Turns Out, You Could Still Be at Risk for HPV Even if You Had the Vaccine

A convincing argument to continue using condoms—even if you've gotten the shots

If you had the HPV vaccine when you were younger, that means you don’t ever have to worry about getting the disease…right?

Wrong. A recent study presented at the annual meeting of the American Association for Cancer Research found that women who’ve had Gardasil (the original HPV vaccine) could still be at risk for certain high-risk strains of the disease. (The study hasn't been published in a journal yet.)

HPV is the most common sexually transmitted disease, and it can lead to cervical cancer. While there are about 200 types, only about 40 strains are spread through sex, and only a handful are associated with cervical cancer. Gardasil is available for young women ages 9 to 26 and boys ages 9 to 15.

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For the study, researchers from the University of Texas Medical Branch at Galveston (UTMB) analyzed data from 592 women ages 20 to 26. Eighty of them had gotten Gardasil, while the rest of the women were not vaccinated against HPV. Those that had Gardasil were less likely to be infected with one of the four strains (6, 11, 16, or 18) that the vaccine protects against: 11 percent of the women who had Gardasil were infected with one of the four strains, compared to 20 percent of the unvaccinated ladies.

The vaccinated women who were found to be infected were most likely exposed to the HPV virus before getting Gardasil, says Abbey Berenson, M.D., Ph.D., a professor in the department of obstetrics and gynecology and pediatrics at UTMB. "The vaccine does not protect against infections that existed before a patient was vaccinated," she says.

Here’s the scary part, though: 60 percent of the women who had Gardasil were actually infected with other high-risk strains of the disease that the original vaccine doesn’t protect against, compared to 40 percent of the unvaccinated women. Whoa.

The researchers factored in things that could raise the risk of HPV (such as how many sexual partners the women had), yet they found that the women who had the Gardasil shot were still 40 percent more likely to contract one of the high-risk strains not covered by the vaccine. Berenson explains that this was likely a chance finding. "The measures in this study were only taken at one point in time, and the sample was relatively small," says Berenson.

Alyssa Dweck, M.D., an ob-gyn and the co-author of V is for Vagina, who was not involved in the study, says it's possible that women who've been vaccinated may feel more protected and therefore might exercise less caution when it comes to practicing safe sex—which could help explain why the ladies in the study who got their shots were more likely to become infected with these other strains of HPV.

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So what does that mean for you? The researchers suggest that women who’ve had the Gardasil shot could benefit from getting a new version of the vaccine—Gardasil 9—that protects against nine strains of HPV, which was approved in December 2014. However, this shot, like the original vaccine, is only recommended for women ages 9 to 26 (since most women over 26 have already been exposed to the virus, which would reduce the vaccine's efficacy). It's also important to keep in mind that the study only looked at a small group of women. "When you think about the millions of people getting this vaccine, [80 women] is a pretty small group," says Dweck.

That being said, practicing safe sex is crucial—whether or not you've been vaccinated. Condoms don't fully protect against HPV (it's spread through skin-to-skin contact so they don't offer enough coverage), but they can still lessen the chance of getting it. HPV can also be spread through anal sex and most likely through oral sex, as well, so condoms and dental dams are still super important to use, says Dweck. And when it comes to cervical cancer, check in with your ob-gyn about how often you should be getting tested. Dweck points out that the guidelines have recently changed. Starting at age 21, you should get a pap smear every three years until age 30. Once you hit 30, you can either get a pap smear with an HPV test every five years or a pap smear without the HPV test every three years.