On June 8, 2006 the Food and Drug Administration (FDA) approved Gardasil, the world's first cancer vaccine. Gardasil is used to protect girls and women, ages 9 through 26, from the two types of human papillomavirus (HPV) infection that are responsible for most cervical cancer cases. It is not effective, however, against other types of HPV that cause approximately 30% of cervical cancers. For that reason, administration of the HPV vaccine needs to be combined with regular screening for cervical cancers (Pap smears) in order to detect cervical cancer in its early stages when treatment is most effective.

HPV is the name for a group of viruses that cause both cervical cancer and genital warts.¹ HPV exists in more than 120 forms. Although many types of HPV do not increase the risk of cancer, about 30 types of HPV spread through sexual contact greatly increase the risk of cancers around the anus and the genitals in both males and females. Of all the sexually-transmitted types of HPV, two types, 16 and 18, are responsible for approximately 70% of all cases of cervical cancer. Gardasil protects against infections caused by both of these types. The vaccine also provides immunity to HPV types 6 and 11 that have been identified as causing approximately 90% of all cases of genital warts, but do not cause cancer.¹

What makes HPV especially dangerous is that many of the approximately 6 million people who are infected with genital HPV each year in the United States have no symptoms and therefore do not even know that they are infected. Although most HPV infections are short-term, women with persistent infections are at higher risk for developing cervical cancer. Genital HPV infections cause more than 10,000 cases of cervical cancer per year.

Cervical cancer is the second most common cancer in women worldwide, killing approximately 288,000 women each year, and about 3,700 women in the U.S. Research shows that more than 90% of women who develop cervical cancer have had a genital HPV infection at some point in their lives. Public health officials in the U.S. encourage women to have a Pap smear at least every 3 years beginning at age 18, or once they become sexually active. Using Pap smears to detect cervical cancer or precancerous lesions has significantly decreased the number of deaths from cervical cancer. According to the Centers for Disease Control and Prevention (CDC), deaths from cervical cancer are more likely among women who are uninsured or underinsured. More than half of all U.S. women diagnosed with cervical cancer reported not having had a Pap smear in the last 3 years prior to diagnosis.²

All women will still need regular Pap smears, whether or not they are vaccinated with the HPV vaccine. Approximately 30% of cervical cancers are not linked to the HPV types 16 and 18 that the vaccine protects against. In addition, women who are beyond the age of vaccination or who have already been exposed to HPV will also continue to need regular Pap smears. It is important to note that cervical cancer has a long lag time between exposure to HPV and the onset of disease, so women may incorrectly assume they are no longer at risk because they are not sexually active or have been in a monogamous relationship.

The vaccine data thus far are short-term, so it is unknown whether the immunity to HPV will last for more than the 4.5 years observed in clinical trials.^{3, 4} Patients may need a booster shot for longer-lasting HPV prevention. This is a concern, because the initial vaccine must be administered three times over a six-month period, and can cost as much as $400 for the 3 shot series. The relatively high cost of the vaccine and the unknown cost of booster shots raise concerns that uninsured women and less affluent women will not be able to afford to protect themselves from HPV and cervical cancer.⁵

National Recommendations

On June 29, 2006, the CDC's Advisory Committee on Immunization Practices recommended that the vaccine be given routinely to all girls ages 11 and 12. The U.S. Department of Health and Human Services accepted the Committee's recommendation and most health insurance providers are expected to add Gardasil as a coverage option for consumers.⁶ However, it is estimated that 11 to 15% of all children with health insurance are under plans that do not include coverage for routine vaccinations.^{7, 8} The CDC Committee has also recommended that the HPV vaccine be included in the Vaccines for Children Program, the federal program which provides free vaccinations to children 18 years of age and under. Children who are uninsured, on Medicaid, protected by the Indian Health Services Act, or underinsured patients at Federally Qualified Health Centers and Rural Health Clinics are eligible to receive program services.⁹ Approximately 41% of all childhood vaccines in the United States are purchased by and administered through the Vaccines for Children Program.¹⁰

Should the Vaccine be Mandatory?

If the vaccine is accessible and affordable to girls and women across the country, it could result in a very substantial decrease in cervical cancer. Requiring the vaccine for school attendance, particularly for pre-adolescents, would be the best way to ensure that most girls are protected, regardless of their economic status. Research has shown that immunizations required for school attendance are the most effective means of ensuring widespread use of vaccines for children and adolescents.¹¹ That is why a policy that requires the HPV vaccine to be mandatory would be much more effective at boosting the vaccination rate than a policy that simply endorses the CDC Advisory Committee's recommendations. However, it is up to each state to decide whether or not to require the HPV vaccine for school enrollment.¹²

Mandatory requirements are controversial, because some people believe that if girls are given the HPV vaccine at a young age, they will be less worried about the risks of sexual activity and therefore be more promiscuous. However, this concern is not supported by the data.^{13, 14, 15}

In clinical trials, Gardasil was tested and found effective in females less than 26 years of age. It is only effective in preventing infection if it is given before infection occurs. That is why it is important to provide the vaccine before sexual activity begins. Research indicates that 13% of U.S. girls are engaging in sexual activity by age 15, which is why Merck and many public health officials are recommending the vaccine's use at age 11 or 12.⁸

If someone has already been infected with one HPV type, the vaccine will not prevent disease from that type.¹⁶ The vaccine's ability to prevent infections and other complications resulting from HPV types 6, 11, 16, and 18 in women without prior exposure to these types is a significant breakthrough, especially since the CDC estimates that 80% of all women in the U.S. will have had a genital HPV infection by age 50.¹⁷

The chances of HPV and cervical cancer increase with the number of sexual partners. As with any sexually transmitted disease, all it takes is exposure to one infected partner to acquire it.

Vaccination Effects and Safety

Minor side effects, such as pain or tenderness at the injection site, were quite common. Other reactions, such as headache, fever, nausea, and dizziness were no more likely after receiving the vaccine than after receiving a placebo.¹⁸ Rare but serious side effects could, however, possibly become obvious after the vaccine is more widely used.

While more research will be necessary to determine exactly how long the vaccine will provide protection against HPV, one thing is clear: since 70% of cervical cancer cases are caused by HPV types 16 and 18, Gardasil has the potential to save women's lives. That is why it is essential to ensure that the vaccine is safe and effective over the long-term, as well as affordable and accessible. Pap smears will still be necessary to diagnose cervical cancer caused by types of HPV that are not prevented by the vaccine.

Merck, the company that makes Gardasil, has been criticized for the high cost of the product. The company has spent millions of dollars on advertising and donations to politicians with the authority to mandate these vaccines at the state level. These criticisms are especially salient because Merck did not fully disclose fatalities in a study of one of their most popular prescription drugs, Vioxx.¹⁹ With Gardasil, as is always the case with new medical products, the safety and risk information available to health professionals and patients is almost entirely dependent on the information reported by the company that makes the product.

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