New concerns over the safety of the human papillomavirus (HPV) vaccine raised by GOP presidential candidate Michelle Bachman recently caused quite a media debate when she alleged the vaccine causes mental retardation. What is the truth behind HPV? Is the vaccine safe and effective? Here are the facts.
What is the HPV Vaccine?
Over 100 types of HPV exist, and while some kinds are high-risk, others have lower risk. High-risk HPV can lead to cervical cancer, and low-risk HPV can produce genital warts, but not cervical cancer. More than 30 forms of HPV are transmitted through sexual intercourse.
There are currently two vaccines approved for use by the Food and Drug Administration (FDA) to prevent HPV types known to cause most cervical cancers. These vaccines are Cervarix, made by pharmaceutical company GlaxoSmithKline and Gardasil, a product of Merck. In addition to preventing the two HPV types that cause up to 70 percent of cervical cancer cases, Gardasil has also been shown to prevent 90 percent of genital warts as well as anal, vulvar and vaginal cancers. Both vaccines, given in three shots over six months, are highly effective in preventing specific, but not all, HPV types.
What About the Types of HPV the Shots Don’t Protect Against?
The vaccines available today will not prevent about 30 percent of the cervical cancers diagnosed each year, according to the Centers of Disease Control and Prevention (CDC). For this reason, the CDC urges all women, beginning at age 21, to stay diligent in getting regular pap tests to screen for cervical cancer.
How Big of a Problem is HPV?
HPV is a group of the viruses that can cause cervical cancer. It is very common. About 6 million new genital HPV infections occur each year in the United States, and the majority of women and their partners will be exposed to HPV during their lifetimes, according to the Gynecological Cancer Foundation, a not-for-profit charitable organization dedicated to raising awareness about all forms of gynecologic cancer. The FDA said about 80 percent of women will be affected by HPV by age 50.
Many HPV infections occur without any symptoms, so you may not even know if you have the disease. Most cases will go away without any treatment over the course of a few years. However, HPV infections sometimes persist for many years, with or without causing detectable cell abnormalities. These infections can lead to cervical cancer. HPV is also associated with developing genital warts, cancers of the vulva, vagina, anus, and cancers of the head and neck, according to the National Cancer Institute (NCI).
How Many Women Contract Cervical Cancer?
Cervical cancer most often affects women during their childbearing years and can cause infertility and threaten their lives. In the U.S., cervical cancer affects about 12,000 women each year, and of those, one-third (4,000) will die from it. Worldwide, cervical cancer is the second most common cause of cancer deaths in women, according to NCI data. Having HPV vaccinations has the potential to reduce cervical cancer deaths around the world by as much as two-thirds, and to prevent anal cancer in males and females.
Who Should Get the Vaccines?
The FDA has approved Gardasil for use in females and males ages 9 to 26, and Cervarix is approved for use in females ages 10 to 25.
Why are the Vaccines Recommended for Children so Young?
Both Gardasil and Cervarix are proven to be effective only if given before HPV infection occurs, so it is recommended that they be used before a child becomes sexually active. Older females who may already be sexually active can also benefit from the vaccines, but to a lesser degree since these individuals may have already been exposed or infected with one or more HPV types. Sexually active women should have an informed discussion with their healthcare provider regarding their individual risks and potential benefits the vaccine may provide.
How Safe are the Vaccines?
Studies show the vaccines are extremely safe. Both HPV vaccines were studied in clinical trials before they were licensed. For Gardasil, more than 29,000 males and females participated in these trials. Cervarix was studied in several clinical trials performed all over the world on more than 30,0000 participating females. As of June 2011, about 35 million doses of Gardasil have been given.
As with all medications, some side effects do exist for both vaccines; however, 92 percent of Gardasil and 97 percent of Cervarix adverse side effects have been classified as “non-serious” by the Vaccine Adverse Event Reporting System (VAERS), the U.S. government agency that monitors adverse drug effects in the general population.
The most common side effects are redness and soreness in the arm where the shot is given. About one in 10 people will experience a mild fever and about one in 60 will get a moderate fever, according to the CDC. Headaches and dizziness have also been reported soon after the shot is given. These symptoms don’t last long and go away on their own.
Of the “serious adverse effects” reported to VAERS, few have been specifically blamed on the vaccines themselves. For example, Guillain-Barré Syndrome (GBS), a rare disorder that causes muscle weakness, has been reported in some people after receiving the vaccine. However, to date, there is no evidence that Gardasil increased the rate of GBS above that expected in the population, according to the CDC. Some people have reported blood clots in the heart, lungs and legs after getting Gardasil. Most of the reported cases involved people at risk of blood clots from use of birth control pills.
As of September 30, 2010, 56 vaccine-related deaths in the U.S. have been reported to VAERS. “Each of these deaths has been reviewed and there was not a common pattern to the deaths that would suggest they were caused by the vaccine. In cases where there was an autopsy, death certificate, or medical records, the cause of death was explained by factors other than the vaccine. Some reported causes of death received to date include illicit drug use, diabetes, viral illness, and heart failure,” the CDC reports.
Sources:
Human Papillomavirus (HPV) Vaccines Fact Sheet. National Cancer Institute. Institutes of Health Accessed online 23 Sept 2011 at http://www.cancer.gov/cancertopics/factsheet/prevention/HPV-vaccine
Centers for Disease Control and Prevention. Sexually Transmitted Diseases: HPV Vaccine Information For Young Women Fact Sheet Accessed online 23 Sept 2011 at http://www.cdc.gov/std/hpv/STDFact-HPV-vaccine-young-women.htm
The Gynecological Cancer Foundation, National Cervical Cancer Public Education Campaign. Cervical Cancer Facts Accessed online 23 Sept 2011 at http://www.cervicalcancercampaign.org/ccfacts/vaccine.html
The Centers for Disease Control and Prevention. FAQ About HPV Vaccine Safety. Accessed online 23 Sept 2011 at http://www.cdc.gov/vaccinesafety/Vaccines/HPV/hpv_faqs.html