HPV vaccine: why aren’t Canadians buying in?Monday, June 10 2013
By Lyba Spring
In March 2007, the Government of Canada allocated $300 million over three years to carry out a provincially-run school-based program across the country to vaccinate girls against four strains of Human Papillomavirus (HPV). It is now long past the three-year mark and provincial governments continue to implement and fund these programs. Yet, the number of children immunized falls far short of their expectations.
According to an October 2012 Globe and Mail article, 30 to 40 per cent of girls eligible to receive the vaccine do not get immunized. A Queen’s University study on acceptance in Ontario found that “49.3 per cent of girls from 21 public health units refused HPV immunization between 2007 and 2011.” In sharp contrast, in British Columbia, close to 70 per cent of Grade 6 girls were immunized during the 2010 to 2011 school year. And in Alberta, which offers the vaccine starting in Grade 5, roughly 60 per cent of eligible girls received the vaccine each school year. Surprisingly, for a similar school-based vaccine program against Hepatitis B, which is also sexually transmissible, participation is over 90 per cent.
HPV is a common virus. There are over 100 strains, about 40 of which infect the genital and reproductive tract, making HPV the most common sexually transmitted infection (STI) in the world. Of these 40 DNA types, some are considered high-risk; that is, if they persist in the presence of co-factors they can cause cancer. The most common cancers caused by high-risk HPV are cervical and anal cancers, but they can also cause penile cancer, which is rare, as well as vulvar, vaginal and “head and neck” cancers. The other HPV types are low-risk, meaning that they can cause genital warts. While genital warts are a nuisance, they often resolve without treatment. For the majority of people (up to 90 per cent) infected with high- or low-risk types, their immune system will clear the virus in one to two years without medical treatment. People acquire HPV through skin-to-skin contact. This means unprotected vaginal or anal sex as well as non-genital contact. Frequency of transmission by oral sex is still unknown; the potential for transmission from fingers is unclear.
Mouth and throat cancers are on the increase despite an overall decrease in the use of tobacco and alcohol—both known contributors to oral cancers. Oncogenic (or cancer-causing) HPV is associated with many of these new cancers. Although there is speculation fuelled by recent popular media that there is a direct association between oral cancer and the number of oral sex partners, research on this issue is inconclusive. Regarding the value of HPV vaccination, in an article in the Journal of the American Medical Association in 2012, Dr. Hans P. Schlecht comments that "it will be decades before any potential benefit of HPV vaccination in reducing the rates of HPV-related cancers, such as oropharyngeal cancer, is seen." Despite what we are hearing in the media, a number of key questions have not yet been answered conclusively on this issue.
Only one year after the HPV vaccine program began, a cancer advocacy group asked, “Are we hitting the mark?” When pharmaceutical companies and public health agencies ask that question about a vaccine, it is usually with a view to increasing the uptake.
According to the media, parents have expressed two sticking points: the fear of vaccine side-effects and potential that the vaccine would encourage early sexual activity. Yet, when I was asked directly by parents about whether their daughters should get the vaccine, they showed interest in the facts about the virus; in particular, the way that the immune system usually clears it with no intervention. They also wanted to know whether a booster shot would be needed. It is true that some Catholic school boards have raised concerns about promoting early sexual activity; and anti-vaccine groups have inevitably raised questions about vaccine safety. However, there is no evidence about the former; and recently, the Public Health Agency of Canada wrote at length about the latter.
This very public, ongoing debate over HPV vaccines is confusing, passionate and often carried out in the absence of basic information. It is no surprise that both parents and young adults find it difficult to make sound health decisions around vaccination.
As a sexual health educator and women’s health advocate, what concerns me is the allocation of funding for a massive vaccine program supposedly to prevent cervical cancer and genital warts through the prevention of HPV; but this strategy remains to be proven, even though the vaccines certainly do prevent infection. Women’s health advocates questioned this funding at the outset, asking why the vaccine was privileged over other means of primary prevention of transmission of the virus, and the secondary prevention of cervical cancer.
Prevention – old school
Condoms (male and female) are an effective barrier to HPV for the parts of the body they cover. Surprisingly, it took several years for Government of Canada literature to clarify their usefulness in preventing HPV transmission. Some local health units in Ontario still maintain condoms are not very effective; or they ignore condom use altogether as a means of prevention (see fact sheet). This inadequate information is a barrier to obtaining informed consent when infection “prevention” is made synonymous with “vaccination.”
Another approach for preventing cervical cancer has been to encourage young people to postpone higher risk sexual activity. Progressive sex education offers alternatives to vaginal intercourse for heterosexual teenagers who want to explore their sexuality with a partner through kissing and touching. The rationale is cervical immaturity. It takes until at least age 18 for stronger (and protective) squamous cells to replace more vulnerable columnar cells on the cervix. A third form of protection suggested by some public health agencies is not smoking, because nicotine can be a factor in the development of cervical cancer.
Some might consider these prevention strategies ineffectual in comparison with vaccines. However, this does not explain the urgency to implement the nation-wide vaccine program in 2007.
Selling vaccines as prevention
Two vaccines were approved by Health Canada for use against HPV infection: Merck-Frosst’s Gardasil in 2006 and GlaxoSmithKline’s Cervarix in 2010. Gardasil protects against four types of HPV: 6 and 11, which cause the majority of wart infections, and 16 and 18 which are linked to most cases of cervical cancer. Cervarix protects against types 16 and 18. (There are other HPV types associated with cervical cancer that are not covered by either of these vaccines).
Messages to the public from both pharmaceutical companies and public health advocates about what this protection means are often oversimplified. The standard argument goes like this: Women needlessly die from cervical cancer. Cervical cancer can be prevented by vaccinating young girls. Warts are ugly and stigmatizing and their treatment is costly. Warts can be prevented by vaccination.
The Society of Gynecologists and Obstetricians of Canada (SOGC) created HPVinfo.ca to “spread the word not the disease.” The site provides information on signs and symptoms, health complications and risks, prevention and treatment. Yet, they stigmatize warts and, like other agencies, present the prevention of HPV infection as cancer prevention.
The early provincial ads in Ontario (Girl Talk showed young women discussing the vaccine: “Actually, I’d rather get a needle than get HPV. Did you know that three out of four kids will get HPV when they grow up and HPV is the main cause of cervical cancer?”
Ads from the pharmaceutical companies used scaremongering and parental guilt in their key messages. For example, the “One Less” campaign implied that parents who did not allow their daughter to be vaccinated were bad parents, similar to flu vaccine campaigns. And yet, current science calls that strategy into question as well.
Do HPV vaccines live up to their promise?
In December 2011, Canadian researchers Lucija Tomljenovic and Christopher A. Shaw published anessay online in the Annals of Medicine stating that HPV vaccine policies were “at odds” with evidence-based medicine. They conclude that vaccination policies need to be more evidence based and that women need to be fully informed of benefits and risks before having the vaccine. In aMedscape Medical News article, Roxanne Nelson, writes about the essay and summarizes the researchers’ statements:: “Both vaccines very effectively prevent persistent infections with high-risk HPV types 16 and 18 and the associated cervical [lesions]” in young women who have never had HPV. However, “even persistent HPV infections caused by high-risk strains generally do not lead to precursor lesions in the short term or to cervical cancer in the long term.” With up to 90 per cent of HPV infections resolving spontaneously within two years, even among those that remain, only a small proportion progress to a malignancy. Even high-grade cervical lesions (cervical dysplasia) can resolve over time.
Diane Harper, professor of Medicine at the University of Missouri, was a lead researcher in the development of HPV vaccines and involved in clinical trials for both vaccines. In an interview in January 2012 for Medscape Medical News she raised the issue of the duration of protection.
Harper explained that HPV vaccines must maintain a near 100 per cent efficacy for a full 15 years, at a minimum, for cervical cancer to be prevented. “If we vaccinate 11- and 12-year-olds and Gardasil only lasts 10 years, then 21- and 22-year-old women are no longer protected.” She had discussed this issue as early as 2009 in an article published in Current Opinion in Obstetrics and Gynecology. “No substantial public health decrease in cervical cancer will occur until at least 70 per cent of the female population is vaccinated and then the maximal reduction will not be seen until there has been continuous protection in at least 70 per cent of the female population for at least 60 years” [my emphasis].
Consider the 70 per cent reduction of cervical cancer in industrialized countries in the past 50 years since the introduction of Pap tests.
In January 2012, an update on HPV vaccines, referred to above, was issued from the National Advisory Committee on Immunization (NACI) and posted on the Public Health Agency of Canada (PHAC) website. They acknowledge there are still some unknowns, most notably, how long protection lasts and whether a booster will be needed. In terms of immune response, the report states “the immune correlates of protection against HPV infection/disease are unknown at this time”; it is, however, true that the vaccine will offer higher protection against future HPV infection than a person’s own immune system would after clearing one.
The question of immune response is important in light of Diane Harper’s question about the public health benefits. Because most cervical cancers (67 per cent) occur in women aged 30 to 59, with the average age at diagnosis being 47, it is worth noting that the PHAC report states: “studies have shown that while peak risk for HPV infection is within the first five to 10 years of the first sexual experience, a second peak” in infections is observed in women 45 and older. If these are new infections, will these women still be protected? Current Merck-Frosst ads target adult women up to age 45.
There is some good news for vaccine proponents on this front. For women who had already had one bout of HPV-related disease, a March 2012 study published online in the British Medical Journalrevealed that the HPV vaccination substantially reduced the risk of developing HPV disease in the future.
Have questions been answered?
Back in 2007, Women and Health Protection and the Canadian Women’s Health Network (CWHN) responded to the announcement of a national vaccine campaign by raising questions, in particular about what they considered to be the premature nature of the campaign. A year after the first paper, they insisted there were still unanswered questions (see article in Network). To assist beleaguered parents in their decision-making process, they published an educational fact sheet.
The 2007 statement questioned the haste with which the government implemented this very expensive program, particularly given the drop in the incidence rates of cervical cancer in Canada since the introduction of cervical Pap screening. In fact, more recently, Swedish researchers founddetecting cervical cancer early with Pap smears improves the survival rate.
While any case of cervical cancer is cause for concern, then, as now, there was no epidemic of cervical cancer. In 2011, the Canadian Cancer Society listed four cancers as accounting for 54 per cent of all cancers diagnosed in Canada. Cervical cancer was not amongst them. In 2011, there were 1,300 new cases of cervical cancer representing seven cases per 100,000.
In an interview she gave to Maclean’s magazine in 2007, shortly after the introduction of the vaccine program epidemiologist Abby Lippman noted that the women who are most affected by cervical cancer in Canada do not have adequate access to regular Pap screening, follow-up and treatment. This is especially the case for marginalized, Aboriginal and poor women. According to a2009 report from the Assembly of First Nations “participation in these [Pap screening] programs is lower for First Nations than for the general population in nearly all areas of Canada.”
The role of Pap tests and follow-up
Even without vaccination, cancer of the cervix is considered to be one of the most preventable cancers because of the high success rate when lesions are caught by Pap testing and treated in time.
Pap testing detects abnormal cells. A common abnormal result is Atypical Squamous Cells of Undetermined Significance (ASCUS). Or a woman may be diagnosed with a Low-Grade Squamous Intraepithelial Lesion (LSIL). Healthy non-smoking women under the age of 30 with ASCUS or LSIL are likely to see a subsequent normal Pap result. Because the benefit of screening younger women is so small, 2013 Canadian Pap test guidelines recommend starting at 25 and then continuing every three years. There have been a number of suggestions for the best way to integrate HPV DNA testing, including identifying the strain before regular Pap screening begins. This testing, as it becomes more available and integrated into the screening process, will reduce the number of unnecessary colposcopies and treatment, since it recognizes the high-risk strains of the virus. This too, will cost money.
The final question
Does current research support the continuation of the vaccination program?
The PHAC paper acknowledges that while the vaccine appears to be effective for 10 years, “only long-term surveillance of vaccinated populations can determine the population effectiveness of vaccination.”
They admit that “as with any vaccine recommendations, it should be noted that provinces and territories should consider additional criteria such as economic, local programmatic/operational, and societal factors when considering inclusion of [their] recommendations in publicly-funded immunization programs.”
Yet there is no national evaluation of the strategy, presumably because this massive experiment requires decades for results to be known and published. Public health strategies must be cost effective and address priority health needs. They must also consider “lost opportunity” costs—those programs that are unfunded because of others that are. Women’s health advocates have lobbied for decades for broader access to Pap screening, follow-up and treatment. With the advent of self-testing techniques, developing countries (as well as women living in remote areas of Canada) may at least see some improvements.
What is shocking is that despite the absence of a global evaluation for the vaccine program for girls, the lobbying to vaccinate boys began in February 2012, when the Federation of Medical Women of Canada called on the federal government to cover vaccination for boys. In April 2013, Prince Edward Island decided to extend their program to Grade 6 boys. The SOGC applauded this move and wrote to the Ministers of Health of every province and territory in Canada to urge them to follow Prince Edward Island’s lead and include boys in their school-based programs starting in fall 2013. Yet, the most recent information published in the PHAC report about how vaccinating boys might affect cervical cancer rates reveals “there are currently no studies that directly demonstrate reduced transmission of HPV vaccine-types from males to females, or reduced cervical cancer, as a result of immunization of males.”
Canadians deserve honest, straightforward information about the prevention of cervical cancer. Relying on an expensive program that has yet to be evaluated is questionable at best.
Lyba Spring recently retired from Toronto Public Health and now runs Lyba Spring Sexual Health Education and Consulting Services in Toronto.