Conspiracy theories about vaccines, pharmaceutical companies and the origins of Zika spread online could endanger international efforts to stop the spread of the virus, which poses a threat to unborn children and pregnant women, among other vulnerable groups. Photo by Luiscar74/Shutterstock

WASHINGTON, May 25 (UPI) -- Researchers are becoming concerned conspiracy theories shared on social media could undermine the massive public effort to prevent the spread of the Zika virus, according to a recent study.

The international response to the spread of the Zika virus -- from verifying its links to health threats such as microcephaly to the development of a vaccine -- has been swift since it began to spread through the Americas in late 2015.


Researchers at Johns Hopkins University noticed, however, that as scientists have discovered how Zika is acquired by humans from mosquitoes and the dangers it poses, most notably to pregnant women and their babies, the number of theories and pseudoscientific claims found on the Internet only increased.

"Once people have made up their minds about something, it's hard for them to change their opinions," Dr. Mark Dredze, a researcher Johns Hopkins University, said in a press release. "I'd find it surprising if this sort of story really had no impact whatsoever, and I can't imagine it would make people more likely to pursue a healthy response."

In April, researchers at the U.S. Centers for Disease Control and Prevention announced they had confirmed Zika was causing babies to be born with very small heads and other developmental problems, including the death of fetal brain cells.

For the study, published in the journal Vaccine, researchers analyzed Twitter messages between January 1, 2016, and April 29, 2016, identifying 138,513 tweets containing vaccine keywords and a reference to Zika.

The researchers found the spread of fake science increased with the number of overall Zika-related tweets.

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They found many built on already existing narratives about the dangers of vaccines, calling the virus a side effect of vaccines such as MMR and DTaP, or that the virus was caused by a mosquito larvacide made by Monsanto. Neither theory has been shown to have any truth to it, however they persist online because people have already made their minds up on what they think, the researchers say the study suggests.

In further analysis, the researchers found 86 percent of Twitter users sharing pseudo-science tweeted about vaccines in 2015 and at least 19 percent of the tweets were anti-vaccine.

"While many in the public health and medical community view these sources as lacking credibility, they have been successful in advancing such tropes in the past, contributing to lower vaccination rates, infectious disease outbreaks such as the 2014/2015 Disneyland measles outbreak, and widespread concerns about vaccine safety," the researchers wrote in the study. "More troubling is that mainstream media sources are sharing many of these pseudo-scientific claims without examining the evidence behind them."

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The researchers say public health experts need to act faster to address and debunk inaccurate scientific claims about Zika, any vaccine created for it and other vaccines online, where the claims are shared. This could help tamp down the spread of false information.

In addition to experts and public relations professionals who work with them, the researchers suggest members of the media spend more time vetting sources and examining evidence, as well as not repeating incorrect information once it has been checked out.