Since the Food and Drug Administration (FDA) approved the HPV vaccine, Gardasil, last summer, doctors have disagreed over who should get the vaccine. The government approved it for girls and women ages 9 to 26, and public health experts say the youngest girls those who haven't had sex yet need it most. But some clinicians say there's no reason women older than 26 wouldn't benefit from it too.
The argument against a wider application of the vaccine is that it's a preventive measure, not a therapeutic one. (An Aug. 15 study in the Journal of the American Medical Association found that Gardasil did not cure women who had already developed cervical cancer or had existing HPV infections.) Though vaccinating girls early can drastically stem the spread of the virus, by the time they get older and start having sex, the vaccine may provide little protection.
From a public health standpoint, that logic seems to makes sense. Since at least 80% of women who have sex will acquire the virus by age 50 (in most cases it causes no health problems and clears the body within two years), it accomplishes little to give the vaccine to older, sexually active women, who may already have HPV or have already spread it within the community. But humanpapillomavirus isn't a single virus; rather, it's a family of viruses that includes at least 100 strains, more than 30 of which are transmitted sexually. About 10 of those can cause cervical cancer; others may cause genital warts. So even if a woman has been exposed to one strain of HPV, there may well be others that she is still vulnerable to. HPV also poses a threat to men because some strains likely spread through oral sex can lead to cancers of the mouth and throat. A new analysis of U.S. head and neck cancer trends published in the Oct. 1 issue of Cancer suggests that young men be vaccinated too.
Gardasil, which is the only currently available HPV vaccine, protects against only two of the types of HPV that cause cancer: the strains numbered 16 and 18. Yet these two strains account for 70% of all cervical cancer cases. Cervarix, an HPV vaccine developed by GlaxoSmithKline, which expects federal approval for the drug in 2008, is designed to protect against four strains of HPV 16, 18, 31 and 45 that together account for 80% of all cervical cancers worldwide. Overall, only a small percentage of women who have had persistent infections with even the high-risk HPV strains are at risk for cancer.
Still, say some doctors, it makes absolute sense to give the vaccine to older women, regardless of previous exposure. As yet, there's no easy test to diagnose which particular strain of HPV a woman has or has had. "We don't have any way of telling at this point whether a sexually active woman has been exposed or not to a strain of HPV that can cause cancer," says Dr. Alan Waxman, professor of obstetrics and gynecology at the University of Mexico School of Medicine. Waxman is one of several HPV experts who advise women to consider getting the vaccine, even if they've acquired the virus in the past.
"You don't know whether you've been exposed to all the [strains protected by] the vaccine," says Dr. Richard Schlegel, a professor at Georgetown University Medical School who is developing a second-generation HPV vaccine. "Clearly if you haven't been exposed, it would be worthwhile to get it."
For many women, perhaps the biggest hurdle to getting the three-shot vaccine is its $400 price tag. Women over age 26 have to pay for it out of pocket: currently, insurance companies don't cover older women because the FDA hasn't specifically approved the vaccine for them. Also, many practicing gynecologists don't know that the vaccine works against several strains of HPV, according to Dr. Diane Harper, director of the Gynecological Cancer Prevention Research Group at Dartmouth Medical School. If a patient has already been exposed to HPV, the gynecologist may advise her that the drug is not worth the money.
Women should be aware, however, that the vaccine doesn't offer blanket protection against cervical cancer, says Harper, and all women should still get regular pap smears.
Gardasil's maker, Merck, hopes the FDA will extend approval for the vaccine's use in older women in 2008. The company is currently conducting research on women ages 26 to 45 to study the vaccine's efficacy and side effects. Though older women can get the vaccine "off-label," for now there's no hard data on whether it's as effective in that group as in younger women.
That doesn't stop Tamika Felder, founder of the Washington, D.C.based Tamika and Friends, Inc., which educates women about HPV and encourages them to get the vaccine. Felder, 31, a survivor of cervical cancer, holds popular "HPV parties," where women learn about the virus through frank discussions and sometimes risque versions of party games. Since 2005, Felder has helped organize more than 300 HPV parties nationwide. "Older women want to know about HPV and they feel left out," she says. But once educated, Felder says, many women decide to get the vaccine. "I talk to a lot of women and they say they want it," Felder says. "They're saving up for it and giving up a pair of pumps to pay for it."
An earlier version of this story failed to state that the HPV vaccine Gardasil protects against two strains of HPV that cause genital warts, strains 6 and 11, in addition to the two cancer-causing strains, 16 and 18. The earlier version of the story also incorrectly stated that the HPV vaccine Cervarix is designed to protect against four types of HPV that cause cervical cancer. In fact, it is specifically designed to provide complete protection against types 16 and 18. Clinical data suggest, however, that it also protects against two additional cancer-related strains, types 31 and 45.