Vaccines and Preventable Diseases:
HPV Vaccine - Questions & Answers For The Public
About the Safety and Effectiveness of the Human Papillomavirus (HPV) Vaccine
June 28, 2007
Background
Gardasil® is the first vaccine developed to prevent cervical cancer and genital warts caused by human papillomavirus (HPV). In June 2006, Gardasil® was licensed by the Food and Drug Administration (FDA). The Centers for Disease Control and Prevention (CDC) and the FDA monitor the safety and effectiveness of the vaccine.
Questions & Answers
What is human papillomavirus (HPV)?
HPV is a common virus that is passed on through sexual contact. Most of the time HPV has no symptoms so people do not know they have it. There are many different strains or types of HPV. Some types can cause cervical cancer in women and can also cause other kinds of cancer in both men and women. Other types of HPV can cause genital warts in both males and females.
In most people, HPV goes away on its own and does not cause health problems. Experts do not know why HPV goes away in some cases, but not in others.
How common is HPV?
HPV is the most common sexually transmitted infection in the United States, with about 20 million people currently infected. Women have an 80 percent chance of getting HPV by the time they are 50. Every year in the U.S., about 6.2 million people get a new HPV infection. HPV is most common in young people who are in their late teens and early 20s.
How common is cervical cancer?
The American Cancer Society estimates that in 2007 more than 11,000 women will be diagnosed with cervical cancer and approximately 3,600 will die from it in the U.S.
What is the HPV vaccine?
The vaccine, Gardasil®, is the first vaccine developed to prevent cervical cancer and genital warts due to HPV. It works by protecting against the four types of HPV that most commonly cause these diseases. The vaccine is given in three doses. The vaccine is licensed by the FDA for girls and women ages 9 through 26 years.
Who should get the HPV vaccine?
Doctors recommend this vaccine for 11- and 12-year-old girls. The vaccine also can be given to girls and women ages 13 through 26 who did not get the vaccine when they were younger or who did not complete the vaccination series.
Ideally, girls/women should get this vaccine before their first sexual contact when they could be exposed to HPV. This is because the vaccine prevents disease in girls/women who have not previously acquired one or more types of HPV prevented by the vaccine. It does not work as well for those who were exposed to the virus before getting the vaccine.
Is the HPV vaccine effective?
This vaccine targets the types of HPV that most commonly cause cervical cancer and genital warts. This vaccine is highly effective in preventing these types of HPV in young women who have not been previously exposed to them. The vaccine will not treat existing HPV infections or existing diseases or conditions caused by HPV. The vaccine also will not protect against disease and infection caused by other HPV types not included in the vaccine.
Is the HPV vaccine safe?
The vaccine has been licensed as safe. Before it was approved by the FDA, the vaccine was studied in thousands of females 9 through 26 years of age in the United States and around the world. The most common side effect is soreness where the shot is given.
How does CDC monitor the safety of vaccines?
One tool that is used to monitor vaccine safety is the Vaccine Adverse Event Reporting System (VAERS). VAERS is a national reporting system that accepts and monitors reports of potential side effects following vaccination. CDC and FDA work together to closely monitor the safety of all U.S. vaccines.
CDC and FDA physicians and scientists review all reports of serious side effects reported to VAERS to identify potential new vaccine safety concerns that may need further study. It is important to know that reports of side effects after immunization are not conclusive proof that the side effect was caused by a vaccine. Some of the side effects reported to VAERS may occur by chance following vaccination. Factors such as the vaccine recipient’s medical history and other medications taken near the time of the vaccination must be reviewed to determine if they could have caused the side effect.
How many VAERS reports related to HPV vaccination have been received?
As of May 8, 2007, VAERS has received a total of 1,763 reports of potential side effects following HPV vaccination. The most common VAERS reports have been soreness where the shot was given, as was seen in the clinical trials before the vaccine was licensed. There also have been some cases of fainting after vaccination. This also has been found with other vaccines given to adolescents. Many people have a fainting episode at some point in their lives and there are many potential causes. The ACIP’s general recommendations for all vaccines suggest a 15-minute waiting period following vaccination.
Have any reports of serious events been received?
Of the total VAERS reports, 94 (5 percent) are defined as serious. They include 13 unconfirmed reports of Guillain-Barre syndrome (GBS), a neurological illness resulting in muscle weakness and sometimes in paralysis. It is important to know that some cases of GBS will occur by coincidence following vaccination but not because of vaccination.
There also have been four deaths reported among females who received the HPV vaccine: One involving a blood clot in the lungs (pulmonary embolism); one involving inflammation of the heart muscle due to influenza; one from a blood clot; and one from multiorgan system failure due to influenza infection unrelated to vaccination. Preliminary data indicate that the two women who died of blood clots were taking birth control pills, and blood clots are a known risk associated with birth control pills. All four deaths are being fully investigated but none appear to be caused by vaccination.
Should pregnant women receive the HPV vaccine?
The vaccine is not recommended for pregnant women. There has been only limited information about how safe the vaccine is for pregnant women and their unborn babies outside of the clinical trials. For now, pregnant women should wait to complete their pregnancy before getting the vaccine. If a woman finds out she is pregnant after she has started getting the vaccine series, she should wait until after her pregnancy is completed to finish the three-dose series. Most importantly, she should continue her routine prenatal care and enroll in the registry the vaccine manufacturer is compiling of pregnant women who have received the HPV vaccine.
The Gardasil pregnancy registry has been established to collect information on the pregnancy outcomes of women who inadvertently receive the vaccine during pregnancy. The data collected will be used to monitor any effects the vaccine might have on pregnancies, so it is important that all eligible patients be enrolled. Individual patient information remains confidential.
Are there other ways, besides the vaccine, to prevent HPV?
The surest way to prevent genital HPV is to avoid sexual contact. For persons who are sexually active, condoms may lower their chances of getting HPV, if used all the time and the right way. Condoms may lower a person’s chances of developing genital warts and cervical cancer. But HPV can infect areas that are not covered by a condom – so condoms may not fully protect against HPV.
Will girls/women be protected against HPV and related diseases, even if they don’t get all three doses of the vaccine?
The HPV vaccine is recommended as a three-dose vaccine. It is not yet known how much protection girls/women would get if they receive only one or two doses of the vaccine. For this reason, it is very important that girls/women get all three doses of the vaccine.
Will the girls/women who have been vaccinated still need a Pap test?
Yes, they will still need to see their healthcare provider for a Pap test. Regular Pap tests are recommended for all women starting within three years of when a girl/woman begins sexual activity or at age 21, whichever comes first. The vaccine will NOT provide protection against all types of HPV that cause cervical cancer, so women will still be at risk for some cancers.
Why is the vaccine only indicated for girls/women 9 through 26 years old?
The vaccine has been widely tested in 9 through 26 year old females. But research on how well the vaccine works in older women has just recently begun. The FDA may license the vaccine for these women when there is research to show it is safe and effective for them.
What about vaccinating boys?
We do not yet know if the vaccine is effective in boys or men. Studies are being done to find out if the vaccine is effective in males. When more information is available, this vaccine may be licensed and recommended for boys/men as well.
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Content last reviewed on June 28, 2007
Content Source: National Center for Immunization and Respiratory Diseases