The study tests the effects of vaccination messages in television news

Covering the news with expert scientific evidence on vaccine safety effectively increases the increase in vaccine acceptance by the public, but the positive effect diminishes when the expert message is compared to a personal narrative of actual side effects, new research has shown.

The study, conducted by researchers linked to the Annenberg Center for Public Policy (APPC) at the University of Pennsylvania and the University of Illinois, tested the effects of vaccination messages on television news.

They included videos of Dr. Anthony Fauci, director of the American National Institute of Allergy and Infectious Diseases, who talks about evidence supporting the value and safety of the MMR vaccine (measles, mumps and rubella) and the mother who refuses to vaccinate her. the youngest child because her middle child, who has a rash, had what she characterized as severe reactions after receiving the MMR vaccine.

Research published in PLOS ONE, it is based on an experiment with a nationally representative sample of 2,345 participants during the 2019 measles outbreak in the United States.

The study “Effects of Scientific Messages and Narratives on Vaccination” found that:

  • Fauci’s message “supporting science” had significant positive effects on attitudes about vaccination compared to the control message. Participants exposed to the expert message had a lower perception of vaccination risk; stronger attitudes about pro-vaccine policy; and stronger intentions to send a vaccine letter to the state representative and encourage other people to vaccinate their children.
  • The mother’s narrative of “hesitation” had no significant effect on these outcomes.
  • But when the two messages collided, with a video of the mother preceding Fauci, the mother’s hesitation narrative diminished the effectiveness of the vaccine message, according to some measures.

“In this paper,” the authors write, “we have treated parental reports of potentially real side effects as hesitant narratives because, even when accurate, their portrayal in the media can lead to over-generalization and hesitation of the vaccine in fuel leading the public to draws inaccurate conclusions about the prevalence and severity of side effects.

In short, individual cases of vaccine side effects, even if true, can lead to false conclusions, and the media’s reliance on dramatic and vivid cases can lead to overestimating risks that are relatively rare. “


The experiment was conducted from February 28 to March 18, 2019, during the largest American measles epidemic in more than a quarter of a century. “We’ve often wondered about vaccine side effects stories – like the concerns we recently heard with 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 these stories have negative effects on vaccine support and how do we ensure that people understand science accurately?”

Previous research has failed to simulate real news by assessing the effects of exposure to both messages from experts about the value of vaccination and personal reports of reasons for hesitation about vaccination discussing real but relatively rare side effects.

According to the Centers for Disease Control and Prevention (CDC), “pain, redness or rash at the injection site and rash all over the body can occur after an MMR vaccine,” while “more serious reactions are rare,” including seizures, temporary pain, and stiffness. joints, pneumonia and swelling of the brain and / or spinal cord cover. “As with any other drug, there is very little chance that the vaccine will cause a serious allergic reaction, another serious injury or death.”

The researchers said: “This dual aspect of vaccine side effects – their rare existence and people’s tendency to generalize from individual stories – puts their portrayal in the media in what we consider a gray area between accurate and misleading information. Therefore, we set the media coverage of such stories without adequate contextualisations can be misleading and potentially affect public opinion. “

Vaccine videos

In this experiment, the researchers used edited videos from television news with network identification removed. 2,345 participants were randomly assigned to watch one of six short, edited videos:

  • (1) the mother’s account of “hesitation”;
  • (2) Fauci’s expert, a statistically significant video that “supports science”;
  • (3) a video of “science-supporting parents” of parents whose children would be at risk if exposed to measles but were unable to receive the vaccine for other health reasons or who became infected with measles and experienced complications;
  • a combination of the narrative of the mother (1) and Faucius (2);
  • a combination of the stories of the mother (1) and other parents (3);
  • control video on the benefits of aspirin.

After watching the video, participants answered questions about the risk of the vaccine, support for vaccination policies, their intentions to encourage parents to vaccinate their children, and whether they would agree to send a vaccination letter to a state representative.

About the findings

Contrary to the researchers’ initial hypothesis, the mother’s “hesitant” narrative did not in itself affect outcomes – which, the authors say, was “largely consistent with research suggesting that exposure to individual messages rarely had an impact.” However, the fact that it has diminished the positive effects of Fauci’s video raises concerns and calls for further studies.

It may be that when we hear a mother’s narrative in isolation, we don’t make a big deal out of it. But when people subsequently hear about science, it encourages them to think about vaccines, mothers remember, and it haunts them with doubts. “

Dolores Albarracín, Co-author and Professor of Studies, Psychology and Business Administration, University of Illinois, Urbana-Champaign

Albarracín is also a prominent researcher at APPC.

Kathleen Hall Jamieson, co-author and director of the Annenberg Policy Center, noted that Fauci delivers an unconditional “sure” message about the MMR vaccine. “Nothing the mother says is incorrect,” Jamieson said. “We hypothesize that exposure to her story and visualized evidence of her older child full of rash call into question Dr. Fauci’s categorical claims about vaccine safety.”

The video from a parent who supports science was found to be relatively ineffective with respect to Fauci’s message.

Implications for COVID-19 messaging

The researchers said the findings have important implications for public health messaging and editorial decisions about COVID-19 vaccine coverage.

“We do not recommend that the media stop reporting on vaccine safety and side effects,” Albarracín said. “But our recommendation is that statistical information on vaccine trials should be communicated to the public multiple times and early, before vivid narratives about side effects are captured.”

Jamieson added, “The scientific community needs to remind the public that the benefits of using approved vaccines outweigh the risks – and that the risks associated with contracting the disease far outweigh any associated with the vaccine.”


Annenberg Center for Public Policy from the University of Pennsylvania

Journal reference:

Kuru, O., and others. (2021) The effects of scientific messages and narratives about vaccination. PLOS ONE.