HPV Vaccine: Protecting Our Girls

By Christina Elston

Is the HPV vaccine a good choice for your daughter?

The new vaccine to protect girls (as young as 9 in some cases) against HPV, the virus that causes cervical cancer, has prompted debate and raised questions about why it's necessary at such a young age.

When the chicken pox vaccine came out in 1995, many parents bristled. Would it work? Was it safe? Some parents went so far as to have "chicken pox parties" so their kids would get the virus and could skip the shot.

Fast-forward to 2007 and there's an even more anxious debate raging over the new vaccine against human papillomavirus (HPV). Gardasil, manufactured by Merck and Co., has raised issues that go beyond the expected concerns about safety and effectiveness. Because it protects against a sexually transmitted virus and is recommended for 11- and 12-year-old girls (but can be given to girls as young as 9), the vaccine has made many parents uncomfortable. Merck's lobbying for states to mandate the vaccine for girls in public schools only added to the anxiety.

With many states still considering legislation requiring girls to be vaccinated, parents find themselves facing a tough decision and lots of questions.

What is HPV?

There are more than 100 strains of HPV, most of which are harmless. About 30 strains, however, can cause cancer and/or genital warts. According to Diane Harper, M.D., an HPV expert at Dartmouth Medical School, 80 percent of women will be infected with at least one HPV strain by age 50. "This is a virus that just about every single woman gets," she says.

Though there is no treatment for HPV infections, 75 percent to 90 percent of cases resolve on their own and do no harm. These cases have no symptoms. But HPV causes cervical cancer in about 11,000 women each year. This year alone, 3,700 of those women will die as a result, according to the American Cancer Society.

The Gardasil vaccine is designed to protect against four strains of HPV. Two of these strains cause about 70 percent of cervical cancer cases, while the other two are linked to 90 percent of genital warts cases.

Could my daughter already have been exposed?

The national Centers for Disease Control and Prevention (CDC) reports that 6.2 percent of girls ages 14 to 19 are infected genitally with at least one of the four strains covered by the vaccine.

Sexual contact is by far the most common way that girls contract genital HPV infection, according to Neal Halsey, M.D., director of the Institute of Vaccine Safety at Johns Hopkins University. "What we worry about in young girls is the cervical exposure, which usually requires [sexual contact]," he says.

Still, there have been cases of HPV infections in girls who've never had sex, according to Harper. This is because HPV can be spread through skin-to-skin contact of any sort, not through the transmission of bodily fluids the way that HIV/AIDS is. "There's no one age at which everybody is going to be HPV-negative," Harper says.

Is the vaccine safe? Does it work?

Gardasil was tested in clinical trials involving nearly 12,000 women, including more than 1,100 girls ages 9 to 15. About 2 million doses of the vaccine were distributed by Dec. 31, 2006, and both Harper and Halsey say there have been no signs that Gardasil is unsafe. The CDC's Vaccine Adverse Events Reporting System (VAERS) has received reports of minor injection-site reactions and other issues, but nothing out of the ordinary.

Harper, who conducted a clinical trial of Gardasil and has been researching HPV for 20 years, says the vaccine performs well, with effectiveness approaching 100 percent.

Does it make sense to vaccinate girls as young as 9, 10 or 11?

Here's where things get tricky. If a girl is already infected with one of the HPV strains that the vaccine is designed to prevent, Gardasil won't protect her against that strain.

With most HPV cases arising from sexual activity - and increasing reports of tweens becoming sexually active - experts are recommending the vaccine starting at age 11 and, if a doctor finds it necessary, as early as age 9. "We never know when our children are going to have their first sexual experience," says Halsey.

On the other hand, the vaccine has so far only been proven to offer protection for about five years, leading some to worry that immunity could wane before young girls even need protection. "If you give the vaccine at age 9, and you have a five-year window, you might not be protecting against much," Harper says.

Is it better to vaccinate early and risk losing immunity too soon, or to delay and hope that your daughter isn't infected with HPV before she is immunized?

"It really becomes a personal matter," Harper says.

She also advises parents to watch for upcoming reports regarding HPV boosters, which will be recommended if experts determine that immunity from the vaccine diminishes over time.

When it comes to older adolescents, Harper believes a close relationship and open communication between parent and daughter are the best tools in deciding when to vaccinate.

What if my daughter is already infected?

Girls who already have HPV infections can still benefit from the vaccine. Gardasil would protect them from any of the four strains they are not currently infected with.

Testing for HPV requires a vaginal swab (or Pap test), and isn't appropriate for women under age 21 unless they've been sexually active for three years, Harper says. If, however, your daughter has tested positive for one or more of the preventable HPV strains, you can either wait for the infection to clear before vaccinating for full protection, or vaccinate right away and get immediate protection from the other strains. Infections usually resolve within six months to a year.

Remember, though, because the vaccine only protects against four strains of HPV, all women are still at risk for cervical cancer. Regular pelvic exams with Pap tests are a must. "The Pap," says Harper, "is still your best safety net."

For more information about HPV and the HPV vaccine, visit the CDC online at www.cdc.gov/std/hpv/.

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