One of the most promising recent research developments in the fight against cancer has been the development and approval of a vaccine to fight the human papillomavirus (HPV) that causes cancer of the cervix in women.
“Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States,” state Richard E. Rupp, M.D., and Susan L. Rosenthal, Ph.D. in a recent clinical guide for pediatricians. “The vast majority of infections go unrecognized, but HPV is now implicated as a causative agent in more than 99 percent of cervical cancer cases.”
The Recommended Immunization Schedule for 2007 indicates that all adolescent girls should get a series of three HPV shots, preferably at age 11 to 12 years, to prevent cervical cancer and genital warts. The vaccine also is recommended for all females aged 13 to 26 years who have not yet been vaccinated.
Worldwide cervical cancer is the third most common type of cancer in women, although less common in the United States because of routine use of Pap smears to screen for early stages of the cancer. Cervical cancers start in the cells on the surface of the cervix. The development of cervical cancers very slow. It starts as a pre-cancerous condition called dysplasia. This pre-cancerous condition can be detected by a Pap smear and is 100 percent treatable. That is why it is so important for women to get Pap smears. Most women who are diagnosed with cervical cancer today have not had regular Pap smears or they have not followed up on abnormal results.
Undetected, pre-cancerous changes can develop into cervical cancer and spread to the bladder, intestines, lungs, and liver. It can take years for pre-cancerous changes to turn into cervical cancer. Patients with cervical cancer do not usually have problems until the cancer is advanced and has spread.
Although a number of observers have been concerned that some parents might be reluctant to accept the new HPV vaccines because of their connection to sexual activity, Rupp and Rosenthal note that research indicates otherwise.
“Once educated about HPV, the majority of parents are interested in these vaccines for their children,” they state. “Thus, if parents are provided with accurate information in a calm and reassuring way, there is unlikely to be resistance to immunizing their children with a highly effective vaccine against a potentially devastating disease.”
CDC HPV Vaccine Questions and Answers
Who Should Get This Vaccine?
The HPV vaccine is recommended for 11–12 year-old girls, and can be given to girls as young as 9. The vaccine is also recommended for 13–26 year-old girls/women who have not yet received or completed the vaccine series.
These recommendations have been proposed by the ACIP—a national group of experts that advises the Centers for Disease Control and Prevention (CDC) on vaccine issues. These recommendations are now being considered by CDC.
Why is the HPV vaccine recommended for such young girls?
Ideally, females should get the vaccine before they are sexually active. This is because the vaccine is most effective in girls/women who have not yet acquired any of the four HPV types covered by the vaccine. Girls/women who have not been infected with any of those four HPV types will get the full benefits of the vaccine.
Will sexually active females benefit from the vaccine?
Females who are sexually active may also benefi t from the vaccine. But they may get less benefit from the vaccine since they may have already acquired one or more HPV type(s) covered by the vaccine. Few young women are infected with all four of these HPV types. So they would still get protection from those types they have not acquired. Currently, there is no test available to tell if a girl/woman has had any or all of these four HPV types.
Why is the HPV vaccine only recommended for girls/women ages 9 to 26?
The vaccine has been widely tested in 9-to-26 year-old girls/women. But research on the vaccine’s safety and effectiveness has only recently begun with women older than 26 years of age. The FDA will consider licensing the vaccine for these women when there is research to show that 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 now being done to find out if the vaccine works to prevent HPV infection and disease in males. When more information is available, this vaccine may be licensed and recommended for boys/men as well.
Should pregnant women get the vaccine?
The vaccine is not recommended for pregnant women. So far, studies suggest that the vaccine has not caused health problems during pregnancy, nor has it caused health problems for the infant — but more research is still needed.
Efficacy of the HPV Vaccine
Studies have found the vaccine to be almost 100% effective in preventing diseases caused by the four HPV types covered by the vaccine — including pre-cancers of the cervix, vulva and vagina, and genital warts. The vaccine has mainly been studied in young women who had not been exposed to any of the four HPV types in the vaccine.
The vaccine was less effective in young women who had already been exposed to one of the HPV types covered by the vaccine. This vaccine does not treat existing HPV infections, genital warts, pre-cancers, or cancers.
How long does vaccine protection last? Will a booster shot be needed?
The length of vaccine protection (immunity) is usually not known when a vaccine is first introduced. So far, studies have followed women for five years and found that women are still protected. More research is being done to find out how long protection will last, and if a booster vaccine is needed years later.
What does the vaccine not protect against?
About 30% of cervical cancers will not be prevented by the vaccine, so it will be important for women to continue getting screened for cervical cancer (regular Pap tests). Also, the vaccine does not prevent about 10% of genital warts — nor will it prevent other sexually transmitted infections (STIs). So it will still be important for sexually active adults to reduce exposure to HPV and other STIs.
Will girls/women be protected against HPV and related diseases, even if they don’t get all three doses?
It is not yet known how much protection girls/women would get from receiving 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.
Safety of the HPV Vaccine
The FDA has licensed the HPV vaccine as safe and effective. This vaccine has been tested in over 11,000 females (ages 9–26 years) around the world. These studies have shown no serious side effects. The most common side effect is soreness at the injection site. CDC, working with the FDA, will continue to monitor the safety of the vaccine after it is in general use.
This article was featured in Healthy Children Magazine. To view the full issue, click here.