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.
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.
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.
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.”
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.
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.
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.