Human Papillomavirus (HPV) Vaccination - Gardasil
Why is HPV vaccination important? — Human papillomavirus (HPV) is a virus that causes cervical cancer and genital warts. Persistent infection with certain types of HPV can lead to cancer of the cervix, which affects more than 10,000 American women every year. HPV can also cause cancers of the vulva, vagina, and anus, although these cancers are much less common than cervical cancer. HPV also causes cancers of the head and neck in men and women.
Three vaccines (Gardasil, Gardasil-9, and Cervarix) are available to prevent infection with multiple types of HPV known to cause cervical cancer. It is hoped that these vaccines will significantly reduce the number of women who develop cervical cancer and pre-cancer.
WHAT IS HPV? — Human papillomavirus (HPV) is a virus that is spread by skin-to-skin contact, including sexual intercourse (vaginal sex), oral sex, anal sex, or any other contact involving the genital area (eg, hand to genital contact). Condoms do not provide complete protection from HPV infection because condoms do not cover all exposed genital skin. People do not become infected with HPV by touching an object, such as a toilet seat.
The risk of HPV exposure increases with the number of sexual partners you have and the number of partners your partner has. It has been estimated that 75 to 80 percent of sexually active adults will acquire HPV infection before the age of 50. A majority of women and men become infected with HPV for the first time between ages 15 and 25 years. Most people who are infected with HPV have no signs or symptoms, and in most cases, the infection goes away within two years, often without treatment.
In 10 to 20 percent of women, however, the infection persists. In this situation, there is a greater chance of developing cervical pre-cancer and then cancer. However, it usually takes on average 20 to 25 years for an incident HPV infection to cause cervical cancer. Thus, regular testing is important in detecting cervical abnormalities early, before cancer develops.
Over 100 different types of HPV have been identified; more than 40 of these are known to infect the cervix and approximately 15 are known to cause cervical cancer. Researchers have labeled the HPV types as being high or low risk for causing cervical cancer.
●HPV types 6 and 11 can cause about 90 percent of genital warts. These types are low-risk because they do not cause cervical cancer.
●Types 16 and 18 are the high-risk types that cause most (about 70 percent) cases of cervical cancer. HPV types 31, 33, 45, 52, and 58 are also high-risk types, causing about 19 percent of cervical cancers.
There are three US Food and Drug-approved HPV vaccines available. Talk to your healthcare provider to determine which vaccine is best for you. The three vaccines protect against different types of HPV:
●Gardasil-9 helps to prevent infection with nine HPV types (6, 11, 16, 18, 31, 33, 45, 52, and 58).
●Gardasil helps to prevent infection with four HPV types (6, 11, 16, and 18).
●Cervarix helps to prevent infection with HPV types 16 and 18.
HPV VACCINE TIMING AND DOSE — Gardasil and Gardasil-9 are given by injection and require three doses; the first injection is followed by a second and third dose two and six months later, respectively.
Cervarix is also given by injection and requires three doses, although the schedule is slightly different; the first injection is followed by a second and third dose one and six months later, respectively.
The vaccine may still be effective if fewer than three doses are given or if a different vaccination schedule is used. If you miss a dose, talk to your healthcare provider about how many more doses you need.
Who should be vaccinated? — In the United States, HPV vaccination with any vaccine is recommended for all girls and women who are between ages 9 and 26 years. HPV vaccination with either Gardasil or Gardasil-9 is recommended for boys and men who are between ages 9 and 21 years and can be given up to 26 years of age.
With any HPV vaccine, you will have the greatest protection from HPV if you are vaccinated BEFORE becoming sexually active. The vaccine does not help to get rid of HPV infection or any cervical abnormality after it has occurred. However, if you are less than 26 years old and you have been sexually active, had genital warts, a positive HPV test, or an abnormal Pap smear, you may still obtain some (albeit smaller) benefit from the HPV vaccine.
How long am I protected? — Scientists do not know exactly how long the vaccine protects against HPV infection. Clinical trials show that it provides protection for at least eight years.
Do I still need a Pap smear? — You do not need to have a pelvic exam or test for cervical cancer (eg, Pap smear) before you have the HPV vaccine. Cervical cancer screening (Pap smear) is recommended to start at age 21.
However, getting the HPV vaccine does not mean that you can skip cervical cancer screening in the future, since the vaccine does not treat pre-existing infections. Other types of high-risk HPV, which are not prevented by the vaccine, can also cause cervical cancer.
HPV VACCINE SIDE EFFECTS AND PRECAUTIONS — The HPV vaccine may cause mild redness, tenderness, or swelling near the injection site. There is no thimerosal (a mercury derivative used as a preservative) in the HPV vaccine. There may be an increased risk of passing out after an injection of Gardasil and possibly Gardasil-9. However, there are no known long-term side effects of the HPV vaccine.
The vaccine is not currently recommended during pregnancy, although there are no known risks to a fetus if the vaccine is given.
Despite concerns about safety based on anecdotal reports, large studies have not confirmed major health risks of these vaccines. Most experts believe that the benefits of the vaccine outweigh its risks.
DOES THE VACCINE REALLY WORK? — Results from vaccine studies show that the HPV vaccine in women is very effective in preventing HPV infections and cervical pre-cancers caused by HPV types targeted by the vaccine. HPV vaccination of women has been shown to reduce the risk of genital warts in their male sexual partners. Studies also show that the HPV vaccine in men reduces the risk of developing genital warts and persistent HPV infection, which may decrease the spread of HPV to sexual partners.
OTHER SEXUALLY TRANSMITTED INFECTIONS — The HPV vaccine is not perfectly protective, meaning that some women will acquire an HPV infection despite having being vaccinated. In addition, the vaccine does not prevent other sexually transmitted infections (STIs), including human immunodeficiency virus (HIV), herpes, chlamydia, and gonorrhea.
It is important to practice safer sex to reduce the risk of all STIs. This includes using a male or female condom with every sexual act.
Content adapted from UpToDate Patient Information.