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The Dose Transcript for February 6, 2025

Host: Dr. Brian Goldman

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BRIAN GOLDMAN: Hi, I'm Dr. Brian Goldman. Welcome to The Dose. The World Health Organization says cervical cancer is the fourth most common cancer in women. That's the bad news. The W.H.O. also says we could witness the complete elimination of cervical cancer by the year 2030, thanks to vaccines that prevent the two strains of human papillomavirus or HPV that cause the cancer. That achievement, though, comes amidst a cacophony of negative talk on social media about vaccines in general, including HPV vaccines. So, this week we're asking: What do I need to know about HPV, and HPV vaccines? Hi, Deborah. Welcome to The Dose.

DEBORAH MONEY: Hi, Brian. Thanks for having me.

BG: In the Annals of Cancer Prevention, how big a deal is the HPV vaccine?

DEBORAH MONEY: It's extraordinary. I mean, we have a situation where we have a vaccine-preventable cancer. That's just an amazing achievement for the world if we could deliver on that opportunity.

BG: That's something that the W.H.O. is very keen on trying to develop, not just in countries like Canada, but around the world. And so, we're going to talk about HPV and HPV vaccines. But before we begin, can you give us a, "Hi, my name is," tell us what you do and where you do it.

DEBORAH MONEY: Hi, my name is Dr. Deborah Money, and I'm a professor at the University of British Columbia and head of the Department of Obstetrics and Gynecology. Thank you for having me on.

BG: Looking forward to our conversation. Let's begin with HPV. What do we need to know about human papillomavirus?

DEBORAH MONEY: Well, I think as the name suggests, obviously it's a virus. It's what we call a DNA virus. Pretty much every virus that infects humans, as you know, have certain places that they like to infect. So, we have the coal tending to do our throat and our lungs sometimes. We've got hepatitis viruses that tend to go for the liver, that in the case of the human papilloma virus, it particularly likes skin. And the one that we're talking about today and thinking about is those strains and in fact the genital area. So, the vulva in the vagina and the cervix, which is the important one for women and also can affect other parts of the body as well.

BG: You know, since HPV is considered a sexually transmitted infection, people acquire it through sexual contact. Is it the full depth and breadth of sexual contact?

DEBORAH MONEY: Well, it's actually skin-to-skin contact that is obviously a major part of sexual encounters. But what's important to know is, for example, condom use can reduce exposure, but does not eliminate the risk of HPV, because HPV is on all of the skin of the genital tissue. So, can be on the, on the surface of the female genitalia, and on the surface of the male genitalia. So, skin-to-skin in a sexual encounter is the primary way of HPV being transmitted.

BG: How prevalent is HPV infection across the entire population?

DEBORAH MONEY: Hugely prevalent and very, very common virus. And most individuals will be exposed in early sexual encounters. And then over a lifetime, the vast majority of individuals will have had an HPV infection. But the good news is that, in fact, for most people, it's a transient infection, and it's cleared and, and it just goes away. And so, the only real worry with HPV is when it persists and causes either in some cases benign warts, which can be really problematic, or in the case of what we're talking about today, persists and then, actually converts to a cancer-causing virus.

BG: Does the prevalence of HPV infection differ between men and women?

DEBORAH MONEY: Not much, actually. In the end, over lifetime, both men and women are exposed to, and have at least usually a brief infection with HPV. We tend to focus on women because of the concern with cervix cancer. And almost all cervix cancers are caused by an HPV infection. But in fact, men also carry and can be infected and affected by HPV.

BG: I kind of skated over the question or you briefly mentioned it, but I want you to talk about it in a bit more detail. What are the symptoms of HPV?

DEBORAH MONEY: Well, I think probably importantly, the most common one is, is no symptoms. And that's actually why it's problematic. So, people often aren't aware that they have an HPV infection, and they will have sexual encounters with each other and pass the virus along unknowingly. If it is to cause symptoms, the symptoms of two of the strains, 6 and 11, are not the cancer-causing types. They can cause nasty warts, and warts are basically extra protrusions of warty tissue that can be tiny or can be quite large and quite bothersome for people. But the ones that cause cancer that affect the cervix or other tissues, those are actually quite silent, so people aren't aware.

BG: So, what's the connection between HPV and cervical cancer?

DEBORAH MONEY: Well, that's what's so extraordinary. And we've got very few cancers that we know about that absolutely require a virus to cause them. So, 99 per cent of cervix cancers are caused by one or more of the cancer-causing strains of human papillomavirus. But the majority of HPV infections don't lead to cancer.

BG: That's cervical cancer. Are there other cancers that are caused by HPV infection?

DEBORAH MONEY: Yes, there are. They're just not as exclusively caused by HPV. So, anal cancer is very much associated, about three quarters are associated with cancer-causing HPV. We have penile cancer. We have vulvar cancers. These are more rare, and they don't always require HPV. And then, we have head neck cancers, which have been actually very difficult to screen and manage. And some of them are also caused by HPV.

BG: Depending on their sexual practices, can anyone get these kinds of cancers?

DEBORAH MONEY: Essentially anyone, unless you have absolutely zero physical contact with other humans. But pretty much most individuals in one way or another. Males with males, women with women, other gendered individuals. The exposure is skin-to-skin and the virus is ubiquitous. So, the bulk of the population essentially are at risk for this infection.

BG: The reason why I asked that question is that it's very easy to try and identify high risk groups that are particularly prone to these kinds of cancers. Is that relevant?

DEBORAH MONEY: Not really, for the strategies that we want to deploy. There are some individuals who are a bit more likely to get HPV. You know, the more sexual partnerships you have, the more numbers of sexual encounters, sure. But really, to be honest, it's such a common virus that, that is unhelpful to do that. And it's unhelpful to sort of label it excessively as a sexually transmitted infection in that way. We understand that's the way it's passed, but there's no way a person can have a very limited sexual encounters in their life, and still acquire this virus.

BG: How has the strong link between HPV and cervical cancer changed Canada's cervical cancer screening guidelines?

DEBORAH MONEY: We've had a long, long history of very successful cervical cancer screening with something that I think most people know about: the Pap test. So, the Pap test is where, with an internal gynecologic exam, the speculum exam, small sample of cells are taken from the cervix, looking to see if there's pre-cancerous changes in those cells. And that's been in place certainly here in British Columbia. We were the first province to initiate population-wide screening in the mid-1950s, and then, many provinces came on quite quickly. And so, we've had a country where access to Pap smear screening has been general for everyone. That's been an amazing tool to reduce invasive cancer. But the new opportunity is to back up another way down the path and say, "Well, let's not wait till we start to see cervix cells changing and getting precancerous. Let's actually figure out whether somebody has one of the cancer-causing viruses in their system. And if they don't, they have an extraordinarily low risk of developing cervical cancer. And if they do, then we can put them into other screening and testing pathways."

BG: What are the tests that are available to detect HPV?

DEBORAH MONEY: There's several, many strains that most of the testing programs test for a family of cancer-causing viruses. So, what's been launched in British Columbia and P.E.I. is a population-level HPV swab can be done as a self-swab of the upper vagina. Or a practitioner-taken swab. And that has been launched in two provinces as primary screening. Other provinces use the HPV test as an additional piece to the Pap smear. But I believe that most of the provinces will convert to primary HPV screening because that's actually been shown to be the most sensitive way to pick up and reduce cervical cancer.

BG: I'm thinking about instances where there's a risk for anal cancer or for head and neck cancers. Can you do a throat swab, for instance, or an anal swab?

DEBORAH MONEY: You can do an anal swab, and that is being considered as a screening possibility. Anal cancer is not quite as straightforward in its pathway to cancer. Anal cells can look abnormal, but they don't kind of have quite the same prognosis for cancer that the cervix cells do. Because HPV is so common, it's a bit challenging with anal HPV swabs. They're being brought in not across the board, but they are definitely something that are being investigated. But they can be done. Absolutely. The throat swabs have not yet proven to be something that would be a value in a screening situation. They are, often, will test for the virus in cancer samples. But head neck is, is proving to be a more challenging set of cancers to try to evaluate.

BG: Is there an out-of-pocket cost for HPV testing?

DEBORAH MONEY: Not in B.C. or P.E.I. And if it's reflex tested in other provinces, no, but if you, say, are in Ontario and you just want to test, then there is an out-of-pocket cost for that at the moment. Although, I think that's going to change soon.

BG: Let's talk about HPV vaccines. What options are available?

DEBORAH MONEY: To, you know, back up with the understanding of the fact that cervix cancer is essentially almost exclusively caused by a virus. Many years ago, there was the notion that, well, if we had a vaccine against this virus, then people wouldn't get it at all in the first place. And wouldn't that be amazing? Well, to our perhaps surprise, actually, the HPV vaccine development has been extraordinarily successful. The companies that have put these vaccines into market have come up with a capability to generate basically a empty shell of proteins. So, the surface of the virus is made up of proteins. And the HPV vaccine is actually a sphere. It's like a protein ball with no active virus DNA inside. So, what it does is it doesn't cause harm because it's just a protein ball essentially, but the body looks at it and goes, "Oh, you look just like a virus." And so, they make really good antibodies against HPV. So, we now have vaccines available that actually have almost all the cancer-causing strains and the wart-causing strains in the vaccine formula. And that vaccine can be delivered to individuals at an age before they start getting exposed to HPV vaccine and it can prevent acquiring the infection. So, it's a prevention vaccine, not a treatment vaccine.

BG: And there's more than one vaccine manufacturer who is making HPV vaccines. Am I right?

DEBORAH MONEY: Yeah. Primarily Merck and GSK. GSK went with a 2-valent vaccine, which is 16, 18, which are the most common causes of cancer. And Merck has decided to go with a 9-valent formulation, which means they include the wart causing one, 6 and 11, and seven other cancer causing ones, which also include 16 and 18. So, for the most part, Canada has gone with the 9-valent product because it was felt to be the most valuable for people.

BG: And how effective are these vaccines at preventing HPV infection?

DEBORAH MONEY: Well, that's what's extraordinary. They're much more effective than many of the vaccines we use. They're over 90 per cent effective.

BG: I read recently there was a paper in the Canadian Medical Association Journal in 2024 that suggested that one dose might be sufficient. How many doses are we generally talking about?

DEBORAH MONEY: So, the initial vaccines were tested with three doses. So, a 0 to 6 months strategy. And that was based on sort of general vaccine, prime and boost approaches. But that's actually quite expensive and sort of logistically complicated to deliver free time points and reminders and all that business. So, there was a lot of work looking at two doses in zero, six-month. And then more recently, one dose. And it looks like, in fact, that the one dose for this particular vaccine, because of its very nature, may well be sufficient. And the data that we have strongly supports that one dose is sufficient. And what it's going to allow for, particularly in other parts of the world, where this is almost a unachievable goal because vaccines are expensive and delivery is expensive, that the one dose is possibly going to be achievable globally as well as in Canada.

BG: How do Canadians get the HPV vaccine in this country? And I'm sure that the distribution varies with the province. But what can you tell us about that?

DEBORAH MONEY: With minor variations, what we have is we have a school-based program where it's actually at a pre-teen age, sort of 9 to 11 is the ideal. But each province has [inaudible] want to do in Canada is a little bit different in how they deliver, that the differences are relatively minor and related to just vaccine programing, not related to differences in, in effect really. And so, what we have is the opportunity for school-based children, girls, and boys to have a free vaccine available. And globally, it's been found that that is the absolute best way to deliver vaccines at a population level, childhood vaccines. So, so, that's what's available free. And then, there are some select catch up programs, but vaccine is certainly been proven to be effective and safe right the way through to age 45. And to be honest, it's likely fine beyond that. But those are the age limits that have been studied so far.

BG: You mentioned the school-based programs. What about what about people who aren't going to school, aren't in the public education system at this point in their lives?

DEBORAH MONEY: So, if they fit in one of the individual, provincial-funded examples, and there's quite a list of them in each province, and those are available on websites. But then, public health. Public health's office could deliver the vaccine free of charge. And if not, if they're outside of the publicly funded program, one can simply get a prescription for the vaccine and have it delivered at a clinic.

BG: I want to talk about the other side. On social media, there's a lot of criticism of HPV vaccines. What do you make of that?

DEBORAH MONEY: It's, makes me sad, to be perfectly honest, because it is misinformation. It is simply not true. This vaccine has been proven in hundreds of thousands of doses around the world to be an extraordinarily safe vaccine. We have seen really dreadful examples of misinformation resulting in countries like India having a hugely delayed program. Japan had their program delayed by literally storytelling. They were amplified, and simply were not based on truth. The vaccine causes a sore arm in young kids that get very nervous about the vaccine. Sometimes, they will faint associated with getting a vaccine because it's a needle in the arm, and it's scary, and it's distressing. But in terms of actual side effects related to the vaccine product in your body, changing fertility, changing other things, changing risks of pregnancy, adverse pregnancy outcomes, all sorts of non-sense has been out there. It's simply just not true.

BG: And I think we can say fairly safely that, that HPV vaccines do not cause cancer.

DEBORAH MONEY: Absolutely. They cannot cause cancer. They are simply a protein shell. They don't have the active DNA of the virus that is the thing that causes cancer. And so, they are extraordinarily safe.

BG: Do you think it's easier for there to be criticisms raised about this particular vaccine or these particular kinds of vaccines against HPV infection simply because they're relatively new? They're certainly not newer than COVID, but they're more recent than many of the other traditional childhood vaccines.

DEBORAH MONEY: I think it's a combination of that, and the fact that it has also about sort of sexual activity stigma associated with it. I think as we all made recommendations for roll out, it was probably, I think, people were so in the medical community and public health community, there was so much excitement over the fact that this was a cancer prevention vaccine and a desire to get it out as, as soon as we possibly could, that there perhaps wasn't, in retrospect, enough preparation and education around what the virus was, what the vaccine did. And then, for pragmatic reasons, it was rolled out in girls, not boys. And then, that people kind of thought, well, where is that? Why is it just the girls? And it was inadvertent, but many different reasons have resulted in it maybe being a bit more susceptible to misinformation than the other, maybe more boring, I suppose, childhood vaccines.

BG: Perhaps the education system can take some steps to address whatever residual information gap remains. But this is, bottom line, a good news story. And Dr. Deborah Money, I want to thank you for coming on The Dose to talk to us about HPV, cervical cancer and HPV vaccines.

DEBORAH MONEY: Thank you very much for having me, and thank you for your interest in this important topic.

BG: Dr. Deborah Money is a professor and head of the Department of Obstetrics and Gynecology at the University of British Columbia. Here's your dose of smart advice. Human papillomavirus, or HPV, is a virus that can infect many parts of the body. There are more than 100 types of HPV. It's one of the most common viral infections. More than 70 per cent of unvaccinated sexually active Canadians are believed to have had an HPV infection at some point in their lives. HPV can affect everyone regardless of gender or sexual orientation. The virus is called a sexually transmitted infection, which is true in practical terms. In fact, the virus is transmitted through prolonged skin-to-skin or skin-to-mucous membrane contact, especially during intercourse, oral sex, and anal sex. In most people, HPV causes no symptoms. Some people infected with the virus develop warts in the genital area, but these may develop months or even years following an infection. Most people infected with HPV recover completely. Certain subtypes of HPV, for instance, HPV 16 and HPV 18 can cause persistent infection and increased risk of cervical cancer. Those high-risk types of HPV infections cause more than 99 per cent of cervical cancers. HPV also plays a role in the development of cancers of the anus, penis, throat, head and neck, vulva and vagina. Prior HPV infection can be detected through DNA testing. In Canada, HPV tests are used in conjunction with Pap tests to help determine the risk of cervical cancer, and the need for further testing. There are currently no HPV DNA tests approved for men. Using condoms can decrease the risk of HPV infection, but does not eliminate the risk. There are now several HPV vaccines approved in Canada. Both the Gardasil and Gardasil 9 vaccines and the Cervarix vaccine protect against those two HPV subtypes, 16 and 18, which are responsible for roughly 70 per cent of all cervical cancers. Gardasil and Gardasil nine are approved for use in females ages 9 to 45 and males ages 9 to 26. Cervarix is approved for use in females ages 9 to 45. At this time, Cervarix has not been approved for use in males in Canada. Public health officials and regulators, including Health Canada, say HPV vaccines are safe and effective at preventing HPV-related infections and cancers. The most common side effects of these vaccines are pain, redness, or swelling in the arm where the shot was given, fever, headache, or feeling tired and nausea. If you have topics you'd like discussed or questions answered, our e-mail address is: thedose@cbc.ca. If you like this episode, please give us a rating, and review wherever you get your podcasts. This edition of The Dose was produced by Samir Chhabra, our senior producer is Colleen Ross. The Dose wants you to be better informed about your health. If you're looking for medical advice, see your health care provider. I'm Dr. Brian Goldman. Until your next dose.

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What do I need to know about HPV and the HPV vaccine? - Transcript

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