![\"Preteen](\"http:\/\/oralcancernews.org\/wp\/wp-content\/uploads\/2013\/04\/vaccine01.jpeg\")
<\/a>Preteen and adolescent girls and boys are priority groups for vaccines that prevent human papillomavirus infection.
\u00a9 Jessica Rinaldi\/Reuters\/Corbis<\/p><\/div>\n
Back in 2006 and 2009, when the HPV vaccines Gardasil and Cervarix came onto the market, health officials dreamed of halting the spread of HPV, which is sexually transmitted, in a single generation. Scientists call such blanket coverage herd immunity \u2014 in which a pathogen gets vaccinated into oblivion, becoming so rare that even unvaccinated people are protected.<\/p>\n
With such heady potential, Gardasil, developed by Merck, and Cervarix, created by GlaxoSmithKline, should be an easy sell. They rev up a potent immunity against HPV 16 and 18, the two types of the virus that account for most cases of cervical cancer. Gardasil also prevents most genital warts. The immunity the vaccines provide is many-fold better than the weak protection engendered by a run-in with the virus itself, and since approval, both vaccines have proven safe. A study of nearly 190,000 girls and women, published in 2012 in Archives of Pediatric and Adolescent Medicine<\/em>, found that the shots\u2019 most common side effects were mild skin infections and fainting.<\/p>\n But the hope for herd immunity against HPV anytime soon is fading fast in most of the West. By 2011, only 53 percent of U.S. teenage girls from 13 to 17, a target group for the vaccines, had received them.<\/p>\n \u201cIt\u2019s a disaster,\u201d says Andreas Kaufmann of Charit\u00e9 University Medicine Berlin, who sees the problem from the perspective of a biologist. \u201cHPV is strictly species-specific. It only occurs in humans.\u201d<\/p>\n WHY WAIT? That means with mass vaccination, the virus would have no safe harbor in nature. \u201cTheoretically, we could eradicate these HPV types, like we did smallpox,\u201d he says. \u201cWe could end it.\u201d<\/p>\n What\u2019s the problem? For one thing, parents are uneasy about vaccinating a preteen against a virus associated with sexual activity. Researchers have found that some parents believe vaccination might lead to greater promiscuity. And a public scare about vaccines in general \u2014 including a false report linking the measles vaccine to autism \u2014 has contributed to the confusion. Not only that, but the vaccine is delivered in a three-shot regimen. Even among girls who get vaccinated, completing the course isn\u2019t a certainty. Many U.S. preteen and teenage girls who start the course fail to get all three shots, and thus are less apt to be protected.<\/p>\n In the United States, responsibility for tracking kids\u2019 HPV shots often falls to pediatricians, since the vaccine isn\u2019t administered in schools. But pediatricians are notoriously overworked and \u2014 relative to many other physicians \u2014 underpaid. Doctors often need to cover vaccine costs up front to have them ready for patients, says Kevin Ault, a gynecologist at Emory University in Atlanta. Pediatricians also have to remind a patient to return for subsequent shots and often find themselves on the front line in contending with doubtful parents, says Noel Brewer, a health psychologist at the University of North Carolina in Chapel Hill. Instead of mass vaccinations in schools, the HPV vaccines depend on this hit-or-miss distribution system managed by individual doctors who, even if they advocate vaccination, may not want to cross parents. The result is often family indecision, procrastination and outright rejection.<\/p>\n <\/p>\n FALLING BEHIND Then there\u2019s the behavior of the virus itself. The vaccines don\u2019t work in people who have active HPV infections, and it\u2019s difficult to know who those people are. The cancer-causing HPV types are stealthy, giving rise to phantom infections with no symptoms and an iffy risk of cancer far off in the future. These characteristics make the risks posed by HPV hard to grasp, says Christina Dorell, a physician at the Centers for Disease Control and Prevention. \u201cWith polio, people were getting sick and going to the hospital,\u201d she says. \u201cWhen the image of illness is removed from a group, you may have a little less sense of urgency coming from parents.\u201d<\/p>\n Girls might see it differently, studies show. Doctors\u2019 opinions matter to them. Those who receive a recommendation from a doctor are 2.6 times more likely to get vaccinated than girls getting no counsel, researchers reported in Pediatrics in 2011. Also, \u201cthere is no evidence of increased sexual-risk behavior, such as decreased condom use or earlier intercourse,\u201d says Gregory Zimet, a clinical psychologist at the Indiana University School of Medicine in Indianapolis. Other work has found no increase in sexually transmitted diseases after HPV vaccination. \u201cThe whole [promiscuity] argument is false, actually,\u201d Zimet says.<\/p>\n More likely, many parents are in denial about their teens\u2019 sexuality, says Kaufmann: \u201cParents don\u2019t believe that a 15-year-old daughter may already be sexually active.\u201d But a 2010 U.S. survey found that at least 12 percent of 14- and 15-year-old girls had engaged in oral sex or intercourse or both.<\/p>\n One way to skirt the problem might be to vaccinate earlier. Health psychologist Jo Waller of University College London says focus groups show that parents like the idea of vaccinating girls as young as age 8 or 9, since that means skipping the chat about how the vaccine prevents sexual transmission of HPV. \u201cThey wouldn\u2019t have to open that can of worms,\u201d she says. Some countries do begin vaccinating at age 9, and several trials are under way testing the effectiveness of the shots at that age.<\/p>\n The fact of the matter is that the science underlying the HPV link to cancer is unassailable. German scientist Harald zur Hausen discovered the connection in the 1980s and was awarded a 2008 Nobel Prize for his efforts (SN: 10\/25\/08, p. 10). While Pap smears have averted most deaths from cervical cancer in the United States, the malignancy remains a leading cause of women\u2019s cancer worldwide. Three shots of Gardasil or Cervarix protect against HPV types responsible for 70 percent of cervical cancers.<\/p>\n The other half of the equation WORLD VIEW Scientists established a link between oral cancer and HPV more than a decade ago when studies revealed HPV 16 lurking in many oral tumors. In 2007, researchers at Johns Hopkins University found that oral cancer patients were three times as likely as people without the cancer to have had six or more partners on whom they had performed oral sex. But there\u2019s much still unknown about the dynamics of oral HPV transmission, says epidemiologist Marc Brisson of Laval University in Quebec. \u201cKissing may be involved.\u201d He and others thinks that changing sexual practices may be behind the rise in oral cancers.<\/p>\n HPV vaccination is now recommended for boys in the United States (SN Online: 10\/26\/11). But because approval came later than it did for girls, only about 8 percent of boys ages 13 to 17, the initial target group, got at least one shot in 2011. As with girls, 11- to 12-year-old boys are the main vaccination target. But teenagers and young adults of both sexes can get the shots as part of a catch-up effort.<\/p>\n The HPV vaccines are given to prevent genital or anal HPV infections. Vaccine companies can\u2019t make any claims regarding oral cancer because the vaccines haven\u2019t been tested to prevent it. But the evidence is strongly suggestive.<\/p>\n \u201cIt\u2019s time to start vaccinating boys,\u201d says Margaret Stanley, a pathologist at the University of Cambridge in England. Boys and young men in Britain are not yet getting the shots, but Stanley and others are pushing for it. \u201cIt will protect 50 percent of the population, and not doing so would be truly discriminatory because that would include gay men, who are very much at risk of anal cancer,\u201d she says. \u201cAnd if you vaccinate boys, you start to get herd immunity.\u201d<\/p>\n A shot at the herd<\/a>
Many U.S. mothers are reluctant to have preteen daughters vaccinated, even though that\u2019s when protection is most likely to prevent a future HPV infection.
Source: J. Kahn et al\/Pediatrics 2009<\/p><\/div>\n
\n<\/strong>Most childhood immunizations are doled out in infancy. Although preteens and older kids routinely get shots or boosters for whooping cough, measles and meningitis, the HPV vaccines stand apart from those other shots like an unpopular kid.<\/p>\n<\/a>
Health guidelines recommend the three-shot HPV vaccine for the best protection against cancer. But recipients don\u2019t always complete the regimen. Compliance is worse in some states than in others.
Source: A. Jemal et al\/JNCI 2013; Image: Geoatlas\/Graphi-Ogre, adapted by E. Feliciano<\/p><\/div>\n
\n<\/strong>While cervical cancer is the most common malignancy prevented by the vaccines, in the United States nearly two-fifths of HPV-related cancers occur in men. That\u2019s because HPV can cause cancers in the mouth or throat areas, and those strike both sexes. HPV is implicated in roughly 60 percent of oral cancers that affect the back of the tongue, throat and tonsils. Although many of these malignancies arise from alcohol and tobacco consumption, those types of cancers have declined in the United States in recent years even as overall oral cancer rates have stayed the same. HPV-related oral cancers account for the rise, particularly in men. In Denmark, the past decade has brought a shift in tonsil cancers, from 43 percent containing HPV to 75 percent.<\/p>\n<\/a>
HPV vaccines can prevent cervical cancers. Although roughly 40 countries worldwide now have HPV vaccination in their national health guidelines, few low-income countries \u2014 where cervical cancer remains a major problem \u2014 are in this group. However, pilot programs in some poorer nations indicate that the vaccine is well accepted, particularly when delivered at schools.
Source: M. Forouzanfar et al\/Lancet 2011, adapted by E. Feliciano<\/p><\/div>\n
\n<\/strong>The slow launch of HPV shots in many countries is reminiscent of an earlier campaign that also could have stopped a sexually transmitted virus and the cancer it causes. \u201cWith the hepatitis B vaccine, we essentially lost a generation,\u201d says Basil Donovan, a sexual health physician at the Kirby Institute and the University of New South Wales in Sydney. Slow implementation since the hepatitis B vaccine became available three decades ago has left the 350 million hepatitis B carriers worldwide at an increased risk of liver cancer.<\/p>\n