Misinformation and selective coverage change perception of outbreaks, but can be corrected by presenting the facts

While it’s not an animal product, the Listeriosis outbreak recently traced to apples is just as relevant to the food industry as a whole as any other food-borne illness outbreak. While I was looking for more information on the outbreak, I came across this gem* of an article posted on cnn.com.

*When this post was originally written, the text on the website read: “At least seven people have died after eating caramel apples that may have been infected with Listeria monocytogenes. Followed immediately by a quote from CDC which stated ‘Thirty-one ill people have been hospitalized and six deaths have been reported. Listeriosis contributed to three of these deaths, and it is unclear whether it contributed to an additional two deaths. The sixth death was unrelated to listeriosis.'” CNN has since removed the CDC quote, but kept their original ‘7 deaths’ statement.”

I found this disturbing on two levels. First, the fact that they reported that at least six people had died after eating contaminated apples, when listeriosis was only confirmed as cause of death for 3 of the cases and ruled out for the 6th.

“Hey Jen, what’s the body count up to on that outbreak article?”

“Looks like 3 for sure, could be 3-5”

“Thats it?”

“Don’t worry, we’ll round up to 6+, if you use a Log scale, they’re practically the same number.”

Second, they used the direct quote from CDC’s 12/31 update to directly contradict themselves in the following sentence. Who wrote this article? (update, clearly they wizened up and removed the quote on Jan 15, I wonder if they saw the reddit post. This is also a rhetorical question, their name is on the article, but we also need to assign blame to their editor.).

So what sort of impact could this statement have? Young, Norman, and Humphries reviewed the impact of media coverage on how dangerous we think they are. They found that indeed, those conditions/diseases that receive more media coverage are perceived by medical students as a “worse” condition. This can actually be a very good thing for infectious disease outbreaks, as rapid media coverage of the danger encourages people to avoid contact with others, leading to exponentially fewer cases the earlier you do it. This is less good however, when non-infectious diseases or inaccurate correlations are blown out of proportion (e.g. people avoiding pork to avoid H1N1).

The literature review included in the beginning of the article shows that this isn’t necessarily new information. However, the authors also examined the effect or including additional “objective” information about the conditions when asking students to rank their risk. The result was that, as seen in the chart below, when provided additional information the study participants then changed their views of the diseases. The large separation between what they had seen in media and what they had not seen shrank and they assigned more risk to those threats that aren’t often talked about, and became less nervous of the high coverage items in comparison.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0003552As a science blogger, this is my soapbox, as this study highlighted the responsibility for those who know more than the headline to speak up and share their knowledge, because people can and will be receptive to it as long as it’s available.

Unfortunately, the study was inherently biased as medical students are more likely to be receptive to new data (especially related to disease) as opposed to other groups with stronger existing bias’ (e.g. CAM users, anti-vaccination proponents, specialist doctors, or epidemiologists who may be swayed by previous outbreak coverage). The authors specifically did not survey students on their current media usage or biases, and therefore could not demonstrate the power of providing additional information on subjects they may have already formed strong opinions on.

I’d like to see the study repeated with an older group, as student’s opinions are more likely to be malleable as they are less likely to know as much about these illnesses or had personal experiences with them. A repeated study with participants of at least 40-years-old would be more telling and help us understand what effect providing additional objective information can have.

After all, as nice as it is to know students can be taught, they’re not the ones in public office. Are they also willing to change their minds when new information is made available?
Young ME, Norman GR, & Humphreys KR (2008). Medicine in the popular press: the influence of the media on perceptions of disease. PloS one, 3 (10) PMID: 18958167

Mummert A, & Weiss H (2013). Get the news out loudly and quickly: the influence of the media on limiting emerging infectious disease outbreaks. PloS one, 8 (8) PMID: 23990974ResearchBlogging.org

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