According to a new study, human papilloma virus (HPV) rates have plummeted in the first six years vaccines against the virus have been available. Unfortunately, HPV vaccination rates lag behind those of other recommended inoculations, in part because of the stigma that stifles conversations around sexually transmitted infections.
Perhaps these new success rates—coupled with additional new research that reminds us of the possibility of non-sexual HPV transmission—will convince more parents to take advantage of this potentially life-saving vaccine.
HPV is actually a group of more than 150 related viruses, 40 of which are known to be sexually transmitted. Most types of the virus are thought of as low-risk, because they are unlikely to cause health problems. Nine types, however, have been identified as high-risk and are thought to be responsible for 99 percent of cervical cancers and a large portion of vulvar, vaginal, penile, anal, and oropharyngeal (a part of the throat) cancers.
Since 2006, there have been three vaccines against HPV developed and released on the market. The most recent, made available last year, was the most wide-ranging; it protects against the nine high-risk types of the virus.
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The vaccine is given as a series of three shots over eight months. The Centers for Disease Control and Prevention (CDC) recommends that boys and girls begin the series at age 11 or 12 in order to be sure that they are fully vaccinated before they become sexually active, but those who do not get the shots at that time can get them at any point before age 26. Experts estimate that widespread vaccination could prevent up to 90 percent of cases of cervical, anal, and genital cancer.
Though the research released last month uses data collected before the latest vaccine was available, the success of the original vaccine supports an optimistic outlook for the future prevention of HPV.
For the new study, which was published in the journal Pediatrics, researchers used data from the CDC’s National Health and Nutrition Examinations Survey (NHANES). They compared cervical and vaginal specimens from individuals ages 14-to-34 collected between 2003 and 2006—before the vaccine was available—with samples collected between 2009 and 2012, after the first vaccine was in use. They also used vaccination records from the latter group.
They found that 11.5 percent of young women ages 14-to-19 in the pre-vaccine group had one of the four types of HPV covered by the original vaccine. This dropped to about 4 percent in the group examined after the vaccine was available. Among those ages 20-to-24, the prevalence rate dropped from 18.5 percent to roughly 12 percent. There was no change among the oldest age group.
Overall, the study concludes, within six years of the vaccine’s introduction, HPV rates were down 64 percent among teen girls and 34 percent among women in their 20s.
Dr. Laurie E. Markowitz, lead author of the study, told the Guardian that results were better than expected.“The fact that we are seeing a larger decrease overall than what we expect given our coverage rates does suggest there may be some herd protection,” which occurs when a large enough portion of the population is vaccinated to slow the spread of the virus, she said. “There also may be effectiveness from less than a complete three dose series,” Markowitz continued.
Researchers anticipate that more people will continue to benefit from the vaccines. Markowitz told the Guardian, “As women who got the vaccine when they were younger age move into these older age groups, we should continue to see a continued decrease,” because they will not transmit the strains to anyone else as they become sexually active.
In addition, vaccination rates have improved since this data was collected. In 2009, only about 44 percent of girls had received one dose of the vaccine and only about 27 percent had received all three. By 2014, two-thirds of teenage girls ages 17 and under had received at least one of the three recommended doses of the HPV vaccine, and about 40 percent had received all three doses.
The CDC recommends that boys get the HPV vaccine as well, but vaccinations rates among boys have always been lower than those among young women—perhaps because when the vaccine was originally introduced, it was only suggested for girls, or perhaps because it is best known for preventing cervical cancer. But vaccination rates for boys have been on the rise as well. In 2014, roughly 42 percent of teenage boys ages 17 and under had received at least one dose of the vaccine: about 8 percentage points higher than the year prior.
Unfortunately, HPV vaccination rates still lag behind those of other recommended vaccines. For comparison, in 2014, about eight in ten teens ages 17 and under had received the quadrivalent meningococcal conjugate vaccines and roughly 87 percent had received the Tdap vaccine, which covers tetanus, diphtheria, and pertussis.
There are a number of reasons that HPV vaccination rates might be lower than others, including the fact that only two states and Washington, D.C. require the vaccine for school-aged children. By contrast, the Tdap vaccine is required in most states; meningitis vaccines are required in about half. Additionally, some parents may not have the resources or time to take their children to get a series of three vaccinations.
Not surprisingly, there still exists a discomfort with the sexually transmitted nature of HPV. Since, the HPV vaccine was introduced, there have been those who argue that vaccination will be seen by teenage recipients as permission to have sex, thereby increasing their risky behavior. This faction also argues that it is not necessary to inoculate young people against HPV because they can easily avoid it by just not having sex.
Numerous studies have found that HPV vaccines do not, in fact, turn young people into sex machines. A study last year from the United Kingdom, for example, found girls who have been vaccinated are less likely to engage in risky sexual behavior than those who have not. An earlier study in the United States found that teen girls who had been vaccinated were more likely to use condoms than their non-vaccinated peers. Other studies have found that young people’s perception of sexual risk and risk behaviors do not change after vaccination.
Perhaps a new article will take the wind out of the sails of the argument that teens should “just say no” to prevent HPV. The paper, cleverly titled “Penises Not Required,” reviewed 51 studies that found evidence of transmission through means other than penile-vaginal or penile-anal intercourse. Some of the studies reviewed found HPV DNA in the genital tract of female “virgins”—though the definitions of “virgin” varied widely among studies, and were based on respondents’ self-reported sexual activity. Other studies found HPV DNA in children who had not been sexually abused. Some studies focused on evidence of HPV DNA on medical equipment, toilet seats, and sex toys, and questioned whether this would be sufficient to transmit the virus. And others suggested the possibility of finger-to-genital transmission either from a partner or even from one’s own hands.
The researchers told Rewire in an email that their results have to be interpreted cautiously, as they do not provide proof of non-penetrative or non-sexual transmission. Nonetheless, the possibility that this virus can be transmitted without sex should help us rid the HPV vaccine debate of moralizing. As the researcher concludes in the article, “The distribution of HPV vaccines has been hindered, in part, by societal discomfort with the role of HPV in human sexuality. A fuller appreciation of the potential for non-sexual HPV transmission could help increase vaccine acceptance.”
The facts are simple. We have a vaccine that prevents cancer, it’s working, and that’s a major public health victory. It’s time to stop arguing about whether vaccinating kids against an STD is a good idea and start protecting everyone.