A Look at Each Vaccine: Human Papillomavirus Vaccine
What is human papillomavirus?
How common is HPV?
Is HPV dangerous?
How do you catch HPV?
How can you avoid catching HPV?
Can't I avoid cervical cancer by simply getting routine Pap testing?
Can genital HPV infections be treated?
Is there a vaccine to prevent HPV?
Who should get the HPV vaccine?
Does the HPV vaccine work?
Is the HPV vaccine safe?
Do young women who get the HPV vaccine still need to get Pap tests?
Do women who have received the HPV vaccine still need to worry about sexually transmitted diseases?
Should boys get the HPV vaccine?
Can the HPV vaccine treat cervical cancer?
What is human papillomavirus?
Human papillomavirus (HPV) is a virus that infects the skin, genital area and lining of the cervix. There are many different types of papillomaviruses (about 100). Some types of papillomaviruses cause warts on the skin, some types cause warts in the anal and genital areas, and some types cause cervical cancer.
Many different HPV types cause cervical cancer. Two types (16 and 18) are the most common, accounting for about 70 percent of all cases of cervical cancer. Similarly, many types of HPV cause anal and genital warts; but only two types (6 and 11) account for about 90 percent of cases. One vaccine, GARDASIL®, contains types 6, 11, 16 and 18. Another HPV vaccine, CERVARIX®, contains types 16 and 18 only.
Other viruses can cause cancer, too. For example, hepatitis B virus causes liver cancer, AIDS virus can cause sarcoma (cancer of the skin), and Epstein-Barr virus (the virus that causes 'mono') can cause cancers of the head and neck and of the immune system. But these cancers can also be caused by other things. For example, alcohol can cause liver cancer, the sun can cause skin cancer, and poisons can cause cancer of the immune system.
Cervical cancer is unique in that it has only one cause: HPV.
How common is HPV?
HPV is the most common sexually transmitted disease in the United States and in the world. Twenty million Americans are currently infected with HPV and an additional 6 million Americans are infected every year. Half of those newly infected with HPV are between 15 and 24 years of age.
Is HPV dangerous?
Yes. Although most HPV infections typically resolve on their own, some persist. Every year in the United States about 25,000 women develop cervical cancer and 4,000 die from the disease. Cervical cancer is one of the most common causes of cancer in women. Worldwide, HPV kills about 250,000 women every year.
Babies can also be infected when they pass through the birth canal of a mother infected with HPV. Some of these children go on to develop a long-term infection of their windpipe that is occasionally fatal (this disease is called recurrent respiratory papillomatosis).
How do you catch HPV?
HPV is transmitted from one person to another by genital contact. Although this most often occurs during sexual intercourse, it can also occur during oral or anal sex or through genital-to-genital contact.
How can you avoid catching HPV?
Sometimes people can be infected with HPV and not know it. So HPV can be difficult to avoid. The best way to avoid genital infection with HPV is abstinence. You can also decrease your chance of getting HPV by having sex with only one other person who isn't infected with HPV. While condoms may also decrease the chance of getting HPV, they do not always work to prevent the spread of the infection. Because other than abstinence, none of these can completely protect someone from becoming infected or prevent the spread of this infection, the development of a vaccine was an important tool for preventing future generations from experiencing the devastation caused by HPV.
Can't I avoid cervical cancer by simply getting routine Pap testing?
No. At one time cervical cancer was the most common cause of cancer in the United States. One test changed that: the Papanicolaou (Pap) test. The Pap test is performed by scraping cells from the opening of the cervix and examining them under the microscope to see whether they have begun to show changes consistent with the early development of cancer (called pre-cancerous changes). Typically, the length of time from infection with HPV to development of cervical cancer is about 15-20 years. For this reason, although most HPV infections occur in teenagers and young adults, cervical cancer is more common in women in their 40s and 50s.
The Pap test is one of the most effective cancer screening tests available and has dramatically reduced the incidence of cervical cancer in the United States. But the test isn't perfect and not all women get tested as often as they should.
Can genital HPV infections be treated?
Highly effective and safe treatments for genital warts are not available. Also, current treatments are not designed to eradicate HPV infection.
Is there a vaccine to prevent HPV?
Yes. There are two HPV vaccines: GARDASIL and CERVARIX. Both are made in a similar fashion; however, GARDASIL protects against four types of HPV, and CERVARIX protects against two types of HPV.
In each case, the vaccine is made using a protein that resides on the surface of the virus. The protein is grown in the lab in yeast cells. Once the protein is grown, it assembles itself to look like the HPV virus; however, importantly, it does not contain HPV genetic material, so it can’t reproduce itself or cause illness.
Who should get the HPV vaccine?
The CDC recommended that all adolescents between 11 and 12 years of age receive the HPV vaccine. The vaccine can be given to girls as young as 9 years of age and is also recommended for all teenage and adult women between 13 and 26 years of age. The vaccine is given as a series of three shots; the second shot is given one to two months after the first; and the third shot is given six months after the first.
Boys between 9 and 18 years old can get the HPV vaccine (known as Gardasil) which protects against four types of HPV; however, the dosing schedule is the same as mentioned above for girls.
Does the HPV vaccine work?
Yes. The HPV vaccine was studied in about 30,000 girls and young adults between 9 and 26 years of age. Studies determined that the vaccine was 91 percent effective at preventing infections, 100 percent effective at preventing persistent infections, and 100 percent effective at preventing Pap smear changes that predict cervical cancer.
A recent study showed that, if given to all 12-year-old girls, an effective vaccine could prevent about 1,300 deaths every year in the United States.
Is the HPV vaccine safe?
Yes. Because the HPV vaccine is made using only the surface protein from the virus, it can't cause HPV and, therefore, can't cause cervical cancer. The vaccine may cause redness and tenderness at the site of injection. The vaccine may also cause a slight fever.
Safety networks have continued to monitor reactions to the HPV vaccine since its licensure. Despite concerns raised by the media and some citizen groups, no cause-effect links have been found between HPV vaccine and adverse events, including blood clots, allergic reactions, strokes, seizures, Guillain-Barre Syndrome, birth defects, miscarriages, or infant/fetal deaths. While fainting episodes following HPV vaccination have been reported, the rates have not been higher than those following receipt of other vaccines for teens. Because of the possibility of fainting, teens are recommended to remain at the office for about 15 minutes after getting immunized.
Do young women who get the HPV vaccine still need to get Pap tests?
Yes. The HPV vaccine prevents the types of HPV that cause about 70 percent of cervical cancers. Because the vaccine doesn't prevent all types of HPV that cause cancer, women still need to get routine Pap tests.
Do women who have received the HPV vaccine still need to worry about sexually transmitted diseases?
Yes. The HPV vaccine doesn't prevent other sexually transmitted diseases such as syphilis, gonorrhea, chlamydia and herpes virus, and the HPV vaccine doesn't prevent all of the dangerous types of HPV. Vaccinated women should still practice protective sexual behaviors (abstinence, monogamy or limiting the number of sexual partners, and condom use).
Should boys get the HPV vaccine?
Yes. Boys are recommended to get the HPV vaccine for two reasons: to protect themselves from anal and genital warts, and to protect their future sexual partners.
Can the HPV vaccine treat cervical cancer?
No. Unfortunately, therapeutic trials of HPV vaccine have shown that the vaccine doesn't cause a regression in Pap smear changes that precede cervical cancer.
Learn more about HPV and the vaccine»
Learn more about HPV and other STDs»
Reviewed by: Paul A. Offit, MD
Date: April 2012
Materials in this section are updated as new information becomes available. The Vaccine Education Center staff regularly reviews materials for accuracy.
You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family's personal health. You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel.
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