17 Things You Should Know About HPV

Human papillomavirus, or HPV, is actually a group of more than 100 viruses. These germs are incredibly common and can cause everything from the warts on your hands and feet to cervical cancer and sexually transmitted genital warts. Some types have no symptoms at all. (In fact, the more dangerous types are often symptomless, at least at first).

The good news is that most of the time, your immune system will eliminate these viruses with no help or treatment. However, the more you know about HPV prevention and testing the better chance you have to avoid the potentially life-threatening consequences of certain HPV strains.

If you're sexually active, there's a good chance that you'll be infected with HPV at some point in your lifetime. The U.S. Centers for Disease Control and Prevention (CDC) estimates that 80% of women will be infected before they are 50. About two-thirds of adolescent girls have HPV. Most of the time, these infections will go away on their own and there will be no long-term ill effects. In other cases, HPV can persist in the body causing cellular changes that can lead to cervical cancer or other problems.

And new ones are still being discovered. So far, scientists have identified more than 170 types of HPV. In July of 2013, researchers published findings on yet more strains. Fortunately, not all of these cause problems. About 40 are spread easily through vaginal, anal, and oral sex. At least 12 have been linked to cancer and, of these, two (HPV types 16 and 18) cause most HPV-related cancers.

HPV is most often associated with cancer in women, because it's found in 99% of cervical cancers. Obviously men don't get this type of cancer, but they can get infected with HPV. According to the CDC, almost all sexually active men will get HPV at some point and they get infected the same way as women: through sexual contact. Again, these infections go away most of the time, cleared by the body's immune system. But if HPV persists, it can cause cancer of the throat, penis, and anus in men.

Although warts in the genital area are much more common, HPV can also result in warts in the throat, a rare condition called recurrent respiratory papillomatosis (RRP). Sometimes these growths affect the voice, causing hoarseness, the most common symptom of RRP. They can also cause chronic coughing and breathing problems. Surgical removal is the most common treatment, although the warts often come back, leading to repeat surgery.

The growths associated with RRP are benign, but HPV can also cause throat cancer. In fact, HPV is the reason behind a recent increase in the number of throat cancers being seen in the U.S. By 2020, experts estimate, HPV may cause more throat cancers than cervical cancers. Symptoms can include a sore throat that just won't go away, hoarseness, and pain when swallowing. In 2013, actor Michael Douglas was reported to have said that his throat cancer was caused by HPV (contracted via oral sex) although he later clarified and said he was discussing risk factors in general, not his own specific case.

Mouth and throat cancers are relatively rare, but HPV is increasingly being recognized as a risk factor, possibly transmitted via oral sex. The risk is relatively low: Up to 80% of sexually active people aged 14 to 44 have had oral sex, but this type of cancer makes up only 3% of all cases. Smoking and alcohol are thought to be the main causes of throat cancer. However, "more and more we're realizing many head and neck cancers are caused by HPV, says Lois Ramondetta, MD, professor of medical gynecologic oncology at The University of Texas MD Anderson Cancer Center in Houston.

One recent study of 3,500 people found that those who said they had poor oral health had a 56% higher prevalence of HPV infection compared with those who thought their teeth and gums were in good shape. What was considered poor oral health? Gum disease, lost teeth, and using mouthwash to treat a dental problem within the past week. Scientists still have to tease out the relationship between HPV and oral health, but if you need another reason to brush your teeth regularly and visit the dentist, you've got one.

Actually, there are two already approved. Gardasil was licensed in 2006 and protects against HPV types 6 and 11 (which cause genital warts) and types 16 and 18 (which cause about 70% of all cervical cancers). Cervarix, approved in 2009, works only against types 16 and 18. Gardasil is the only vaccine to protect against precancers of the vulva, vagina, and anus. Dr. Ramondetta anticipates new vaccines may protect against more types of HPV.

Both HPV vaccines require three doses given at separate times, but new research suggests that one dose actually might be enough. In a 2013 study, the vaccine showed similar effectiveness four years after it was given, regardless of whether the women got one, two, or three doses. That's good news given that only 53% of girls ages 13 through 17 get an HPV shot and only about a third complete the series. However, it's best to stick to the recommended three.

Guidelines recommend that girls get the HPV vaccine when they are 11 or 12 years old, but it can be given as young as nine. The idea is that inoculating girls before they become sexually active will offer the best protection against HPV. The vaccine (either one) is also recommended for girls ages 13 through 26 who never got vaccinated or didn't get all three doses.

One of the HPV vaccines—Gardasil—is also approved for 11- and 12-year-old boys. This can protect them from developing cancers later in life. Although less common than other types, some 9,000 HPV-related cancers occur in men each year including cancers of the mouth, throat, penis, and anus. Giving the vaccine to boys can also protect girls indirectly by reducing transmission of HPV.

"There have been 150 million vaccine doses worldwide and multiple safety studies," says Dr. Ramondetta. "The vaccine is completely safe." There may be a little pain where the needle goes in and young girls sometimes faint, but the benefits outweigh the risks.

A study looking at 1,398 11- and 12-year-old girls—493 of whom had received the vaccine and 905 who had not—found no difference in sexual activity between the two groups. This suggests HPV vaccines don't encourage promiscuity, as some critics feared.

Thanks to the recent healthcare law changes, people covered under the Affordable Care Act get the HPV vaccine free as part of their preventive care services. The ruling went into effect January 1, 2011. Without insurance, the vaccines cost about $130 per dose.

Most women over age 26 have probably already been exposed to HPV, in which case the vaccine is useless. The good news is that routine cervical cancer screening—the Pap test—has been used for decades to pick up cervical cancer at early, treatable stages. The Pap test, which looks for abnormal changes in the cervix that can be caused by HPV, is recommended for all women 21 through 65. Women over 30 can also get an HPV test, which looks for the virus itself.

The Pap smear has been available since the 1950s and, in the past decade, five tests that look specifically for HPV have been approved. And things keep moving. "We're going to get better at knowing which people with HPV are more likely to get cancer," says Dr. Ramondetta. "It's a very exciting time."

Women should get Pap smears every three years beginning at age 21, whether or not they have had an HPV shot. The shots protect against some cervical-cancer causing viruses—specifically HPV 16 and 18—but not all of them. "HPV types 16 and 18 cause about 75% of all cervical cancers so we're still missing some," says Dr. Ramondetta. Women ages 30 to 65 should have Pap and HPV co-testing every five years or a Pap test every three years.

While many people assume men are more likely to transmit HPV to women, a new study suggests that is not so. Researchers reporting in the Journal of Infectious Diseases found that the risk of new infection was 60% higher in the male partner compared to the female partner. That's another argument for vaccinating males (although the study was funded in part by a vaccine manufacturer). "We saw such a large amount of infection occurring from females to males, that begs a questions about why we would not want to vaccinate males," says study lead author Alan G. Nyitray, PhD, assistant professor of epidemiology at The University of Texas School of Public Health at Houston.