Are You a Candidate for a Cervical Cancer Vaccine?

On June 8, 2006, the U.S. Food and Drug Administration approved Gardasil, a vaccine that protects against the human papillomavirus or HPV. HPV is infamously known as the cause of genital warts and—more importantly—the root of most cervical cancers.

Globally, cervical cancer is the second most common cancer in women, and in the U.S., nearly 4,000 women will die from the disease this year, according to the National Cancer Institute. Consequently, doctors and public-health experts are touting the new vaccine as a landmark drug in women’s health.

The vaccine is targeted to females 9 to 26 years old—the only age range tested in the drug’s preliminary research trials. The hitch is this: Cervical cancer typically occurs in midlife, with nearly half of the women diagnosed with the disease being between the ages of 35 and 55, according to the CDC.

The hailed advent of Gardasil, produced by pharmaceutical giant Merck, has left many women wondering whether this drug is only for the innocent young, or if it could also safeguard mature and sexually active women who are at a higher risk for cervical cancer. 

Experts weigh in on who may and may not benefit from the vaccine.

Partial Immunity Better Than None

HPV is a group of viruses that includes more than 100 different strains. “You can get infected with one of these strains on your first sexual encounter, and it is not easy for your doctor to tell if you are infected,” says Dr. Harry Hull, the state epidemiologist from the Minnesota Department of Health. Dr. Hull is also one of 15 experts on the CDC’s immunization advisory committee, which will endorse federal recommendations for Gardasil later this month. These recommendations mandate how and when the vaccine should be administered, who should get it and if it is a mandatory or voluntary immunization.

If a woman is infected with an HPV strain before receiving the vaccine, future immunity against that strain is impossible. As a consequence, sexually active women and women already infected with HPV strains are not ideal candidates for the vaccine, says Dr. Hull.

But women within these categories shouldn’t discount the drug just yet. Among the many HPV strains, only four cause nearly all of the world’s cervical cancers and genital warts: Types 16 and 18, and Types 6 and 11, respectively. Gardasil is designed to target these. “So even if you've been infected with one of these strains, you are still going to benefit from vaccination against the other three strains,” says Dr. Hull.

So sexually active women may not achieve total immunity, but partial immunity is certainly better than none.

Off-Label Prescription

Gardasil is licensed only for females ages 9 to 26, and it will take years for Merck to test the vaccine’s efficacy on a broader age range. Until then, doctors may choose to prescribe Gardasil for women beyond the age of 26, but only if the conditions are right. “This means that the patient has had normal Pap smears all of her life and there is no evidence that she is infected with an HPV strain,” says Dr. Bradley Busacco, a gynecologist and obstetrician in Cincinnati, Ohio.

Not all physicians will feel comfortable prescribing the vaccine off-label. (Off-label means that the drug will be used in a way that is not specifically endorsed by its manufacturer—in this case, prescribing it for women exceeding Merck’s age recommendations.) Women beyond the age of 26 who wish to be vaccinated must discuss their medical history and the issue of off-label prescribing with their gynecologist.

Women in older age demographics may soon have another option for cervical cancer protection. By the year’s end, the FDA is expected to review and approve a second HPV vaccine, Cervarix (produced by GlaxoSmithKline). Initial studies indicate that Cervarix is safe and effective against HPV infection in women age 15 to 55 years. Unlike Gardasil, GlaxoSmithKline’s drug is not designed to immunize against genital warts, but it will protect women against the two leading cancer-causing HPV strains: Types 16 and 18. Previous infection of one of these HPV strains will compromise Cervarix’s immunity, and previous infection of both of these HPV strains will negate the vaccine’s immunity