Effective Vaccine Communication during the Disneyland Measles Outbreak

"Both social media and provider recommendations can influence parental decision-making about vaccination, and our findings suggest practical implications and future research questions for public health communicators and clinicians."

This research report explores communication around a measles outbreak that brought national attention in the United States (US) to fear of vaccination, which has increased the rate of vaccine refusal in recent years. The outbreak, which started in late 2014 at Disneyland (an amusement park in California, the US), led to 111 cases in 7 US states, as well as Canada and Mexico. The researchers observe that American Academy of Pediatrics recommendations do not specify the most effective manner for physicians to communicate the latest evidence-based statistics - the "risks and benefits" - associated with vaccines and their refusal. Furthermore, research shows that communicating statistical information on its own may be ineffective or even counterproductive and that a story may be more effective than communicating statistical data. More than 30% of the general US population report getting news from Facebook, and some groups receive a majority of their news from social media; these articles inform decisions about a range of issues, prompting health behaviour change.

In that context, this retrospective observational study was designed to test Fuzzy-Trace Theory (FTT)'s prediction that vaccine-relevant articles expressing "a gist" are more likely to be shared on Facebook when compared to articles expressing verbatim statistics. As the researchers explain, FTT is a theory of medical decision-making that explains the process by which individuals derive meaning from information they are given. Specifically, FTT emphasises differences in the way people process precise details such as statistics ("verbatim"), versus simple bottom-line meaning ("gist"). Gists emphasise categorical contrasts between decision options (e.g., "If you do not vaccinate your child, there is a real chance that they could get sick"). Gist is expected to be more compelling than verbatim.

The researchers coded 4,581 news articles with 4,000 words or fewer containing vaccine-related keywords published during the Disneyland measles outbreak - November 18 2014 through March 26 2015 - after having using news search application protocol interfaces (APIs). They used the public Facebook API to measure the number of times these articles were shared, each article's length, whether or not an image was present, and each article's readability (per the Flesch-Kincaid Index). After applying a logarithmic transform to the Facebook shares data to correct for positive skew, they conducted a linear regression on those articles that were shared at least once. They applied the same regression techniques to articles containing gists to determine if article sentiment (positive, negative, or none) was associated with more sharing on Facebook.

After controlling for article length, readability, and presence of images, they found that statistics and gists were significant predictors of whether an article was likely to be shared at least once (see Table 1). Furthermore, linear regression showed that articles with gists were shared 2.4 times more often, on average, than articles without gists. Among articles with gists that were shared at least once, linear regression showed that those expressing positive opinions about both those who endorse and those who oppose vaccination were shared 57.8 times more often, on average, than articles with other sentiments. Stories did not significantly increase Facebook shares, suggesting that stories may only be effective to the extent that they serve to communicate a clear gist. Furthermore, consistent with decades of prior research cited here, the most popular articles acknowledged both sides of the argument, indicating that although the the same information was shared, meanings emphasised may have differed.

The researchers suggest that these results can inform the content of public health communications that aim to use social media for outreach. "Public health officials seeking to increase vaccine uptake must recognize that verbatim statistical facts alone may not be persuasive. Indeed, although people generally encode both verbatim and gist representations of familiar information, clarifying and emphasizing the gist of unfamiliar information can facilitate its comprehension." They continue by stating that: "Communication strategies that resonate on social media may also succeed in interactions between health care providers and patients. Although not a cure-all for vaccine refusal, more effective, targeted communication from providers can have a desirable impact on these decisions. Our findings suggest the need for further research into possible applications for explicit inclusion of gist in both patient-provider interactions and in communication materials directed at patients."

To facilitate further dialogue about and work in this arena, the researchers propose a "gist communication framework" (see image above) which they suggest could form the basis of communication training for healthcare providers in how to include gist along with statistics. This proposed framework uses a series of short scripts healthcare providers can employ across health topics and conversations and need not require lengthy conversation. The technique could be used both during in-person provider-patient interactions and in the preparation of print and digital messages designed to reach patients. For example, a paediatrician addressing a vaccine-hesitant parent about measles might use an evidence-based verbatim statement: "Vaccines, like any medicine, can have side effects, but most children who get the measles, mumps, and rubella (MMR) shot have no side effects; however, measles can lead to pneumonia, deafness, lifelong brain damage, or even death, and almost one-third of children with measles have to be hospitalized." (The researchers state that acknowledging the occasional occurrence of adverse vaccine events may increase credibility.) The physician then could follow that with a scripted phrase, such as: "So what I tell my patients is..." and conclude with a categorical gist: "Taking any risk that your child could get the measles and suffer serious complications just isn't worth it. Vaccination is the best way to protect your child."

In conclusion: "FTT is an effective framework for understanding medical decision-making. Our results suggest it can help explain the persuasiveness of social media messages related to vaccination."