BOB GARFIELD:  From WNYC in New York, this is On the Media. Brooke Gladstone is away this week. I’m Bob Garfield.

  [CLIPS]:

MALE CORRESPONDENT:  The first baby with Zika-related birth defects has been born in the New York City Tri-State area.

FEMALE CORRESPONDENT:  The baby girl was born with the telltale signs of Zika, a small head and partially-developed brain.

FEMALE CORRESPONDENT:  Doctors at Hackensack University Medical Center say the child was born to a mother from Honduras yesterday. The woman gave birth while vacationing though here in the United States.

  [END CLIP]

BOB GARFIELD:  As the virus spreads, so do fears. Last Friday, a petition signed by more than a hundred doctors and health experts worldwide urged the World Health Organization to call for moving or postponing the Summer Olympics from Zika-plagued Brazil. The WHO, along with the US Centers for Disease Control, say there is, so far, no public-health justification for such drastic action. So naturally, into the vacuum of official uncertainty rushes - pseudoscience and paranoia.

Mark Dredze is an assistant professor of Computer Science at Johns Hopkins University and the lead author of a new study about Zika virus-related conspiracy theories. He and his team had spent a lot of time looking at social media to understand why people refuse vaccines, and earlier this year they noticed that Zika chatter had started to show up in anti-vaccine threads. After separating out those sharing reasonable information about Zika from those sharing misinformation, the researchers built a computational algorithm that could learn to tell the difference.

MARK DREDZE:  When we ran that over about 140,000 messages, there were really two dominant theories that were being spread. One was that Zika was not at all the cause of the birth defects that we were seeing, rather they were the side effects from a vaccination campaign in Brazil, which is obviously untrue. The  other theory that we saw was that Zika was actually the result of genetically-modified mosquitoes, some part of a mosquito eradication campaign that had gone awry. There is an active anti-GMO population, there’s an active vaccine refusal population. And that’s what makes this so much more concerning. If it was just a conspiracy theory that no one really believed and couldn’t gain traction, we wouldn't worry about it. But because it fits an existing narrative where you already have a group that believes it, it gives it the air of credibility, and it’s more likely to spread in the population to people who don't believe these things, in the first place, but are genuinely concerned and go online to find information about Zika.

BOB GARFIELD:  There’s certainly no shortage of subject matter that people want to impose their own explanations for. Some of this stuff is so insane. [LAUGHS] Airplane contrails?

MARK DREDZE:  There are really crazy theories out there, whether it's airplane contrails, the idea that somehow the government is trying to manipulate the population through covert chemical spraying or Americans are naturally immune to Zika or that Bill Gates is behind some kind of bio weapon that led to this. This is a virus that, while it’s existed for a very long time and we've known about it for a long time, the side effects we’re seeing now are really new. And when it first happened, there was legitimately a lack of information in the scientific community about exactly what was going on.

When people lack credible information, they go out to find whatever information is there. And we need to make sure that we combat that information so that we can spread proper medical information to people who really are trying to just figure out what's going on.

BOB GARFIELD:  So, as we've established, there is a certain population that believes that there is a conspiracy between government and Pharma to make vaccines, irrespective of their negative effects, and the Zika outbreak is just one more smoking gun. As you say, they're not going to be disabused of their paranoia. The question is, what can be done to keep their ravings from infecting others?

MARK DREDZE:  Well, I think the only counter to misinformation is accurate information, and that's why public health organizations like the CDC spend so much time trying to inform the public, whether it's on their website or through social media campaigns. I think, in this context, the news media does have an important role to play. The normal inclination is that every subject has two sides, but in the context of medicine there is often an objective truth. And so, when it comes to reporting on diseases like Zika or Ebola or childhood vaccinations, if we do include information that the medical establishment knows is not true, these pseudoscientific theories, then we should pay attention to how much time we give it and how it's being framed.

If we have an anecdote about a child that was harmed from a measles vaccine and then we follow it with statistics about the dangers of measles, we should make sure that the time allocated to both really conveys that the side effects of measles vaccines is exceedingly rare, whereas the dangers of measles are really quite real. Oftentimes, we get bogged down in anecdotes and statistics, and people lose the big picture. We need to come back to this clear message that, in this case, Zika is dangerous and you should take preventative steps to prevent you or your family from contracting it.

BOB GARFIELD:  All right, I understand what you say but, as you know, there is research – I think it was done by the CBC itself - that says the harder public health officials work to debunk false claims, the more those false claims are cemented in the minds of the public, that the education campaigns actually can be counterproductive. If that's true, what is a public health ecosystem to do?

MARK DREDZE:  That is certainly a problem. I think though there’s a larger population of people who really are undecided, people who don't know, that are really going out there to seek what is the best thing to do. So let’s take childhood vaccinations. There are a lot of people who have kids and they go to the doctor and it's time to give their child the vaccine, and they generally don't have preconceived notions. So they go online or they talk to their friends and they start looking for information. It’s those people that I think we have a good job of convincing. We want to make sure that they don't form the impression that, while some people say vaccines are dangerous, some people say they’re safe, therefore, I don't know what to do, I’m gonna err on the side of safety. We want to make sure they understand that overwhelmingly the medical establishment says vaccines are completely safe and that they shouldn’t be  misled by these pseudoscientific theories. We should focus on trying to inform that population.

In the case of Zika, that population is really large because people don't know what Zika is and they’re really exposed to it for the first time. So I think, in that context, proper messaging by the medical establishment and public health officials can have a really big impact.

BOB GARFIELD:  Mark, thank you very much.

MARK DREDZE:  It’s been my pleasure, Bob.

BOB GARFIELD:  Mark Dredze is an assistant researcher of Computer Science at Johns Hopkins University and lead author of the study, Zika Vaccine Misconceptions: A Social Media Analysis.