Researchers investigated the effectiveness of health information campaigns to correct public misperceptions during disease outbreaks in Brazil.
During disease outbreaks, a surge of news and public discussion can often lead to misperceptions and conspiracy theories about the disease. Incorrect messages compete with accurate information and advice given by public health bodies. This may mean that the public take misguided inappropriate actions that do not protect them or prevent disease spread.
It is essential that health information campaigns are effective in correcting public misperceptions in disease outbreaks, so it is important to evaluate their impact. Researchers at Dartmouth College, USA, assessed the effectiveness of health information campaigns to counter myths about Zika virus and yellow fever in Brazil. They recently reported their findings in Science Advances.
Conspiracy theories often develop during disease outbreaks
In May 2017, while the Zika virus outbreak was ongoing in Brazil, the researchers conducted a face-to-face survey with over 1,500 participants to measure the prevalence of misperceptions and conspiracy beliefs about the virus. The survey included questions about the causes and consequences of the Zika outbreak, beliefs in conspiracy theories and misperceptions, support for disease control policies, preventative behaviors, and the perceived threat of Zika virus. To avoid influencing responses, the questions used neutral language rather than words such as “conspiracy theories” or “misperceptions”.
The researchers then conducted three online survey experiments. Two surveys (in 2017 and 2018) tested the effectiveness of public health messages aimed at countering conspiracy theories and misperceptions about Zika virus. A further survey (in 2018) tested the effectiveness of public health messages about yellow fever following a severe outbreak. Yellow fever is a more common disease in Brazil than Zika virus, so the disease is better-known.
Health information campaigns to counter Zika virus myths not effective
The Zika virus face-to-face survey showed that most Brazilians correctly understood the role of mosquitoes in spreading Zika and that the virus was not spread by casual contact. However, just 40% understood that Zika can be passed by sexual contact. In addition, more than 63% of Brazilians agreed with the misperception (as part of a conspiracy theory) that the spread of the disease was due to genetically modified mosquitoes and just over 50% with the misperception that the surge in cases of microcephaly in newborns (a malformation of the brain caused by Zika virus) was due to pesticides and prenatal vaccination.
The online survey experiments showed that corrective health information campaigns to counter conspiracy theories about Zika virus not only failed to reduce misperceptions, but also frequently reduced the accuracy of true beliefs about the disease. The online survey experiment on the better-known disease yellow fever showed that corrective information was more effective. However, the corrective information campaigns for both Zika and yellow fever did not affect support for disease control policies or intention to adopt disease prevention behaviors.
Alternative approaches needed to combat myths during disease outbreaks
“Our results indicate that efforts to correct misperceptions about emerging diseases like Zika may not be as effective as we might hope,” said Prof. Brendan Nyhan, a co-author of the study. The study gives useful insights as countries develop public health information campaigns about the new coronavirus (COVID-19).
More research is needed to understand the prevalence of conspiracy theories and how best to counter misinformation. The authors suggest that public health specialists should have realistic expectations about the effectiveness of health information campaigns. Alternative approaches that do not try to directly debunk disease myths may be needed. For example, encouraging the public to participate in educational programs, or developing high-profile public prevention and protection measures. The authors conclude that in some cases, the best way to defeat misperceptions may be to avoid challenging them directly.
Written by Julie McShane, MA MB BS
1. Carey JM, Chi V, Flynn DJ, et al. The effects of corrective information about disease epidemics and outbreaks: Evidence from Zika and yellow fever in Brazil. Science Advances 2020:6:eaaw7449. Doi:10.1126/sciadv.aaw7449
2. Dartmouth College. Press release 27 Feb 2020. “Lessons learned from addressing myths about Zika and yellow fever outbreaks in Brazil. https://www.eurekalert.org/pub_releases/2020-02/dc-llf022720.php
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