Human papillomavirus (HPV) is the virus that causes cervical cancer in women and genital warts in men and women. The HPV vaccine effectively prevents infection with the two HPV types responsible for most cervical cancers and can also prevent genital warts. HPV vaccination is most effective during childhood or adolescence, but adults can also benefit from the HPV vaccine.Why Adults Should Get the HPV Vaccine
HPV infection is extremely common; most sexually active people will be infected with HPV at some point in life. HPV infection usually causes no symptoms, but cancause genital warts and anal cancer in both women and men.
In women, HPV infection can cause cells in the cervix to grow abnormally. In a small fraction of women, these HPV-induced changes will develop into cervical cancer. About 12,000 women are diagnosed with cervical cancer each year and about 4,000 women die from the condition.
The HPV vaccine prevents infection by the HPV types responsible for most cervical cancers. There are two available forms of the HPV vaccine:
- Cervarix: Prevents infection by HPV-16 and HPV-18. These two HPV types cause 70% of all cervical cancers. It is used for the prevention of cervical cancer and precancers.
- Gardasil: Prevents infection by HPV-16, HPV-18, and also HPV-6 and HPV-11, the two HPV types that cause 90% of genital warts. It is used to prevent cancers and precancers of the cervix, vulva, vagina, and anus.
Both HPV vaccines are extremely effective at preventing infection by the HPV types they cover. Getting the HPV vaccine reduces a woman’s risk of cervical cancer and precancerous growths substantially. Men cannot develop cervical cancer, but the HPV vaccine may prevent genital warts, anal cancer, and the spread of HPV to sexual partners. Only Gardasil is approved for use in men and boys 9 through 26 years of age.
The HPV vaccine does not treat or cure an HPV infection in women or men who are already infected by one of these HPV types.
When Should Adults Get the HPV Vaccine?
The CDC recommends that all women age 26 years and younger receive three doses of the HPV vaccine (Cervarix or Gardasil). The CDC recommends that all men age 21 years and younger receive three doses of the HPV vaccine (Gardasil only). It is an option for all men, but is recommended for men who have sex with men or who have a compromised immune system (including HIV) to receive the HPV vaccine through age 26 if not received earlier.
CDC guidelines recommend the three doses of the HPV vaccine should be given as follows:
- First dose: between ages 11 and 26
- Second dose: one to two months after the first dose
- Third dose: six months after the first dose
Some adults may have received doses of the HPV vaccine in childhood or adolescence. All three doses should be given to get the most protection from HPV infection. Re-vaccination in adulthood is recommended if the vaccination schedule was not completed.
Are There Any Adults Who Should Not Receive the HPV Vaccine?
Certain people should not get the HPV vaccine or should wait before getting it:
- Anyone who has had a life-threatening allergic reaction to a previous dose of the HPV vaccine
- Anyone who has had a previous life-threatening allergic reaction to an ingredient in the HPV vaccine
- Pregnant women
- Anyone with a moderate or severe illness; people who feel mildly ill may still receive the HPV vaccine.
The HPV vaccine is not known to be harmful to pregnant women or their babies. However, until more information is known, pregnant women are advised not to receive the HPV vaccine. Women who are breastfeeding can safely receive the HPV vaccine.
The HPV vaccine's safety and effectiveness have not yet been studied in adults older than age 26. Until that information is available, the HPV vaccine is not recommended for adults older than 26.
What Are the HPV Vaccine Ingredients?
The HPV vaccine contains no viruses and is not made from human papillomavirus. The active ingredients in the HPV vaccine are proteins that are similar to those found in the human papillomavirus. Genetically modified bacteria produce the proteins, which are then purified and mixed into a sterile, water-based solution.
What Are the Risks and Side Effects of the HPV Vaccine?
In clinical trials and in real-world use, the HPV vaccine appears to be very safe. More than 40 million doses of the vaccine -- mostly Gardasil, which was approved in 2006 -- have been given in the U.S. Cervarix was approved in 2009.
From 2006 to 2010, there were about 17,000 reports to the government of HPV vaccine side effects. About 15,500 of these were considered mild or moderate. The most common side effects of the HPV vaccine are minor:
- About one in 10 people will have a mild fever after the injection.
- About one person in 30 will get itching at the injection site.
- About one in 60 people will experience a moderate fever.
These symptoms go away quickly without treatment. Other mild-to-moderate side effects resulting from the HPV vaccine include:
- Nausea
- Fainting
- Headache
- Arm pain
Severe side effects, or adverse events, are uncommonly reported and have included:
- Blood clots
- Seizures
- Guillain-Barre syndrome
- Chronic fatigue syndrome
- Death
Government, academic, and other public health investigators could not identify the HPV vaccine as the cause of any severe adverse event. There were 56 deaths as of September 30, 2010, none of which could be directly tied to the HPV vaccine. The conclusion of public health investigators was that the HPV vaccine was unlikely to be the cause of these events. Such events occur at a certain rate in any group of tens of millions of people. The vaccination before each adverse event seemed to be a simple coincidence.
Post-licensure safety monitoring from June 2006 through March 2012 continues to show no new HPV vaccine safety concerns.
