Dartmouth/Univ. of Exeter Study: Correcting myths about the flu vaccine

HANOVER, N.H. - December 8, 2014 - With health systems in the U.S., U.K., and around the world trying to increase vaccination levels, it is critical to understand how to address vaccine hesitancy and counter myths about vaccine safety. A new article in the journal "Vaccine" concludes, however, that correcting myths about vaccines may not be the most effective approach to promoting immunization among vaccine skeptics. The study, which was co-authored by Brendan Nyhan, an assistant professor of government at Dartmouth College, and Jason Reifler, a senior lecturer of politics at the University of Exeter, found that debunking the myth that the seasonal influenza vaccine can give you the flu actually reduced intent to vaccinate among people who are most concerned about vaccine side effects. (The journal article will be available on December 8 on Vaccine's site via doi:10.1016/j.vaccine.2014.11.017).

The study was conducted with a nationally representative sample of adults in the U.S. collected as part of the 2012 Cooperative Congressional Election Survey. Respondents were randomly assigned to one of three conditions: a control condition in which no additional information about the flu or flu vaccines; a danger condition that presented information about the health risks posed by the flu; and a correction condition that informed respondents that they cannot contract the flu from the flu shot or live virus nasal spray. Both interventions were adapted nearly verbatim from Centers for Disease Control and Prevention materials. The researchers then compared the beliefs and intended behaviors of respondents after exposure to these messages.

The following is an overview of the study's results:

• More than four in ten Americans (43%) endorsed the myth that the flu vaccine can give you the flu, saying it is either "somewhat" or "very accurate."

• Respondents who received corrective information that the flu vaccine cannot give you the flu were less likely to report believing in this misperception or to say that the flu vaccine is unsafe.

• However, providing this corrective information also reduced the self-reported likelihood of getting a flu vaccine among respondents with high levels of concern about vaccine side effects. This information had no significant effect on intention to vaccinate among respondents with low concern about side effects.

• Providing information about the dangers of the flu had no effect on respondent beliefs about vaccine safety or their self-reported intention to vaccinate.

"Our findings suggest that corrective information can successfully reduce false beliefs about vaccines. However, that corrective information may unfortunately cause people with fears about side effects to bring those other concerns to mind and thereby reduce their intention to vaccinate," said Nyhan. "We need to learn how to most effectively promote immunization. Directly correcting vaccine myths may not be the most effective approach."

The study's results are consistent with other findings by Nyhan and Reifler, which indicate that corrections of misperceptions about controversial issues may have unexpected or counterproductive results, including a previous study of the effects of correcting misperceptions about the measles, mumps, and rubella (MMR) vaccine. Previous study links:

• http://link.springer.com/article/10.1007%2Fs11109-010-9112-2
• http://pediatrics.aappublications.org/content/early/2014/02/25/peds.2013-2365

###

The published paper “Does correcting myths about the flu vaccine work? An experimental evaluation of the effects of corrective information” by Brendan Nyhan and Jason Reifler will appear in Vaccine, which is published by Elsevier.

Copies of the paper are available to credentialed journalists upon request; please contact Amy Olson at amy.d.olson@dartmouth.edu or 603-646-3274 or Elsevier’s Newsroom at newsroom@elsevier.com or +31-20-4853564.

About Vaccine

Vaccine is the pre-eminent journal for those interested in vaccines and vaccination. It is the official journal of The Edward Jenner Society, The International Society for Vaccines and The Japanese Society for Vaccinology. www.elsevier.com/locate/vaccine

The study's co-authors are available to comment. For more information, Brendan Nyhan can be contacted at brendan.j.nyhan@dartmouth.edu or on his cell phone at +1 (919) 452-6451. Jason Reifler can be reached at j.reifler@exter.ac.uk or on his cell phone at +44 (0)7831 152405.