Vaccine science and side effects: How news messages affect views on vaccination
News coverage of expert scientific evidence on vaccine safety is effective at increasing public acceptance of vaccines, but the positive effect is diminished when the expert message is juxtaposed with a personal narrative about real side effects, new research has found.
The study, by researchers affiliated with the Annenberg Public Policy Center (APPC) of the University of Pennsylvania and the University of Illinois, tested the effects of messages about vaccination in televised news reports. These included video clips of Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, talking about evidence supporting the value and safety of the MMR (measles, mumps and rubella) vaccine, and a mother who's refusing to vaccinate her youngest child because her middle child, who is shown with a rash, had what she characterized as severe reactions after receiving the MMR vaccine.
The research, published in PLOS ONE, is based on an experiment with a nationally representative sample of 2,345 participants during the 2019 U.S. measles outbreak.
The study, "The Effects of Scientific Messages and Narratives About Vaccination," found that:
Fauci's "science-supporting" message had significant positive effects on views about vaccination when compared with a control message. Participants exposed to the expert message had lower perceptions of risk from vaccination; stronger pro-vaccine policy views; and stronger intentions to send a pro-vaccine letter to a state representative and to encourage other people to vaccinate their children.
The "hesitancy-inducing" narrative by the mother had no significant effect by itself on these outcomes.
But when the two messages were juxtaposed, with video of the mother preceding Fauci, the mother's hesitancy narrative diminished the effectiveness of the pro-vaccine message, according to some measures.
"In this paper," the authors write, "we treated parental reports of potentially real side effects as Hesitancy-Inducing Narratives because, even when accurate, their portrayal in media can lead to overgeneralization and fuel vaccine hesitancy by leading the public to draw inaccurate inferences about the prevalence and severity of side effects. In short, individual cases of vaccine side effects, even if true, may elicit false inferences, and the media's reliance on dramatic and vivid cases may lead to overestimation of risks that are relatively rare."
The research
The experiment was conducted from February 28-March 18, 2019, during the largest U.S. measles outbreak in over a quarter-century. "We often wondered about stories of vaccine side effects - like the concerns we've heard recently with the COVID-19 vaccines," said lead author Ozan Kuru, who worked on the study as a postdoctoral fellow at APPC and is now an assistant professor in the Department of Communications and New Media at the National University of Singapore. "Do those stories have negative effects on support for vaccines, and how do we ensure that people have an accurate understanding of the science?"
Prior research has failed to simulate the actual news environment by assessing the effects of exposure both to experts' messages about the value of vaccination and to personal accounts of the reasons for vaccination hesitance that discuss actual but relatively rare side effects.
The study, by researchers affiliated with the Annenberg Public Policy Center (APPC) of the University of Pennsylvania and the University of Illinois, tested the effects of messages about vaccination in televised news reports. These included video clips of Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, talking about evidence supporting the value and safety of the MMR (measles, mumps and rubella) vaccine, and a mother who's refusing to vaccinate her youngest child because her middle child, who is shown with a rash, had what she characterized as severe reactions after receiving the MMR vaccine.
The research, published in PLOS ONE, is based on an experiment with a nationally representative sample of 2,345 participants during the 2019 U.S. measles outbreak.
The study, "The Effects of Scientific Messages and Narratives About Vaccination," found that:
Fauci's "science-supporting" message had significant positive effects on views about vaccination when compared with a control message. Participants exposed to the expert message had lower perceptions of risk from vaccination; stronger pro-vaccine policy views; and stronger intentions to send a pro-vaccine letter to a state representative and to encourage other people to vaccinate their children.
The "hesitancy-inducing" narrative by the mother had no significant effect by itself on these outcomes.
But when the two messages were juxtaposed, with video of the mother preceding Fauci, the mother's hesitancy narrative diminished the effectiveness of the pro-vaccine message, according to some measures.
"In this paper," the authors write, "we treated parental reports of potentially real side effects as Hesitancy-Inducing Narratives because, even when accurate, their portrayal in media can lead to overgeneralization and fuel vaccine hesitancy by leading the public to draw inaccurate inferences about the prevalence and severity of side effects. In short, individual cases of vaccine side effects, even if true, may elicit false inferences, and the media's reliance on dramatic and vivid cases may lead to overestimation of risks that are relatively rare."
The research
The experiment was conducted from February 28-March 18, 2019, during the largest U.S. measles outbreak in over a quarter-century. "We often wondered about stories of vaccine side effects - like the concerns we've heard recently with the COVID-19 vaccines," said lead author Ozan Kuru, who worked on the study as a postdoctoral fellow at APPC and is now an assistant professor in the Department of Communications and New Media at the National University of Singapore. "Do those stories have negative effects on support for vaccines, and how do we ensure that people have an accurate understanding of the science?"
Prior research has failed to simulate the actual news environment by assessing the effects of exposure both to experts' messages about the value of vaccination and to personal accounts of the reasons for vaccination hesitance that discuss actual but relatively rare side effects.