Q&A: Cervical Cancer Vaccine

Q: Is the Gardasil vaccine safe?

A: Gardasil, a vaccine to prevent cervical cancer, has been widely used in the United States since its approval by the Food and Drug Administration in June 2006. The vaccine works by targeting the cancer-causing strains of the human papillomavirus, or HPV, that cause the majority of cervical cancers.

As with any new medicine or vaccine released for public use, there are always concerns about whether it will be safe when used as directed in the general population. An article published in the Journal of the American Medical Association in August reviewed the side effects that have been reported to a central database since the vaccine’s release.

The good news is that there were no real surprises in terms of side effects from Gardasil. The reactions were what would be expected from the information collected during the clinical trials that led to the vaccine’s approval.

More than 23 million doses of Gardasil were distributed in the U.S. from June 2006 through December 2008 (Gardasil is a three-dose vaccine). Of the more than 12,000 reported adverse events, fainting was the most common, and occurred 8.2 times for every 100,000 doses of the vaccine given to patients. Fainting is not uncommon after vaccination, according to the report, especially in young women ages 11 to 18. Realizing that someone could faint should alert parents and medical professionals to take precautions, such as keeping the patient in the doctor’s office for 15 minutes after the vaccine is given.

Other commonly reported side effects included reactions at the site of vaccination, dizziness, nausea, headache, hypersensitivity reactions, and urticaria (hives). About 6 percent were considered serious, including blood clots, autoimmune disorders, a form of paralysis called Guillain-Barré syndrome, and 32 deaths. Unfortunately, the researchers were not able to look at all the medical information of these patients, so we don’t know for certain whether the reactions were related to the vaccine or just coincidental.

It is always important to weigh the risks and benefits of any vaccine. For now, it appears Gardasil is reasonably safe and effective, but further monitoring of side effects is ongoing.

The American Cancer Society continues to recommend Gardasil for girls ages 11 and 12, and as young as 9 years old. Girls between 13 and 18 also should be vaccinated. Although the vaccine is approved for women ages 19 through 26, the Society does not believe there is sufficient evidence to show benefit in this age group because of the risk of previous HPV exposure. These women should talk with their health care professionals to determine whether or not they would benefit from vaccination.

The ACS is currently reviewing data on the HPV vaccine Cervarix, which the FDA approved in October (see “Second HPV Vaccine Approved, Plus Gardasil for Boys”).

—Len Lichtenfeld, MD, is deputy chief medical officer for the American Cancer Society