Fact boxes: A tool to immunize the public against vaccine misinformation

The following guest post is co-authored by Mirjam Jenny, Head Research Scientist at the Harding Center for Risk Literacy, and Ina Baum, a Research Coordinator at the Center. The Harding Center is an initiative of the Max Planck Institute for Human Development in Berlin, which is directed by one of the leading figures in risk communication, Gerd Gigerenzer. The Center’s goal is to help people understand and assess risks, especially in the realm of health and medicine, and to use that increased understanding to make better decisions. 


Outbreaks of measles have received increased media attention in the past few years: a toddler died from the disease in Berlin in 2015, the Glastonbury Festival in the UK saw a high rate of reported cases in 2016, and one sick visitor passed the highly contagious illness on to more than 150 others at Disneyland in California, to name just a few. These reports coincide with fluctuating vaccination rates and conflicting information about the harms and benefits of the vaccine.

Let’s start with the basics: How vaccines work

Vaccines imitate an infection and thereby stimulate immunization against invading bacteria or viruses. Each vaccine is specifically tailored toward how the virus or bacteria function; for example, some contain a weakened version of the actual virus, while others make use of inactivated viruses. In each case, though, the immune system responds to the germs by ramping up production of several white blood cells (primarily antibodies produced by B-lymphocytes, macrophages, and T-lymphocytes) that attack the germs.

Mirjam Jenny

Mirjam Jenny

Once the imitation infection subsides, the body retains memory T-lymphocytes, which jump into action quickly should the same germ be detected again. With between about 80-95% of the population vaccinated (depending on the disease), so-called herd immunity protects those who cannot be vaccinated (e.g. groups with a severely weakened immune system like newborns or cancer patients), because the disease is much less likely to spread.

 

‘Herd immunity’ is being compromised. Here’s why.

In 2000, measles were declared eradicated in the US. However, since then, the Centers for Disease Control and Prevention (CDC) has reported a number of serious outbreaks, with a high of 668 cases in 2014. Why is this happening?

Many experts point to a growing number of parents failing to fully vaccinate their children or delaying their vaccinations. Part of this anti-vaccination movement can be traced back to a single article published in 1998, claiming a link between the Measles Mumps Rubella (MMR) vaccine and autism. This claim has been well refuted by a large body of scientific research and the article was retracted by the journal. However, the notion that MMR vaccines are not safe has permeated the public mind. Even in the most recent US presidential election, candidates referred to a link between being vaccinated and development of autism.

On the other side of the globe, the Australian government recently made the drastic decision to withhold childcare and welfare benefits if parents miss children’s routine vaccinations to address declining vaccination rates. Facing similar realities, the European Center for Disease Prevention and Control published a technical paper meant to “dispel the myths about measles vaccination.”

Ina Baum

Ina Baum

The stark contrast between public perception and scientific reality has motivated much research into media coverage of the MMR issue and declining national vaccination rates in the US and the UK. Results have shown that the press coverage provided a false balance – reports indicated that there were competing claims, but did not provide a “sense of the weight of scientific evidence.” Readers and viewers were left with a feeling of equally valid positions for and against vaccination.

Coverage also focused excessively on isolated incidents and personal stories, in the UK most prominently on the question of whether then-Prime Minister Tony Blair’s youngest son Leo would receive an MMR vaccination. While the constant repetition of the (scientifically false) suggestion of a link between autism and MMR received much media coverage, a clear, easily-accessible and understandable statement of scientific evidence was lacking.

Fact boxes are an antidote to confusing, low-quality information

Unfortunately, both doctors and patients are often confronted with medical information that either is low in quality, is conveyed in a confusing format, or both. Simple, understandable, and accurate medical information is rare, and information that conveys medical evidence with accessible statistics is even rarer. How can we help patients make informed decisions?

Simple fact boxes that we have developed here at the Harding Center for Risk Literacy — based on an idea first proposed by Steve Woloshin and Lisa Schwartz at Dartmouth University — are a promising solution. All numbers contained in a fact box are delivered in absolute terms, which makes it easier (compared with relative risk figures) for readers to conceptualize the true size of the benefit (or harm) conferred by the intervention. Fact boxes such as the MMR fact box below (click the image for a larger version) are based on the best available medical evidence, ideally on multiple randomized controlled trials, reviews, or meta-analyses, which are referenced. Fact boxes always clearly state to what group of people the numbers refer, while a simple summary highlights the most important facts.

Let’s look at the benefits in the measles example first. According to model estimation, out of 10.000 people who weren’t vaccinated, 9.310 will contract measles if they are exposed to the measles virus. Under the same conditions, only 93-745 of 10.000 vaccinated people will contract measles. In the vaccinated group, fewer patients will get fever, pneumonia, or encephalitis (brain swelling) and fewer die.

Now let’s look at the harms. Zero to one child out of 10.000 vaccinated children suffers from thrombocytopenia (low platelet count which, in rare cases, could cause internal bleeding) and about 2-16 suffer from febrile convulsion (seizures associated with fever). Based on this information, patients can decide whether the benefits of a vaccination outweigh the harms.

Exploring the practical applications of fact boxes

The fact box on measles vaccination can help doctors communicate the most relevant medical evidence to their patients and patients can also study the material themselves. Fact boxes are useful not only for vaccinations but a myriad of other topics such as cancer screening, drugs, and other medical treatments.

The Harding Center for Risk Literacy in Berlin is currently collaborating with health insurers and doctors’ organizations to develop and distribute fact boxes. In Germany, the AOK, one of the largest German health insurance companies, is a main driving force in this endeavor. In Switzerland, Helsana, one of the biggest Swiss insurers, recently published several fact boxes on vaccinations. Next to links to the fact boxes published on the Harding Center website, Helsana provides patients with written information as well as with informative videos, which are all available in English:

In the future we hope to promote patient empowerment internationally with fact boxes and other evidence-based tools of risk communication, always fostering independent, informed decision-making.

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Comments (2)

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Peter Sandman

December 9, 2016 at 12:54 pm

I have no quarrel with “fact boxes” – or any other communication technique that helps people understand risks and benefits. But I do have a fundamental quarrel with the measles fact box featured in this article: It says nothing about the incidence of measles.

Instead, the fact box assumes that a vaccinee will be exposed to measles. Based on that assumption, it compares the efficacy of the MMR combo vaccination in preventing measles infection with the possible side-effects of the shot.

Parallel facts and exactly the same logic could be used to show that parents should also give their children yellow fever vaccinations and even smallpox vaccinations. In those cases too, the vaccine is less dangerous than going unvaccinated … for a person who is exposed to the pathogen. But since most Americans (and most Germans) are highly unlikely to encounter yellow fever or smallpox, neither vaccine is routinely administered.

The authors say the goal of the fact box is to help readers “conceptualize the true size of the benefit (or harm) conferred by the intervention.” But assessing an intervention without considering the likelihood of the outcome the intervention aims to prevent is a very basic sort of misleading risk communication – one I wouldn’t have expected to see from Health News Review or the Harding Center.

The “true size of the benefit” of the measles vaccine cannot be assessed based on a fact set that assumes exposure.

In fact, the vast majority of people in the U.S. are never exposed to measles. I don’t want to be misunderstood here. In the long term, herd immunity against measles and other childhood infectious diseases prevents huge amounts of mortality and morbidity. If sizable numbers of U.S. parents stopped vaccinating their children, these diseases might very well come roaring back. But in the U.S. so far, the number of parents who don’t vaccinate their children falls pretty far short of the number that would yield this disastrous outcome.

The authors mistakenly claim that measles was declared “eradicated” in the U.S. in 2000. They add: “However, since then, the Centers for Disease Control and Prevention (CDC) has reported a number of serious outbreaks.” But the 2000 declaration concerned the “elimination” of measles, not its eradication – a term of art the CDC defines as “interruption of year-round endemic transmission.” Despite periodic outbreaks, measles is still eliminated in the U.S. today.

Imagine that you’re a pediatrician in a typical U.S. community, not one of the pockets where large numbers of people are unvaccinated and herd immunity is genuinely inadequate. The parents of a patient wish to skip their child’s MMR. (Leave aside legal requirements for the sake of this hypothetical.) The probability that vaccinating the child will lead to a serious adverse reaction, something like anaphylaxis, is of course tiny. The probability that not vaccinating the child will lead to a case of measles with serious long-term morbidity is also tiny. I don’t know which risk is bigger, but surely we can agree that both are negligible, both on the order of one-in-a-million or less.

In other words, parents who don’t vaccinate their children against measles are free-riders. They are not doing their share to sustain herd immunity. But at least so far, herd immunity in most neighborhoods is being satisfactorily sustained without them. In the absence of a current outbreak, if you tell your patient’s parents that they are seriously endangering their child or a neighbor child by skipping or postponing the MMR, you are either misinformed or dishonest.

The authors’ “fact box” notwithstanding, the current risk of serious health harm to a U.S. child who is given the MMR is roughly equivalent to the current risk of serious health harm to a U.S. child who is not given the MMR. The former risk consists of rare significant side effects from the vaccination; the latter risk consists of the rare possibility that the child will be exposed to measles, catch it, and suffer significant health consequences.

You can make a good case for requiring everyone to get the MMR, precisely because it’s a “prisoner’s dilemma” situation: It is fairly sensible for the individual child not to get the MMR as long as most other nearby children do get the shot, but everyone is better off if everyone is required to get it than if lots of children fail to get it. So requiring the MMR makes sense. But telling a parent that not vaccinating his or her child is taking an unconscionable risk is simply false.

It’s a fair question whether this sort of dishonesty is justified in the interests of encouraging a highly desirable outcome, such as MMR vaccination. I have long argued that even altruistic dishonesty risks undermining the credibility of vaccination in particular and public health in general. But I don’t have much evidence that it has done so. (See http://www.psandman.com/col/dishonesty.htm — “U.S. Public Health Professionals Routinely Mislead the Public about Infectious Diseases: True or False? Dishonest or Self-Deceptive? Harmful or Benign?”) Perhaps this is a question Health News Review and the Harding Center will want to investigate.

    Mirjam Jenny

    January 3, 2017 at 7:52 am

    Dear Dr. Sandman,

    Thank you for your insightful response. We would like to respond to a few of your comments.

    As we mention in the text, the fact box can help communicate the most relevant information and can help patients to better understand the benefits and harms of a treatment. The fact box serves as complementary information about medical interventions and can thereby contribute to informed decision making. However, a fact box cannot replace a comprehensive evidence-based health information or decision aid.

    On the Harding Center website, every fact box is embedded in additional information, which includes explanations on, for example, how to read the fact box, the quality of evidence, and the medical intervention discussed. For the purpose of this HealthNewsReview.org contribution, we opted for a shorter version owing to space limitations.

    As you point out, the incidence of measles is needed to clearly communicate the information provided in the fact box. To be sure, the nature of the studies forming the basis of the fact box is transparently explained on the Harding Center website, and we have also included this in the text for HealthNewsReview.org. We are currently considering elaborating on incidence and exposure in the accompanying information, as you suggest. This requires careful consideration of annual and geographical fluctuation.

    Thank you for the correction in terminology. Yes, measles have been eliminated on US soil, while the global eradication remains a desirable goal. In the text, we do not suggest that measles are no longer eliminated in the US, but should have stated this clearly.

    We would also like to thank Felix G. Rebitschek, Jana Hinneburg and Christin Ellermann for their work on the fact box and for contributing their expertise to this response.

    Dr. Mirjam Jenny
    Head Research Scientist
    Harding Center for Risk Literacy