Will conspiracy theories on Twitter hamper Zika vaccine?

Researchers warn that misinformation and conspiracy theories posted on Twitter could undermine efforts to deliver a Zika vaccine.

The team analyzed thousands of Twitter posts and found pseudoscientific assertions and claims of shadowy plots that they say could cause vulnerable people to refuse Zika vaccinations when they do become available.

“Even though the science is relatively clear, we found many conspiracy theories that could be affecting people’s health-related decisions, such as whether to vaccinate.”

Among the false claims on Twitter were that Zika-linked brain defects in newborns are actually caused by existing vaccines for other diseases, but that drug companies are blaming Zika to open a market for a new vaccine. Another theory spread on social media is that an insecticide, not Zika, is really to blame for the brain condition, called microcephaly.

“Once people have made up their minds about something, it’s hard for them to change their opinions,” says Mark Dredze of Johns Hopkins University, lead author of the study published online by the journal Vaccine. “I’d find it surprising if this sort of [social media-disseminated] story really had no impact whatsoever, and I can’t imagine it would make people more likely to pursue a healthy response.”

The researchers—from Johns Hopkins, George Washington University, and the University of Georgia—are encouraging public health authorities to use real-time social media monitoring to track and respond quickly to unsubstantiated claims.

Although development of a Zika vaccine is in its early stages, “there is already cause for concern regarding the success of the eventual vaccination campaign,” the research team writes in the study.

140,000 tweets

The Zika virus is spread by mosquitos and through sexual intercourse, but most patients suffer only mild flu-like symptoms. The US Centers for Disease Control and Prevention, however, says that infection of pregnant women can later result in babies born with microcephaly, with abnormally small heads and brains. A different group of Johns Hopkins researchers led a recent emergency study identifying how the virus may be causing the birth defect.

Dredze, an assistant research professor in computer science at Johns Hopkins, has collected and analyzed social media data to monitor flu cases, mental illness trends, and other health concerns.

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To investigate the scope of the Zika-related claims, he and the team monitored Twitter to identify relevant conversations as soon as they happened. They found nearly 140,000 tweets between January 1 and April 29, 2016, that contained the keywords “vaccine” and “Zika.”

“Even though the science is relatively clear, we found many conspiracy theories that could be affecting people’s health-related decisions, such as whether to vaccinate,” says corresponding author David Broniatowski, assistant professor in the School of Engineering and Applied Science at George Washington. “Unfortunately, the people most affected are from the most vulnerable communities, with little access to the facts.”

The researchers say public health experts must quickly address people’s concerns and debunk unscientific claims to ensure a future vaccine campaign is effective.

“Shortly after Zika rose to prominence, we were able to track these conversations very quickly using our social media monitoring method,” Broniatowski says. “This is a promising approach to the fast response to disease, and could help counteract the negative impact of these conspiracy theories in future.”

The third researcher involved was Karen M. Hilyard, assistant professor of health communication at the University of Georgia College of Public Health. The National Institutes of Health supported the study.

Source: Johns Hopkins University

DOI: dx.doi.org/10.1016/j.vaccine.2016.05.008