Beyond the vaccine scrutiny

Debunking popular myths

Immunization Awareness Week has come and gone, but many still struggle to sift through the skepticism surrounding immunization. As we are flooded with vaccination information from our family physicians, immunization campaigns, and the media, it is worth questioning how one can make a more informed and educated decision about vaccinating oneself.

A strong anti-vaccine lobbying movement has long existed. Most of the lobbying comes from a small number of groups (for example, anti-vaccine activists and religious organizations) who are concerned about changes in the prevention paradigm, or who oppose ‘big pharma.’ These campaigns are best defined as unscientific ‘noise’ as they are not grounded in scientific evidence but rather are typically based on misinformation or misinterpretation. It is this ‘noise’ that is most often diffused by the media when new vaccines are introduced into medical practice.

Many individuals often feel overwhelmed by the conflicting health information coming from news outlets regarding vaccines; a healthcare professional may say one thing while the news says another. But the crucial question to ask is: do real divergences exist in the scientific community pertaining to the vaccine a person is considering? Or is the ‘fire’ maintained artificially by a few individuals, namely the anti-vaccine lobbyists?

The introduction of the human papilloma virus (HPV) vaccine is an excellent example. The Public Health Agency of Canada has approved and recommended the HPV vaccine for everyone aged 9-26 in order to prevent cervical pre-cancers and cancers, and genital warts. In a recently published paper in the Annals of Medicine entitled “Human papillomavirus (HPV) vaccine policy and evidence-based medicine: Are they at odds?”, Lucija Tomljenovic and Christopher A. Shaw responded that, “Given the demonstrable success of regular [Papilloma] screen smears…, it is unlikely that HPV vaccination (even if proven effective against cervical cancer) will reduce mortality rates beyond those already accomplished with routine Pap screening.” Another major concern is that individuals will believe the vaccine offers long-term protection and therefore will forgo routine Pap tests.

This is an inaccurate and misleading argument. The Pap test has important limitations. According to PapScreen Victoria, Pap test may not always detect abnormal cell changes simply because they are missed under the microscope, or blood or mucus may make it hard to point out the abnormal cells. The sensitivity of the Pap test to detect precancerous or cancerous lesions is, at 55 per cent, just a little better than a coin flip – meaning that it has a 45 per cent probability of false negative results.

All scientific research suggests that the HPV vaccine is highly effective in preventing precancerous lesions. The safety data for this vaccine are among the best documented for any new vaccine. It is true that the impact of cancer rate reduction will only be measurable in a couple of decades. However, all existing scientific data points to the vaccine as an important measure of prevention against persistent HPV infection and pre-cancerous lesions. In addition, in Australia, Denmark, and Sweden, studies have already shown that use of the vaccine has led to a strong protective effect as well as a decline in genital warts in the population. Should we ignore this data and leave people at risk for HPV associated diseases or should we be proactive and prevent future diseases?

With this in mind, Alberta and Prince Edward Island have decided to include males in HPV vaccination school-based programs to stop the spread of HPV infection and ultimately disease, including HPV-related cancers in both sexes. While some have questioned whether this is a cost-effective decision, from a public health perspective cost is not the sole issue, but only one alongside others such as equity and protection of the population.

It is undeniable that many individuals have underlying concerns about vaccine safety and efficacy. One of the most common communication challenges is the misunderstanding and/or misreporting of Vaccine Adverse Event Reporting System (VAERS) data; the Quebec equivalent of this is called Effets Secondaires Possiblement Reliés à la Vaccination (ESPRI).

Michelle Booth, in an article for The Gazette entitled “Questions about Gardasil,” reported that “according to the Public Health Agency of Canada…600 adverse reactions to the vaccine, including 22 hospitalizations and one death” are related to HPV vaccination. This claim is one of the most classical misinterpretations of reported safety data. First, a reported adverse event (even after vaccination) does not mean it was caused by the vaccine. Second, the author did not mention what these adverse events were. Third, Booth does not address how many non-vaccinated children of the same age were hospitalized during the same time frame. In other words, were we to compare the proportion of adverse events in a non-vaccinated similar group of children, we might find as many, if not more, ‘adverse events’ overall.

Critically dissecting the arguments and information one reads or hears about vaccination accurately can be quite difficult. It is also challenging for scientists and clinicians to explain probability and numeracy concepts clearly. What we must remember is that the pillars of the anti-vaccine circus are misinformation, misinterpretations, and a simple refusal to believe the scientific evidence.

The fear of side effects is a genuine concern, but we should not base our irrational fear of vaccines on word of mouth and speculation. Still, scientific reasoning alone is not sufficient to inform and educate the public on the matter. We need smart advocacy and knowledgeable public personas that can properly educate the public about the importance of immunization. We need to take advantage of the new tools of social media to counter the anti-vaccine ‘noise.’ We need health care professionals to take the time to explain the pros and cons of vaccination to their patients. We need to ensure that our information is coming from credible and reliable sources. We need to engage in open, honest, and healthy debates, using high quality scientific and evidence-based data to govern our discussions.

Samara Perez is a doctoral student in Clinical Psychology at McGill, supervised by Dr. Zeev Rosberger. Her area of research focuses on understanding the psychosocial factors related to HPV vaccine decision-making.