaware that they've been infected.

This further reinforces the need for condoms if you are sexually active and are not in a committed, monogamous relationship.

Doctors use numeric designations to name the various types of HPV. Since those designations are typically meaningless to non-medical professionals, physicians typically refer to a strain as being either a low-risk or high-risk HPV.

As you read on, you may feel encouraged learning that low-risk strains pose little health risk. But remember: All types of HPV are transmitted the same way.

Lifestyle and Health Risk Factors

While HPV can affect anyone, you are at increased risk if any of the following apply to you:

  • You engage in/have engaged in sex with several partners
  • You engage in unprotected sex or sexual contact
  • You are a man who has sex with men (MSM) 
  • You are transgender
  • You have HIV or another disease or condition that weakens your immune system

HPV Vaccine Can Prevent Infection

In addition to engaging in everyday HPV prevention strategies, you may consider speaking with your healthcare provider about Gardasil 9, the only HPV vaccine available in the United States. While 11- and 12-year-olds are the main vaccination groups, it may be given to older men and women in certain cases.

Low- and High-Risk Strains

While most HPV strains have the potential to cause genital warts, only 13 types are associated with cancer (primarily cervical, anal, penile, and throat cancer).

Because of this, scientists have broadly classified the strains by their potential to cause cancer as follows:

  • Low-risk strains are those that can cause genital warts but are otherwise harmless. HPV 6 and 11 are are responsible for around 90% of all genital warts. Genital warts caused by these strains rarely progress to cancer.
  • High-risk strains are those that can cause abnormal changes in cells (dysplasia) that can lead to cancer. Depending on the HPV strain you are exposed to, the dysplasia may be mild or severe. Among the high-risk strains, HPV 16 and 18 are associated with 70% of cervical cancers. HPV 16 accounts for more than 90% of anal cancers. Other high-risk types include HPV 31, 33, 35, 45, 52, 58, and 59.

Risk Factors for HPV-Related Cancer

While certain high-risk HPV strains are associated with certain cancers, scientists are still unsure why cancer will develop in some people with HPV and not others.

It is believed that genetics and family history play a part in this. At the same time, a person's environment, lifestyle, and general health (including past infections) can also contribute.

Beyond the HPV strain and location of the infection, there are other factors that can increase a person's risk of developing cancer from HPV. Among them:

  • Persistent HPV infection (lasting longer than 24 months)
  • HIV co-infection (and other forms of immune suppression)
  • Chlamydia and possibly herpes simplex virus infection
  • Oral contraceptives (increasing cervical cancer risk)
  • Having more than three full-term pregnancies (increasing cervical cancer risk)
  • Anal fistula (increasing anal cancer risk)
  • Being a man who has sex with men (increasing anal cancer risk)
  • Cigarette smoking (impacting all cancer types)

Of all of the possible risk factors, the delaying or complete avoidance of cancer screening is among the greatest ones. This includes routine Pap smears for those born female, as well as screenings for anal or genital problems in those born male.

Frequently Asked Questions

  • How does HPV cause cervical cancer?

    The human papillomaviruses associated with cervical cancer have two proteins, E6 and E7. These are able to "turn off" tumor suppressor genes in the DNA of cells. The role of these genes is to prevent abnormal cell growth, so cancer can develop when they're out of commission.

  • Can you get an HPV infection if you'e a virgin?

    Yes. You do not have to have sexual intercourse or penetrative sex to contract the human papillomavirus. It spreads easily through intimate activity of any kind, including oral sex or even close genital contact, as it thrives on the mucus membranes that line these structures. HPV doesn't live on the skin.

  • Can males get HPV?

    Yes. Males who contract the virus typically do not develop symptoms of infection or complications. However, certain strains of HPV can cause warts in males as well as cancer of the penis, anus, and the back of the throat (oropharynx cancer).

  • It is possible to get rid of the human papillomavirus once you're infected with it?

    Yes. The virus disappears from most people's bodies after a few months; around 90% of HPV infections clear up without treatment within two years. This is true even of the types that are high-risk for cervical and other cancers.

  • Is cervical cancer always caused by HPV infection?

    Virtually all cervical cancer is caused by HPV. That said, around 8% of cervical cancers are regarded as HPV-inactive, meaning the cancer doesn't show signs of the virus. HPV-inactive cervical cancer tends to affect women who are older. It has a relatively poor prognosis.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Cancer Society. HPV and cancer.

  2. Centers for Disease Control and Prevention. Human Papillomavirus (HPV). About HPV.

  3. Centers for Disease Control and Prevention. Human Papillomavirus (HPV). Genital HPV Infection - Fact Sheet.

  4. Centers for Disease Control and Prevention. HPV and Cancer. Basic information about HPV and cancer.

  5. Planned Parenthood. Human papillomavirus (HPV)

  6. World Health Organization. Human papillomavirus (HPV) and cervical cancer.

  7. Banister CE, Liu C, Pirisi L, et al. Identification and characterization of HPV-independent cervical cancersOncotarget. 2017;8(8):13375-13386. doi:10.18632/oncotarget.14533

  8. Centers for Disease Control and Prevention. Cancers associated with human papillomavirus.

Additional Reading

By Elizabeth Boskey, PhD
Elizabeth Boskey, PhD, MPH, CHES, is a social worker, adjunct lecturer, and expert writer in the field of sexually transmitted diseases.