Human papillomaviruses are responsible for many cancers, especially cervical cancer and throat cancer. Vaccines exist for the major HPVs that cause these cancers, yet relatively few eligible youths have gotten them. Experts discuss the toll of HPV and the reasons so many people avoid both vaccination and Pap tests that can detect cervical cancer early.
- Dr. Rodney Willoughby, Professor of Pediatrics, Medical College of Wisconsin and member, American Academy of Pediatrics Committee on Infectious Diseases
- Dr. Susan Vadaparampil, Senior Member, Division of Population Sciences, Moffitt Cancer Center, Tampa, FL
- Dr. Leah Smith, postdoctoral fellow, Queen’s University
- Dr. Linda Levesque, Assistant Professor of Health Sciences, Queen’s University
Links for more info:
15-04 HPV, Cancer, and the HPV Vaccine
Reed Pence: Most people have heard of human papillomavirus, or HPV. But there are a lot of misconceptions about it. For starters, HPV is more than a single virus. There are actually about 40 types of genital HPV. As a group, HPV is the most common sexually transmitted infection in the United States, according to Dr. Rodney Willoughby, Professor of Pediatrics at the Medical College of Wisconsin and a member of the American Academy of Pediatrics Committee on Infectious Diseases.
Rodney Willoughby: HPV is a virus which is very present in humans, and is currently an epidemic really in most of the world. It tends to infect skin cells and other surface cells of the body.
Reed Pence: HPV is incredibly common. So common, in fact, that some people say anybody who’s had sex has probably had HPV.
Rodney Willoughby: It’s probably an overstatement, but the thought is that roughly half of people who are sexually reproducing have had an HPV infection or have one currently.
Susan Vadaparampil: It’s something that is typically transmitted sexually, but affects the majority of the population. So it’s not one of those things that, “Oh, it’s only those folks.” At some point, most adult men and women will have an HPV infection in their lifetime.
Reed Pence: That’s Dr. Susan Vadaparampil, a Senior Member of the Division of Population Sciences at the Moffitt Cancer Center in Tampa, Florida.
Susan Vadaparampil: I think an important thing to know is that just because you have an HPV infection doesn’t necessarily mean you’re going to develop an HPV-related disease, like cervical cancer, anal cancer, or genital warts. For most people, they’re able to clear the HPV infection and go on about their day without any problems, but there is those subset of infections that for whatever reason stick around and may lead to health problems down the road.
Reed Pence: Government figures show that by age 24, 45 percent of women in the United States have had HPV. Most will never know it. Yet HPV is the cause of about 70 percent of all cervical cancer. And the virus doesn’t discriminate based on gender, either.
Susan Vadaparampil: We’re learning much more that HPV is responsible for the vast majority of cancers that impact both men and women including anal cancer, the vast majority of anal cancers are caused by HPV infection, about half of penile cancers, slightly more than half of penile cancers. And one that’s really received a lot of attention lately are the growing rates of what we call oropharyngeal cancer, sometimes it’s referred to as head and neck cancer, and while there’s about 60% better that are caused by HPV and 40% that are not caused by HPV, the group caused by HPV is the most rapidly growing of the oropharyngeal head and neck cancers. So that again is a cancer that actually disproportionately can affect men and that’s the group that we see who are really kind of bearing the burden of that HPV-related cancer.
Rodney Willoughby: What’s particularly troublesome is that those cancers are much more difficult to treat than the same cancers when not caused by HPV, and it is in males where that has been increasing most dramatically. So now pretty much, there is probably two cancers in females for every one cancer in men. The men are catching up quickly.
Reed Pence: Many doctors say cervical cancer should be nonexistent in the United States. The Pap test, developed in the 1940s, can identify cervical cells in a precancerous state when they can be easily removed and never progress to cancer. Still, about 4,000 women in the United States die of cervical cancer each year. Dr. Leah Smith is a Postdoctoral Fellow at Queen’s University.
Leah Smith: Certainly since cervical cancer screening has been introduced we’ve seen major declines in the risk of cervical cancer, but of course there is a portion of the population that are still not undergoing Pap smears for whatever reason. And often it has to do with access, sometimes knowledge about the issue, education, those kinds of things.
Susan Vadaparampil: Pap testing is really a good example in the United States of how we’ve gotten close to population-based coverage of the test. So you’ll see in most health surveys that kind of look at the status of what’s going on with cancer screenings in the country, that rates of testing across all racial-ethnic groups, minority groups is over 80%. But there are those subsets of women that don’t engage in cervical cancer screening, and you know, it’s the usual kinds of reasons that we think about, so things like access to care, lack of knowledge or awareness of how important this is, and this is still a very, very important group to reach.
Reed Pence: The failure to reach those women as well as the increasing number of other HPV-related cancers is leading many public health experts to push for more use of the HPV vaccine, which was introduced in 2006. The vaccine was originally recommended for preteen girls, due to its ability to prevent cervical cancer. But now boys are also included in the guidelines.
Susan Vadaparampil: The way that the guidelines are currently indicated every adolescent between the ages of eleven and twelve, potentially starting as young as age nine, and up to age twenty-six for females or up to age twenty-one for males should be receiving a recommendation for vaccination. So in that case, in our study where we asked providers, “Do you always recommend vaccination?” And we asked by age group. What we saw is that the rates were far lower than what we would’ve hoped to see, which is that one hundred percent of folks are saying, “Yes, I recommend it all the time.”
Reed Pence: Vadaparampil’s survey found that for boys age eleven to seventeen, only 13% of doctors and other healthcare providers recommend vaccination. And for girls?
Susan Vadaparampil: About 40% of providers, physicians always recommended vaccines for girls aged eleven to twelve, 55% for thirteen to seventeen, and then 52% for eighteen to twenty-six. So again, only half the providers are reporting that they always recommend the vaccine. And because this is a vaccine that’s really intended for everyone, not a select group of people, but every child that’s within that age range, boys and girls, these are really rates that speak to that we have a lot of work to do to get those vaccination rates up.
Reed Pence: As it is, only 38% of girls and 14% of boys completed the HPV vaccination series in 2013, the latest year of statistics. Far short of the 80% goal of federal officials by the year 2020.
Rodney Willoughby: That’s really concerning. At the moment probably about 1 in 400 girls that a pediatrician or family practitioner sees in their practice is going to develop an HPV-associated malignancy, and it’s about 1 in 700 or so in boys. That’s a lot, a lot of kids, almost every practice could have several get this, and the fact that the take of this vaccine is under 50% means that a large number of each of these birth cohorts every year, four million kids per year born in the United States of America, at the moment half of those kids are going to go on and be unprotected, and that’s really a shame. The real issue is the missed opportunity and in particular the missed personal attestations on the part of pediatricians and family practitioners to say, “this is a vaccine that’s very important, it’s not optional.”
Reed Pence: But why have so few parents had their children vaccinated with what’s really a cancer vaccine? Well, first of all, some people think it’s simply unnecessary, at least if women are keeping up with their Pap tests. And males don’t get cervical cancer at all. But Willoughby says that’s antiquated thinking.
Rodney Willoughby: If you’re still thinking of this in an old-fashioned way as being an anti-cervical cancer vaccine then there’s no reason for the boys to get it. The boys get it because there’s also this big risk for oropharyngeal cancers, cancers of the mouth and throat. And then the other problem, which is a public health consideration, is that boys give it to girls, and if only half of the girls are getting it, then at some point you have to say, “well, we’ve got to give it to the boys so that they don’t give the HPV to the girls,” and that consideration also figured in. And all these considerations would go away, and be much simpler if people would get the vaccine at the same rate that they get other vaccines, which is up in the high 80% range. First of all, it would be almost game over for many of these cancers. We wouldn’t have to have these discussions about girls versus boys.
Reed Pence: However, Smith says the biggest factor in keeping HPV vaccination rates low is probably the age when the vaccine is recommended to be given.
Leah Smith: So this is a preventive vaccine, so it’s meant to be given before an individual ever becomes infected with HPV, and as we know HPV is a sexually transmitted infection, and so the goal is really to administer this vaccine before the onset of sexual activity, so that the probability that the individual has been infected or come into contact with HPV is still low. So when the vaccine first came out, for example, it was highly recommended for young women aged nine to fourteen years, so really in those young, pre-teen ages when their probability of sexual behavior is still low.
Rodney Willoughby: The age for the vaccine was chosen to correspond to ages pretty much nine to twelve, and that is a time when most, but not all children, have not initiated sexual activity of any form including kissing, and therefore it’s the perfect time to vaccinate against the virus. Once you’ve acquired the infection the vaccine doesn’t help at all, so it needs to be done then.
Reed Pence: However, giving preteens a vaccine for a sexually transmitted disease seems to a lot of people like giving a license to be promiscuous, a license they’d rather not give.
Leah Smith: I think that’s been a common concern, not just with the HPV vaccine, but with other sexual health-related interventions. We hear the same sort of debate with respect to, for example, school-based condom programs or sexual health education programs. And so there’s always this concern that by giving individuals knowledge about sexual health that it might be given as sort of a green light to become sexually active, so it’s really not surprising that this concern has come up again with the HPV vaccine.
Reed Pence: However, Vadaparampil cites a recent study involving more than a quarter-million girls that shoot down that concern. The study was done by Smith and Dr. Linda Leveque, also of Queen’s University.
Susan Vadaparampil: Now we have the data and the studies that show that in fact that is not the case, and that vaccinated teens are no more likely to participate in high risk or any sort of sexual behaviors compared to their unvaccinated counterparts. So I think if parents or providers are concerned about sending that message, that doesn’t seem to be the message that the adolescents are receiving, and we now have some really good data to support that.
Reed Pence: Cost concerns and insurance hang-ups may prevent that in the United States, but Vadaparampil says some measures we could take are free. For example, public health officials have to steer the discussion of the HPV vaccine away from its prevention of a sexually transmitted disease. Instead, she says, call it a cancer vaccine.
Susan Vadaparampil: I think that’s really where every expert, and I think the successful vaccinators have really come to a point of consensus, is that we need to emphasize the cancer prevention benefits of this vaccine, and take it out of the realm of sexually transmitted infections, and implying high-risk behaviors, etc. But really having a message that resonates with parents of, “if there were a vaccine to prevent cancer in your child down the road would you vaccinate your child?” I think that’s a message that parents understand, that they would respond to, and providers give the information in such a way that it really points to those benefits.
Reed Pence: However, if vaccination rates start to substantially climb, it might change who it makes sense to vaccinate. Leveque says maybe then, we can stop vaccinating boys.
Linda Leveque: The cost-effectiveness studies that have been done for boys in the committing context indicate that it’s most likely not cost-effective to vaccinate boys, if the use of the vaccine is in the range of approximately 80% for girls. And the presumption there is that in a heterosexual couple if the girls are not carrying the virus, by virtue of being vaccinated, then they’re not passing it on, and with time the viral load circulating will become very small to nonexistent. So that’s the principle behind many vaccines.
Reed Pence: However, while public health officials are trying to boost immunization rates, which vaccine will they recommend? Late last year, the FDA approved a new vaccine that covers nine HPV viruses, rather than the four major viruses covered by the current vaccine. It’s the kind of uncertainty they don’t need if they’re trying to keep the message to parents simple and understandable. What they need to know is this, HPV causes thousands of cancer deaths in the United States each year, and in the future, those tragedies could become completely preventable, if kids are given the vaccine.
I’m Reed Pence.
Sign up to receive email updates
Enter your name and email address below and I’ll send you periodic updates about the podcast.