It's not often that you find a literary essayist wandering into contemporary political debates, these days. But in her new book On Immunity: An Innoculation, Eula Biss wades calmly, lucidly into a subject that has most people screaming in under 15 seconds on talk shows: vaccination.

Biss writes with measured prose and careful research, skills in generally short supply in our aggregated, hyper-aggressive culture of argument. (Her last book of essays, Notes From No-Man's Land, won the National Book Critic's Circle Award for Criticism.) On Immunity is digressive and philosophical. From it you'll learn that some of the earliest immunization techniques were as crude as shoving knitting needles laced with pus into people's arms, and then in the next passage be taken through Biss' own experience as a mother trying to decide whether or not to immunize her son.

Biss spoke to me by phone about her book and her arguments, and she will be here in the comments at 10:30 a.m. EST to answer your questions.

So! Ultimately you came out believing that vaccination does not cause autism.

Yeah, that's an area where the science is pretty clear. There's still a pretty vivacious social debate around that but there's no scientific debate on that anymore. The science is kind of closed.

You have, with this book, intervened in that public debate in a pretty anti-pundit way, though.

In this area, I feel really strongly that's what we need. More and more, it seems like both sides are getting really reductive, and ironing out the nuances of the conversation. There seems to be a proliferation of pundits.

Obviously on what I'm just gonna call the Jenny McCarthy side, the reduction is a lack of attention to the science. What about the other side?

On the pro-vaccine side — and not everyone does this but I saw it enough for it to make me really uncomfortable — is a tendency to accuse people who are wary of vaccination of being stupid and not understanding science. For most people who are hesitant about vaccination, a lot more is going on. I talked to lots of people who are vaccine-hesitant, and I actually was one myself until I got further into this project, and most of them actually are in my demographic: so well-educated people with advanced degrees, who are upper middle-class and have read quite a bit on the subject.

So not only is it reductive, I think it's also wrong. I think if we're really concerned about stopping falling vaccination rates, we also need to be concerned about the actual reasons why those rates are falling, and not just write it off to stupidity.

Can you talk about herd immunity? In the book you refer to it repeatedly to suggest we could be close to a tipping point.

Herd immunity is, it turns out, not incredibly easy to understand. It took me quite a bit of reading before I fully grasped it. But understanding herd immunity is essential to understanding why we vaccinate the way we do. Meaning, we do quite a bit of mass vaccination, and the reason is that many vaccines are intended to protect only a small segment of the population that is vulnerable to that disease. And the reason is, that small segment that is particularly vulnerable can't be vaccinated, or vaccination doesn't work well for that segment.

Pertussis is a great example. The babies that are most vulnerable to pertussis and that are most likely to die from it are too young to be vaccinated. So in that 2010 epidemic in California, 10 babies died. 9 of them were too young to be vaccinated. And actually the 10th was a premature baby in a more complicated case.

So what we do is we vaccinate just about everyone else, and what that accomplishes, if vaccine acceptance rates are high enough, is it takes the organism out of circulation. The organism just doesn't have enough hosts to move through a population. And depending on the contagiousness of the disease, we can vaccinate only 85 or 90 percent of the population and actually get 100 percent protection against the disease.

That is not true for pertussis. Pertussis is very contagious, and we actually need to get pretty close to 99 percent of the population to create herd immunity for the other one percent. Other diseases like diphtheria, for example, we just don't have in the U.S. right now. That's not because every single person is vaccinated. But enough people are vaccinated that that disease does not circulate among the population.

You connect this out to concepts of individual and collective responsibility, or the body natural and the body politic. Would it be fair to say you believe that there's a political responsibility to vaccinate?

Political would be one way of putting it, or social, or moral, depending on what you think your moral responsibilities are to other people. Yeah, I do think there's a responsibility.

One of the medical ethicists that I was speaking to, she said something along the lines of, "I just believe that when you're a member of society there are certain things you owe that society." In this case we have the tools to prevent our bodies from being vectors for disease. And if we have the tools, and they're good tools and highly effective, which [vaccines] are, that it is our responsibility to make our bodies invulnerable to disease. Or to make our bodies not vectors for disease to other people.

There's this tendency to think of the individual and the collective are somehow at odds or separate. But I think that's really false. We're all both. And when the individual suffers, the collective suffers, and vice versa. And that's not just a point I believe philosophically, but it's also something that's been observed by mathematicians who look at vaccination, and do mathematical modelling of it. They observe that statistically speaking, you are benefiting both yourself and the collective when you vaccinate yourself against something like the flu. So it's not like we have to make a sacrifice as an individual in order to protect the collective.

Reading your book I kept wondering how this intersects with the rhetoric of motherhood, or where we are with feminism and motherhood for you. A lot of people are very hesitant to impose some responsibility to the collective on mothers. Because they feel like it's hard enough.

I do think it's hard. We impose all kinds of things on mothers. And actually, you know, of all the identity groups that I belong to, motherhood and mothering are the most restrictive. It's quite a restrictive space. For the most part many of those restrictions are unnecessary, and some of them are even misogynist in nature. Or, you know, just hateful and restrictive, there's almost no benefit.

But the reality is part of what makes mothering so difficult — and parenting in general, this isn't just women, fathers get it a lot easier — is that you are charged with some fairly dramatic responsibilities. And one of those responsibilities is the raising of a citizen, and taking a kind of wild, unsocialized being and bringing them up to function in society. You're not alone in that, you've got schools and you've got your community, but it's also on you to ensure that your child can function as a citizen.

And that's where I feel like it's legitimate for us to examine what they're doing around vaccination. Because it is a question of citizenship. That can get forgotten as we get more and more isolationist in the way we approach parenting and families. There's so much emphasis on making it a perfect world within the home, on making it non-toxic and sealed off from the world and safe in every way. It becomes this bubble we bring up the child within. And the more we bubble ourselves, we let ourselves pretend that we can create an alternate little world in the home. It lets us forget the ways in which we are essentially dependent on the community at large and what we owe the community at large.