HPV vaccine: why aren’t Canadians buying in?

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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.