The Pap test has greatly reduced the incidence of cervical cancer, but 275,000 women worldwide still die from it each year, including more than 4,000 Americans. That’s why the approval of the HPV (human papillomavirus) vaccine in 2006 was such a breakthrough. The vaccine acts against two strains of HPV that cause about 75 percent of cases of cervical cancer.
During my 25 years in practice I occasionally saw women who developed invasive cervical cancer, usually because they hadn’t had Pap tests, which can find precancerous lesions and early cancers so they can be treated and cured. It’s a terrible disease, and the development of the vaccine made me hope that this cancer would become exceedingly rare.
If that wasn’t enough, the vaccine additionally protects against oral (head and neck) and anal cancers, which are often caused by these two HPV strains and occur mostly in men. Michael Douglas recently brought attention to the link between oral cancer and HPV when he suggested that his throat cancer was caused by this infection, presumably acquired during oral sex. What’s more, the first HPV vaccine, Gardasil, also targets two other HPV strains that cause 90 percent of genital warts. A second vaccine, Cervarix, acts only against the two cancer-related strains.
These four strains of HPV are sexually transmitted, so the vaccine (a series of three shots) should ideally be given to all children before puberty; the Centers for Disease Control (CDC) recommends age 11 or 12. But all unvaccinated people through age 26 should get the shots. I recommend Gardasil because of its broader coverage. If someone becomes infected before being vaccinated, the vaccine won’t be effective against that particular strain, but will still protect against cancer and genital warts caused by the other strains covered by the vaccine.
A recent Australian study in the journal BMJ showed how effective Gardasil can be against genital warts. During the first five years of a national HPV vaccine program, the incidence of the warts in women under 21 declined by 93 percent. Even though boys and men were not vaccinated back then (they are now), the reductions in genital warts among heterosexual males were nearly as impressive, thanks to HPV suppression in women (this phenomenon is called herd immunity).
“These are exciting times in the science of HPV,” according to the editorial accompanying the Australian study, “and the world can confidently look forward to the virtual elimination of genital warts, most genital cancers and some 60 percent of head and neck cancers.”
Sadly, these outcomes are far from assured in the U.S. because HPV vaccination rates have been dropping, not rising. While in Australia (and some other countries) about 80 percent of 12-year-old girls were vaccinated in 2010, the rate in the U.S. is less than half that. It’s an American tragedy, the result of parochialism, prudery and politics.
A big factor is American parents’ reluctance to have their daughters vaccinated. A study published in Pediatrics in March found that nationwide, 44 percent of parents said they would not have their teenage daughters vaccinated, a rate that has been inching up. The reasons? Many said the vaccine is unnecessary (definitely not true) or dangerous (ditto). Some said they would opt out because their daughters were not sexually active (exactly when the vaccine is most effective) or hesitated over fears that the vaccine might give teenagers license to have sex (many studies have found that it doesn’t alter sexual behavior).