It is difficult to appreciate the effects of vaccines on modern medicine to their fullest extent. Despite a potentially bothersome injection schedule or the myths associated with their ingredients and adverse effects, vaccines have saved millions of lives since their inception in 1796. Vaccines are considered to be one of the ten greatest public health achievements of the 20th century, on par with motor-vehicle safety and the recognition of tobacco as a health hazard. Akin to seat belt requirements, or anti-smoking campaigns, the widespread use of vaccines has been met with controversy.
Vaccines administered to infants or young children during the past two decades are expected to prevent 322 million illnesses, 21 million hospitalizations, and 732,000 deaths over the course of their lifetime, according to a 2014 report from the Centers for Disease Control and Prevention (CDC). Prevention of potentially devastating illnesses among children is estimated to save $295 billion in direct costs, such as medical expenses, and an additional $1.3 trillion in societal costs. However, skepticism of vaccine safety — and fading memories of vaccine-preventable diseases — have led some parents to become hesitant to vaccinate their children. “For a lot of people, they perceive that the risk is gone,” said Dr. Brian Ward, a researcher in the field of immunization at McGill, “and so they start making calculations on what’s the risk of the vaccine versus not getting the vaccine. And for them the risk of not getting the vaccine is zero. So they are comparing the very tiny risks of the vaccine to nothing.”
Only three Canadian provinces have legislated vaccination policies, which strictly applies to children starting school. Ontario and New Brunswick require vaccination against diphtheria, tetanus, polio, measles, mumps and rubella, while Manitoba requires a measles immunization. In each case, however, the legislation includes an exemption clause on the basis of conscience, medical or religious grounds.
In 1796, Edward Jenner, a rural British doctor, observed that in accordance with local folklore, milkmaids were protected from smallpox after naturally suffering cowpox. Jenner theorized that cowpox not only protected people against smallpox, but can also be deliberately transmitted from one person to another as a novel tool for conferring protection. To prove his theory, Jenner injected eight-year-old James Phipps with pus taken from a cowpox pustule on the hand of a milkmaid. The boy developed a mild fever but recovered shortly after. Afterwards, Jenner inoculated Phipps again, with matter from a fresh smallpox lesion. No disease developed, and Jenner concluded that the protection was complete. Edward Jenner had effectively pioneered the world’s very first vaccine. He submitted his findings to the Royal Society for publishing, but his findings were rejected. Instead, Jenner privately published a small booklet outlining his hypotheses, experiment, and observations titled An Inquiry into the Causes and Effects of the Variolae Vaccinae, a Disease Discovered in some of the Western Counties of England, particularly Gloucestershire, and Known by the Name of The Cow Pox.
The publication of Jenner’s inquiry was met with a mixed reaction, and he was widely ridiculed by his peers in the medical community. Although Jenner had made one of the most impactful health discoveries in history, his discovery was met with a spurious epidemic of panic and fear. Jenner’s critics, primarily the clergy, deemed it repulsive and ungodly to be inoculated with material taken from a diseased animal. At the time, satirical cartoons depicted those vaccinated with cowpox as sprouting cow’s heads, or taking on bovine features. Skepticism of vaccines remained widespread, despite lack of records entailing such side effects. Opposition to vaccination has existed as long as vaccination itself.
Albeit, the anti-vaccination movements ideology has shifted since the days of Jenner. The overall message remains the same: vaccines are dangerous and those responsible for developing vaccines are not to be trusted. Recent myths propagated by the anti-vaccination movement include: the infamous “vaccines cause autism”, safety of common ingredients, superiority of naturally acquired immunity over vaccine-acquired immunity, and the belief that vaccines are no longer necessary against disappearing vaccine-preventable diseases. Recent anti-vaccine claims seem more plausible than the myth of turning into a cow after the smallpox vaccine, however, growing scientific evidence exists debunking nearly every one.
A 1998 case series published in The Lancet, a British journal, suggested that the measles-mumps-rubella (MMR) vaccine may predispose children to development of autism spectrum disorder (ASD). Despite inadequate sample sizes (n = 12), uncontrolled design, and the speculative nature of the conclusions, the paper received widespread publicity, and MMR vaccination rates began to fall. However, immediately following the paper, subsequent epidemiological studies failed to produce the same link between MMR vaccination and autism. The logic that the MMR vaccine was responsible for triggering autism was criticized because the injection of the MMR vaccine and ASD diagnosis both occur in early childhood. Subsequently, the link between the two could simply be correlative in nature. As a result, the paper was formally retracted by the journal in 2010, citing its “failure to disclose financial interests”, as well as, “guilty of ethical violations”, and “scientific misrepresentation” on part of the original authors.
Following the MMR scare, vaccination programs started to recover its reputation. However, shortly afterwards, a new controversy regarding vaccine ingredients was popularized. Thimerosal, an organic, mercury-containing compound added to some vaccines as a preservative, became the centre of a new “vaccines cause autism” controversy. Although there is no evidence to suggest that the amount of thimerosal used in vaccines poses a health risk, leading public health, medical organizations, and vaccine manufacturers agreed to reduce or remove the ingredient from vaccines as a precautionary measure. In 2001, The Institute of Medicine’s Immunization Safety Review Committee concluded that there was insufficient evidence to prove or disprove claims that thimerosal exposure from childhood vaccines and the neurodevelopment disorders of autism, attention deficit hyperactivity disorder (ADHD), and speech or language delay were connected but “favours rejection of a causal relationship” on a more recent report. The committee did confirm that the association between thimerosal-containing vaccine exposure and neurodevelopmental disorders was biologically plausible, though not well-defined.
Despite inadequate sample sizes (n = 12), uncontrolled design, and the speculative nature of the conclusions, the paper received widespread publicity, and MMR vaccination rates began to fall.
Other common ingredients were also quickly branded as unsafe, including formaldehyde, mercury and aluminum. While these chemicals are toxic to the human body at certain concentrations, only trace amounts are found in the Food and Drug Administration (FDA) approved vaccines. Formaldehyde is produced at higher rates by our own metabolic systems than in a typical vaccine dosage. The low levels of chemicals added to vaccines do not surpass the respective recommended allowances outlined by the World Health Organization.
The anti-vaccination movement also alleges that naturally obtained immunity is superior to “artificial” immunity, as in that obtained via vaccination. In some cases, natural immunity, which refers to actually contracting the disease, results in a stronger immunity than a vaccination. However, the dangers to this approach far outweigh the potential benefits.Vaccines interact with the immune system to produce an immune response similar to that resulting from natural infection, but do not cause disease or put an individual at risk of its associated complications. Risks of acquiring immunity through natural infection include intellectual disability from Haemophilus influenza type b (Hib), birth defects from rubella, liver cancer from hepatitis B virus, or death from measles. In Canada, to gain natural immunity through contracting measles, one wagers a 1 in 1000 chance of death from the disease, and a 1 in 1000 risk of developing encephalitis. In contrast, an individual opting to vaccinate has zero risk of developing measles from the vaccine and a 1 in 1 million risk of encephalitis.
Fortunately, incidence rates of vaccine-preventable diseases are on the decline in most developed countries. Some vaccine-preventable diseases are declared as eradicated in North America. However, this does not mean that vaccination programmes in these areas can be eliminated. “One of my favourite [myths] is that we don’t need vaccines because these diseases were disappearing before vaccines were introduced,” said Ward, “and in terms of mortality, that is absolutely true […] but not the incidence of disease.”
Modern sanitation, improved nutrition and the development of antibiotics have contributed to the reduction or elimination of infectious diseases. Although vaccine-preventable diseases are becoming less common, the infectious agents that cause them continue to circulate in some parts of the world. In a highly inter-connected society, international travel is a common occurrence. Infectious agents are capable of crossing geographical borders, infecting the most vulnerable in nearly any corner of the world. Due to the success of immunization, Canada has not reported any cases of endemic measles since 1998. Infectious agents that boast only human reservoirs are capable of being completely eradicated, as in the case of smallpox, but until global eradication can be achieved, it is necessary to continue vaccinating against diseases that persist as potential threats to the Canadian population. However, “as a general rule, if there is an environmental reservoir, we have to vaccinate forever,” noted Ward. This applies for diseases such as polio and diphtheria, as they exist naturally in the environment and thus the risk of infection can never be completely eliminated.
There are two fundamental reasons to vaccinate: to protect ourselves, and protect those around us. Successful vaccination programs depend on the cooperation between individuals to ensure an overall benefit. This concept is referred to as “herd immunity,” specifically when the resistance to the spread of a disease within a population is achieved only when a sufficiently high proportion of individuals are immune to the disease, mainly through vaccination. When a critical portion or a community, typically ranging from 83 to 94 per cent, are protected against a disease, there is little to no possibility of outbreak. The concept of herd immunity is crucial to protecting those members of society that cannot receive vaccines, due to age, severe allergies, suffering from specific diseases, or are immunocompromised (diminished immune system capabilities). When vaccination rates fall below acceptable levels, members of the population become increasingly vulnerable.
Overall, the coverage rates for vaccines are high in Canada, although some fall below the minimum range to maintain herd immunity. The anti-vaccination movement further jeopardizes these coverage rates by propagating misinformation regarding the necessity of vaccination in areas where incidence rates of vaccine-preventable diseases are low. For some parents, the herd immunity argument is insufficient to convince them to vaccinate, resulting in a difficult consideration of individual risk versus moral obligation. Ward agreed: “It’s the individual harm versus the greater good that is always the dynamic around vaccine safety […] what’s the hit that you’re willing to take, in terms of these very low risks, to participate in this larger likely benefit.”
For many vaccine hesitant parents, vaccine-preventable diseases represent an unfamiliar, insubstantial threat. Many parents have simply never witnessed the potentially devastating effects of contracting measles or polio, or known someone to suffer from these diseases. Physicians and nurses in North America, despite working in the medical field, have only encountered such cases in literature. Vaccine programmes are largely responsible for a generation of parents unfamiliar with the symptoms and risks associated with infectious diseases, “we are very much victims of the success of our programs,” said Ward. Many images of disease exist only as obscure relics of the past. Long forgotten are the puffy cheeks and swollen neck of mumps, the severe diarrhea, vomiting and abdominal pain of rotavirus, or the flat, red blemishes of measles. Aside from the signs and symptoms, many of these diseases can have lasting health risks ranging from permanent deafness, brain damage, and paralysis leading to death.
The resistance to the spread of a disease within a population is achieved only when a sufficiently high proportion of individuals are immune to the disease, mainly through vaccination.
Undeterred, anti-vaccine advocates may continue to pivot the target of their accusations. The baffling longevity of the anti-vaccine movement partly speaks to its impressive malleability. “Like most myths, all of them have a grain of truth,” said Ward, “[…] they seize on the grain of truth and then extrapolate.” However, it is nearly impossible for researchers to keep up with evolving fears as they occur. Not only is studying extremely rare vaccine-associated effects difficult, anticipating them is impossible. “One of the really problematic things with vaccine-associated adverse events is that they are so rare. And so it is actually really hard to study something that is so rare,” said Ward. Take for example a new vaccine that has an unknown serious adverse effect of causing thrombocytopenia (low blood platelet count) in 1 per 2.9 million cases. Canada has an annual birth cohort of approximately 400,000 babies. This means that it would take over seven years for a true vaccine-associated occurrence of thrombocytopenia to appear, amidst a background of cases of thrombocytopenia resulting from some other factor.
How is it possible for researchers to pinpoint this single case as being caused by the vaccine? Worse than looking for a needle it a haystack, it would be comparable to searching for a single specific needle in a stack of needles. “People who stand up and shout [that] we have the tools to determine what vaccines are safe or not before we give them to people, that’s complete nonsense. We don’t. We’re pretty good but nowhere near that good for looking at these incredibly rare events,” added Ward, “but that’s the expectation of the population… We just don’t have the tools.” Although technology is advancing, and adverse event reporting programs are improving, we are far from a CSI: Crime Scene Investigation level of scientific field-work.
The Public Health Agency of Canada [PHAC] childhood National Immunization Coverage Survey of 2013 asked Canadian parents about knowledge, attitudes and beliefs related to vaccines and vaccination. The survey revealed that 95 per cent of parents agreed that childhood vaccines are safe. Similarly, 97 per cent of parents thought that vaccines are effective and important for children’s health. However, nearly 70 per cent of parents expressed some degree of concern on the possible side effects of vaccines. More than one third falsely believed that a vaccine could cause the disease it was intended to prevent. Almost five percent of parents strongly believed that alternative practices, such as homeopathy or chiropractic, could eliminate the need for vaccines.
Homeopathic alternatives, such as nosodes, are not a substitute for vaccines. There are no suitable substitutes for vaccines. A CBC Marketplace investigation found that alternative health practitioners offer unproven vaccine “alternatives,” adding to many parents’ confusion regarding vaccines. Nosodes are prepared as dilutions of diseased tissue or excretions secreted during the course of a disease below concentrations expected to have protective effects, to a point where any trace of the original substance is likely not present. Homeopathic practitioners claim that the “memory” of the original substance is sufficient to create immunity. While no regulations prohibit homeopathic practitioners from offering health advice or alternative remedies, and to prove their positive effects, these treatments are not approved by Health Canada as an alternative to immunization. Medical experts agree that there is no scientific proof to substantiate their efficacy.
These results demonstrate a need for improved public education on immunization. If the willingness to vaccinate is placed on a spectrum, there are committed percentages at both ends, those whom are resolutely behind vaccines, and those against. However, from the PHAC data above, approximately 70 per cent of parents waver somewhere in the middle of this spectrum. These vaccine-hesitant parents are the target of most physician and researcher efforts to communicate with, better understand, and come to some sort of compromise with.
When the burden on the public and scientific community to communicate was discussed, Ward said, “Of course it’s always on the shoulders of the scientists to communicate and make sure the people understand, and do so in a way that’s easy for people to understand. It’s also incumbent on the scientists and [physicians] to be completely transparent about risks. You have to acknowledge right up front that there is no such thing as a safe vaccine.” The discussion often boils down to one of understanding and accepting risk. “You have to be sensitive to each individual’s concept of risk […] to say to somebody who’s worried ‘there’s no risk.’ It is much more effective to say ‘the risk is really small and I vaccinate my children.’ ” By moving the complex discussion of factors involved in vaccine safety to a simple understanding of the associated risks, as well as personal reassurance, “it’s completely transparent and it also says I know a whole lot more than you about the relative risks and I chose to accept those risks for my children,” said Ward, “So either I’m a shitty parent, or I’ve made an informed decision.” Heidi Larson, an anthropologist at the London School and Hygiene and Tropical Medicine echoed this sentiment during an interview with BBC News, “the reason that people get more entrenched in their opposition to vaccination is they feel like they’re not being listened to. So you don’t throw information at the problem. Instead you learn to listen.”
Vaccine-hesitant parents are the target of most physician and researcher efforts to communicate with, better understand, and come to some sort of compromise with
“As a profession, our first step has to be to look at ourselves [and] say what are we doing wrong,” noted Ward. An important solution to dispelling misinformation around vaccines could therefore be that physicians and researchers devote more time to addressing doubts in a closed setting with hesitant parents.
In order for this method to be productive, parents must have the will and capacity to put risks into perspective. For most, honesty is the best policy, and transparency is imperative to trusting. Like any medicine, vaccines may carry real risks, ranging from minor swelling and fever, to rare but serious adverse effects including seizures and anaphylaxis. Doctors can begin to build trust by framing these risks alongside the dangers of disease, or comparing them to risks assumed in daily life. For example, a serious encephalomyelitis (inflammation of the brain and spinal cord) due to administration of the MMR vaccine occurs once in 1 million doses. In comparison, an individual is more likely to die in a car accident (one in 113), to suffer a severe anaphylactic allergy to penicillin (one to five in 10,000), or to be struck by lightning (1 in 13,000). These comparisons can be useful to truly appreciate the safety of current vaccines.
In addition to directly interacting with the public, it is integral for physicians and researchers to acquire an “expert versus expert” mindset to dispel propagation of false information by members of the medical and scientific communities. “The one’s I single out for the most pointed criticism is my peers. The medical and scientific experts. There has got to be consequences for people who stand up and spout nonsense,” insisted Ward, “I think we’ve been too passive.” The onus is on members of these respective communities to call out and challenge fraudulent claims made by their peers.
“We ask citizens to get vaccines to prevent 14 different diseases, which can mean as many as 26 inoculations in the first few years of life, to prevent diseases that people mostly don’t see, using biological fluids that most people don’t understand,” said Paul Offit, the head of an infectious-diseases division at the Children’s Hospital of Philadelphia during a Q&A with University of Pennsylvania newspaper the Penn Current, “it’s not surprising that people are hesitant.” People can reject vaccines for a variety of reasons, such as personal or religious reasons, scare stories incubated on the internet and amplified by headline-driven media outlets, or due to fading memories of vaccine-preventable diseases that programmes have so adequately eliminated that we gladly forget their symptoms and risks.
Parents are responsible for the well-being of their children, including protection from diseases that are easily preventable. But with the population of vaccine-hesitant parents continuing to expand, we can only expect the committed anti-vaccination movement to grow as well. However, this is a different issue from smoking, or removing a seatbelt, where one knowingly accepts the risks associated as an individual. The choice made by parents not to vaccinate their child puts the livelihood of innocent children at risk.
“When I am confronted by somebody like that [parents who refuse to vaccinate children] I say I really hope for the sake of your children that your decision, which I think is ill-informed, [does not result] in them dying from tetanus or being hurt by measles. That, to me, would be a horrible outcome for both of us,” said Ward. Unfortunately, trends in the public perception of science, the government, and the vaccine industry highly contributes to parents’ distrust of vaccines. The public must learn to support credible scientific research and facts, to avoid misguidance and make well-informed decisions.