Journalist Seth Mnookin's new book, The Panic Virus: A True Story of Medicine, Science, and Fear, explores the public health scare over vaccines and autism. The 1998 paper in The Lancet by British physician Andrew Wakefield that sparked the panic has long since been debunked and retracted, and Wakefield himself has been barred from practicing medicine and accused of fraud. But that hasn't stopped thousands of people from refusing to vaccinate their children out of fear that they could become autistic.

Mnookin warns of grave consequences. Recent outbreaks of measles, whooping cough, and other preventable infections have sickened thousands of children and killed more than a dozen in the United States. Vaccine rates are falling below the level needed to prevent an outbreak in a growing number of communities, including ones with wealthy, educated populations.

Last week, Mnookin spoke with ScienceInsider about why.

Q: There's a perception that vaccine refusal is especially common among affluent, well-educated, politically liberal parents—is there any truth to that?

S.M.: It's dangerous to make broad generalizations about a group, but anecdotally and from the overall data that's been collected it seems to be people who are very actively involved in every possible decision regarding their children's lives. I think it relates to a desire to take uncertainty out of the equation. And autism represents such an unknown. We still don't know what causes it and we still don't have good answers for how to treat it. So I think that fear really resonates.

Also I think there's a fair amount of entitlement. Not vaccinating your child is basically saying I deserve to rely on the herd immunity that exists in a population. At the most basic level it's saying I believe vaccines are potentially harmful, and I want other people to vaccinate so I don't have to. And for people to hide under this and say, "Oh, it's just a personal decision," it's being dishonest. It's a personal decision in the way drunk driving is a personal decision. It has the potential to affect everyone around you.

Q: But why liberals?

S.M.: I think it taps into the organic natural movement in a lot of ways.

I talked to a public health official and asked him what's the best way to anticipate where there might be higher than normal rates of vaccine noncompliance, and he said take a map and put a pin wherever there's a Whole Foods. I sort of laughed, and he said, "No, really, I'm not joking." It's those communities with the Prius driving, composting, organic food-eating people.

Q: In society as a whole, why does there continue to be so much fear of vaccines?

S.M.: I think there are a bunch of different answers to that. A really big one is that the fears of the repercussions of not vaccinating have become notional. Most people in our generation don't know people who had polio or don't know families where a child was blinded by rubella. So when there's any concern at all about vaccines, no matter how ungrounded in scientific evidence, it's like you're taking an infinitesimal risk against what almost seems like no risk.

Q: In the book you take the media to task for keeping the autism-vaccine "controversy" alive. Why?

S.M.: If there's one group that deserves blame for this it's the press. I completely understand where parents are coming from, both parents who believe their kids were harmed and parents who are worried about what might happen to their children. I don't believe the medical community and public health community have handled it well, but that wasn't out of incompetence or irresponsibility. The media did a horrible job and should have known better.

Q: How so?

S.M.: Well, for example, with Wakefield's initial Lancet paper, it should have been clear to any science reporter that there was no way to draw the conclusion he did from that study. Even if his data were reliable, even if none of the issues of selection bias and fraud had ever come up, drawing huge, broad conclusions from a 12-person case study is absolutely preposterous. The story in the next day's paper should have been what is this researcher doing, making these public health recommendations that are irresponsible and don't have grounding in science. To use the excuse, as the media has done, that we're just presenting both sides of issue is a total cop-out.

Q: Are there broader lessons here about how bad information can become so pervasive?

S.M.: There was a University of Michigan study a couple years ago where subjects were given a list of 20 statements about the flu vaccine, 10 of which they were told [were] true, 10 of which they were told were false. Ten minutes later they could identify which were true with a high degree of accuracy, but that went down precipitously with time. So the results would seem to indicate that merely hearing something, even in the context of hearing it isn't true, that concept gets introduced into your mental framework in a way that lends you to give that idea more credence. You can see this with all sorts of urban myths.