Gardasil, the Human papillomavirus (HPV) vaccine that protects against cervical cancer, has been out 14 years. How is it working? Do we really need a vaccine for HPV? If so, who should get it—and when? One of America’s top experts on HPV and the vaccine addresses these and other concerns…

I’ve heard that just about everyone gets HPV…and that the virus clears up on its own if you do get it. So why do we need a vaccine?

HPV does infect most people at some point in their lives. It is primarily spread by sexual contact, although it can also spread other ways, such as a pregnant woman can transmit it to her unborn child. Since the virus usually doesn’t cause symptoms, most people don’t even know they have it. And 90% of HPV infections clear up within two years.

Having had and cleared HPV from your body does impart antibodies to the virus, which could last a very long time. But while tests can show that you do or don’t have HPV virus in your body, there is no test that shows if you have antibodies to the virus. So there’s no way of knowing if you’re part of the 10% infected with the virus who did not clear it. And HPV can stay dormant for up to 20 years or more…until a period of weakened immunity causes it to become active and cause disease.

Gardasil (human papillomavirus 9-valet vaccine, recombinant, the full name of the vaccine) protects against the nine strains of HPV that cause the majority of HPV-related cancers, including the two most virulent—HPV-16 and HPV-18. Even if you have natural antibodies to HPV, that is not as protective as what the vaccine provides.

If HPV is sexually transmitted, why should my son/daughter be vaccinated now—many years before he/she is likely to be sexually active?

Gardasil was approved for boys and girls, men and women, ages nine to 45. However, the age at which to get the most benefit from the vaccine is age 11 or 12.

Parental qualms are understandable. However, research shows that these years are best because it is a time when there has been the least exposure to HPV (precisely because children this age are unlikely to be sexually active)…while at the same time it is the age when immune systems are fully developed, allowing the maximum number of antibodies to be produced from the vaccine. And from a practical standpoint, other immunizations are being given at that age, so it’s easy to remember to get it done.

Men (obviously) don’t get cervical cancer. Why do they need to be vaccinated for HPV?

While most people hear about HPV and cervical cancer, the virus is tied to at least six different types of cancers and several noncancerous conditions, many of which affect men, too—such as respiratory tumors and genital warts. Oral cancer, which affects men three to five times more than women and at younger ages, is especially a concern. In fact, rates for oral cancer now surpass cervical cancer in the US.

Men are especially vulnerable because they do not get HPV screening tests such as the pap and HPV DNA tests that women get. And there is no screening test for HPV-related oral cancers. Plus, infected men can pass HPV to their partners.

Are there any side effects from the vaccine?

So far, Gardasil has been shown to be very safe—no adverse effects have been reported. The most common adverse reactions have been mild and temporary, similar to those for other vaccines, such as pain and swelling at the site of the injection, and usually go away within 24 to 48 hours.

A few episodes of fainting were reported when the vaccine first came out. However, fainting among preteens from any kind of injection is more common than at other ages. However, in an abundance of caution, doctors now have patients sit for 15 minutes after the injection.

Another concern has been Gardasil poses a risk for Guillain-Barré syndrome. This immune system disorder affects about one to two people out of 100,000 in the general population, vaccinated or not. No data so far find that the rate among those vaccinated with Gardasil is any higher.

How long does the vaccine last? If you get it at age 13, will you still be protected at age 50 or 60…or beyond?

Gardasil has been found to be 98% effective at preventing cervical cancer over the 14 years since its approval in 2006. Studies from around the world confirm that it prevents about 90% of HPV infections.

Because of the unique way the vaccine is formulated, levels of antibodies in the body are expected to remain high for a long time—possibly for 30 years or more. And in fact, studies that measured HPV antibodies in people who were vaccinated even 10 years ago are finding that antibody levels have not fallen.

That said, we don’t know yet whether a booster will be needed down the road. We’re also working on developing a single-dose vaccine (right now, it is a multishot deal—two doses if started before age 15, three doses if started after age 15 or if you have a weakened immune system).

Can girls and women who got the vaccine skip getting pap tests?

Definitely not! Good as the vaccine is, it is not 100% protective against HPV. For nearly 100% protection, women need the pap test, HPV DNA test and the vaccine.

Eventually, if the vaccine becomes something all people get, it could reduce the HPV viral pool—and potentially also eliminate many of the diseases and cancers caused by HPV.

Want to learn more? Click here to listen to Bottom Line president Sarah Hiner’s interview with Dr. Krishnan, “The HPV Vaccine Debate Rages On.”