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Canadian Living: How does the new vaccine differ from previous HPV vaccines?
Dr. Vivien Brown: The original two vaccines—one of which protected against two subtypes of HPV and the other of which protected against four—covered HPV subtypes 16 and 18, which are the most aggressive and most common cancer-causing subtypes; those account for about 70 to 75 percent of the cancers caused by HPV. There are other less common subtypes that weren’t in the original two vaccines. We’ve been able to add five more of those subtypes to cover more cancer so that the actual effectiveness of the vaccine is greater. The new vaccine adds another 20 to 25 percent of HPV-related cancers, so the HPV protection that was 70 to 75 percent is now 90 to 95 percent.
CL: What kinds of cancers does the new vaccine protect against?
VB: It has been tested against cervical cancer primarily, but also vulva cancer, vaginal cancer and anal cancers. While it hasn’t been formally tested against throat cancers, throat cancers are HPV-related, so we’re watching to see if there’s a reduction in those cancers in people who have been immunized.
CL: Who should get this vaccine?
VB: The first group recommended to be immunized is boys and girls between the ages of nine and 26. The earlier you start, the better your immune system. We’re getting to them before they’ve been exposed. The primary focus is still on young people who have not been exposed, but it is approved in Canada for people who are older. So when I have someone in my practice who is 28, instead of 26, of course I’m going to offer immunization. But if I have someone who is 40 and has been in a monogamous relationship for 20 years, I don’t think I need to offer her the vaccine, unless she feels a need for it.
CL: What about people who received an earlier version of the HPV vaccine?
VB: We don’t have an answer for that yet. It wouldn’t hurt to take the additional vaccine, but we don’t know if they’re going to need one shot, two shots or three shots. We’re watching the [U.S.] Food and Drug Administration, and the Advisory Committee on Immunization Practices [ACIP]—which advises the Centers for Disease Control and Protection—for their best recommendations. For 10- or 12-year-olds, I would recommend Gardasil 9 so they’re getting the most widespread protection. What ACIP has said so far is that if you started with Gardasil 4, you can finish with Gardasil 9 [because immunization involves three shots over the course of six months]. But if you were immunized two or three years ago, you can discuss it with your physician; whether you might want another shot depends on your risk and what you’re being exposed to.
CL: What do you want people to know about the vaccine?
VB: One of the most exciting things is we have a vaccine that’s actually preventing cancer. I don’t know if the public understands how exciting that is. If I said I had a vaccine that could prevent breast cancer by 90 to 95 percent, they’d be lined up around the block. In my lifetime as a physician, I’ve had a 28-year-old die of cervical cancer, but I’m not going to see that again.
Talk to your doctor about the HPV vaccine and make sure you know what protection you’re getting from it; there’s now a range of options with different levels of protection on the market. And remember: No vaccine is 100 percent effective. Learn about preventing cancer with regular screening, too.