Consumer Reports Insights

Gardasil protects against cervical cancer, but the vaccine's risks are a concern

(Harry Cabluck/associated Press)
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Tuesday, March 9, 2010

Should you expose your young daughter to potential risks from a vaccine that protects against cervical cancer, a disease that she may get 20 to 40 years from now?

That's a question millions of parents face as television ads push for girls to receive Gardasil, a vaccine that prevents infection from four types of human papillomavirus (HPV), the most common sexually transmitted virus in the United States. Those four types cause most cases of cervical cancer and genital warts.

The Food and Drug Administration approved Gardasil in 2006 for girls and young women to prevent cervical cancer and genital warts caused by some types of HPV. But complaints have emerged about the marketing and cost of Gardasil, and some parents have raised concerns about its safety. A new report (at by the FDA and the Centers for Disease Control and Prevention found that serious complications had occurred, although the rate and severity of most side effects appear to be consistent with those of other vaccines.

To help you weigh the risks and benefits of Gardasil, Consumer Reports reviewed the evidence.

How effective is Gardasil?

Studies involving about 21,000 girls and women found that for those who were not infected with HPV at the time of vaccination, Gardasil was highly effective in preventing precancerous cell changes that often develop into cancer of the cervix, vagina and vulva, and in preventing genital warts.

But if a girl or woman is already infected with one of the HPV types in the vaccine, Gardasil will not treat the infection nor prevent disease from that type. Moreover, because the vaccine doesn't protect against all HPV infections, it won't prevent about 30 percent of cervical cancers and 10 percent of genital warts. That's why Pap smears are still essential for early detection of cervical cancer, which has no symptoms until it's advanced. Protection from the vaccine is expected to be long-lasting, but the duration of immunity is not yet known.

Who should get the vaccine, and when?

Gardasil provides maximum benefit when it is administered before a girl or woman becomes sexually active. It's recommended for 11- and 12-year-old girls, but it can be given to those as young as 9 and to women up to age 26. Young women who are already infected may still partially benefit from the vaccine because very few have been infected with all the HPV types that it targets.

What are the risks?

Reports of side effects and complications following vaccination are collected by the Vaccine Adverse Event Reporting System (VAERS), which is managed by the FDA and the CDC. The reports are unconfirmed and not necessarily related to the vaccine. In a 2009 review of the data, the agencies reported that more than 23 million doses of Gardasil were distributed between 2006 and 2008, and 12,424 reports had been filed. Most of those were not serious and involved pain and redness at the injection site, dizziness, nausea, headaches and fainting.

But 6 percent of the reports were serious. They included blood clots and Guillain-Barré syndrome, a disorder that causes muscle weakness and tingling that can progress to paralysis. There were also 32 reported deaths, but they had no common pattern that would suggest they were caused by the vaccine. In most of the cases that had medical documentation, the deaths were linked to other factors, such as diabetes, viral illness, illicit drug use and heart failure.

What safety precautions can you take with Gardasil?

People with minor illnesses (for example, diarrhea or a mild upper respiratory tract infection) can get the vaccine, but those with moderate or severe illnesses should wait until they recover. To prevent falls in case of fainting, the vaccine recipient should remain seated or lying down for 15 minutes after the injection while a health professional observes her.

Seek medical attention if you notice any unusual conditions after the vaccination, such as a high fever or behavior changes.

Signs of a serious allergic reaction include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heartbeat or dizziness.

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