Why Doesn’t Everyone Get the Flu Vaccine? A New Freakonomics Radio Podcast

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(Photo: KOMUnews)

(Photo: KOMUnews)

What if there were a small step you could take that would prevent you from getting sick, stop you from missing work, and help ensure you won’t play a part in killing babies, the sick, and the elderly?

That actually exists: it’s called the flu shot. But a lot of people don’t get it. Why? That’s the question we try to answer in this episode of Freakonomics Radio. (You can subscribe to the podcast at iTunes or elsewhere, get the RSS feed, or listen via the media player above. You can also read the transcript, which includes credits for the music you’ll hear in the episode.)

Influenza and pneumonia, which the Centers for Disease Control groups together, have long been among the top-ten annual killers in the U.S. In 2010 (the most recent year for which there is final data), the count was an estimated 53,826 Americans — more than six times the number of worldwide deaths from Ebola last year.

In the episode, you’ll hear Jeff Kwong, an epidemiologist, family physician, and researcher at the Institute for Clinical Evaluative Sciences, explain the science around influenza and its vaccine. In an ideal world, Kwong says, the vaccination rate would be 100 percent. But in reality, as he tells Stephen Dubner, it’s less than half that in the U.S. Why?

KWONG: I think one of the problems with influenza is the perception that it’s not a big deal. And it’s true that for most people it isn’t. … But then the problem is that they could be giving it to their elderly parent, or their young child, or their pregnant wife. And then their infant is born premature as a result of the influenza infection. … So that sort of thing plays out and it doesn’t make headlines, but that’s the reality people don’t appreciate.

Frederick Chen, an economist at Wake Forest University, designed an online game to try and decipher the incentives people need to get vaccinated. While he admits that the game is not “super fun,” he argues that it provides some evidence for the kind of ideas that policymakers should pursue to boost vaccination rates.

Chen thinks one reason many people fail to get a flu shot is because of a psychological shortcut known as the  “availability heuristic”:

CHEN: And so that means, the more salient, or more vivid something is, the easier it is for us to recall. … For instance, if we see an earthquake happening in the news, then somehow, because that’s very vivid, we tend to overestimate the probability of an earthquake occurring. … And so, I think the problem with vaccination in the end comes down to this: When it’s working, it’s not very memorable.  … It’s more newsworthy when we see things not working.  But when a vaccine is working, nobody wants to talk about it.

There’s also a sizable group of people with “vaccine hesitancy,” who generally dislike the idea of immunization. Some of these skeptics hold beliefs about vaccines that are demonstrably wrong — but they are hard to budge. Research by the political scientists Brendan Nyhan and Jason Reifler, for instance, shows that when such people are given scientific information to dispute vaccine myths, they become less likely to get the vaccine.

Vaccine skeptics will hardly be comforted by the bizarre true story of how the CIA used a Pakistani vaccine campaign as cover during the hunt for Osama Bin Laden. You’ll hear all about it from Mark Mazzetti, a Pulitzer-winning New York Times reporter who chronicles the saga in his book The Way of the Knife: The CIA, a Secret Army, and a War at the Ends of the Earth.


Another reason people may not get it is because of experiences that others have. For example, I get the flu shot every year. This year, after I got the shot, I got the flu twice. The CDC missed the strains that actually are going around, so while the shot appeared to shorten the flu length (thank goodness), it still reinforced preconceived notions that people have about the shot. Thus, people who haven't gotten it before look and say "You see. He got the shot and still got the flu!" Doesn't matter that I missed getting the flu the prior 10 years because they didn't see that. Sad but true.


This vaccine doesn't prevent anything. It reduces the chances of catching the flu. If the vaccine could be administered after flu season passed, and strains were identified, it would be more effective. That is not how it works though. If everyone got a flu shot, the flu would not be eradicated. Failure to mention this seems as ignorant/naive as any other part of the conversation.

Phil Persinger


The key word the CDC uses regarding the various flu vaccines is "protect."


I'm not sure that any vaccine is 100% effective in preventing its particular target disease. The yearly formulation for the flu shot represents the best guess about which viral strains will be dominant during the coming season.

You're correct, then, that universal vaccination would not eradicate the disease. Still (and I hope you agree about this) it makes sense to consider getting a flu shot-- if only because one might be in close contact with an elderly relative or someone with an immunity disorder.


For me it's a change in the way I think of vaccines. Vaccinations for me are something that we got as infants (and that I gave my infants) that protect us for life. Getting the "same" vaccine every year is weirder for me. ( i know it's not the same but it's named the same) When the vaccine for H1N1 was offered it was clear that it was a vaccine for H1N1. The generic naming of the vaccine is tough for me but I also know that the numbers that these vaccines go by would quickly become irrelevant to me as well. I don't have a solution but there you go. You have convinced me. There was one woman interviewed who mentioned that she would not tell her kids to do as she was doing (not getting the shot). I think I need to teach my kids the habit of the getting the vaccine every year it's offered.


I don't get the flu. Why get the shot?


Because someday, you WILL get the flu, and you risk giving it to some poor infant who was too young to get the vaccine, or to a child with an immunodeficiency or cancer. Is it worth it?


I am an RN and work at a pediatric office in a wealthy resort town. Our patient population is far removed from many of the discomforts of the world. We administer "Flu-Mist," to everyone over age 2 without severe asthma- it is inhaled through each nostril. Flu-mist lasts for an entire year, and most of all, does not hurt. We provide it to parents, nannies, and pretty much anyone who stops by, no appointment needed. It is very quick, and thanks to our new health care law, free. I wish your show would have discussed how due to the new health care law, all vaccines are covered at 100%. Making all vaccinations free, painless and convenient encourages compliance. Another strategy to increase compliance of all childhood vaccinations involves parents with vaccinated children inquiring of the vaccination status of other children. Unfortunately, we treat dogs with a higher regard than children- dogs are required to show proof of vaccination to be licensed or to stay at a kennel. Not vaccinating a child is a symptom of a spoiled society who refuses to learn from the lessons of the past. That is why we are seeing an increase in preventable diseases such as measles and pertussis. Babies are not able to receive the pertussis vaccine until two months of age- pertussis can be fatal to unvaccinated infants. I have two acquaintances with completely unvaccinated children. BOTH kids flew on a loaded jet (separate times) with incessant coughing due to pertussis. Obviously both sets of parents had no consideration for the other people on the plane who may have become infected- it is an interesting type of person who will let their kid run around, unvaccinated. Over the past seven years, there continues to be an increase in this reckless, irresponsible, selfish, ignorant behavior.



Well said. As a pediatrician, I agree - it's flat-out selfish not to vaccinate. Even if you, personally, don't' care if you get sick, it's still everyone's responsibility to protect the patients who can't get vaccinated themselves - the kids with immune deficiencies, the kids with cancer, infants who are too young. Decisions about whether or not to vaccinate affect EVERYONE.


What, if any, impact is there when a shortage of the flu vaccine is announced? In the years where there is a shortage, I will usually make the decision to forgo the vaccine and leave it for the elderly and babies. What I find happens is so many healthcare providers stock up to the point they have to give it away. In my career I work with lots of paramedics, nurses and other public health workers. It seems like in the shortage years, I am constantly offered the vaccine whereas in non-shortage years I have to seek it out. Does the shortage have any impact, positive or negative on vaccination rates since the shortage becomes headline news and everyone is talking about the vaccine and yet I never see anyone actually run out.


In response to the comment about trying to appeal to people's altruistic nature, why don't we see more campaigns to have people "donate" a flu vaccine to someone who can't afford one? I get hit up all the time at the grocery store to donate to other public health causes. For those who don't have health insurance (where the vaccine would be free), I would be willing to pay $30 for someone else to get one.

Human as you

no mention is made on the ingredients... FAIL
One of the interviewed clearly stated she got the flu every time she got the shot...


I really enjoyed this episode, but wish it had gone into more detail regarding "Vaccine Paranoia" and the relevant science there. After all, this seems like the biggest of the four reasons hindering wider adoption of vaccines in today's world.

Unfortunately, it seemed like the fear produced by the debunked autism scare was used to write off the bigger questions in that realm. For example, what about the secondary ingredients used in vaccines? The one I am most concerned about is the common use of Aluminum, which has been proven toxic above certain levels... levels which are far exceeded when administered to infants.

Some quotes:

"Recently, however, aluminum toxicity has increased precipitously. Today, nearly 80% of those tested for metal toxicity reveal excessively high hair aluminum levels."

"...with intravenously infused aluminum, 40% is retained in adults and up to 75% is retained in neonates."

"infants who were given IV solutions with aluminum showed impaired neurologic and mental development at 18 months, compared to the babies who were fed much lower amounts of aluminum. Those who got aluminum received an average of about 500 mcg of aluminum spread out over an average of 10 days. This comes out to about 50 micrograms per day. The babies who got the solution with aluminum filtered out received about 10 mcg daily, or 4 to 5 mcg per kilogram of body weight per day."

Any chance Freakonomics might do a follow-up? I always love hearing your approach to stuff like this. Keep up the good work guys!


Leon E Lewis

Your out of context excerpt omitted the crucial detail that the results of the infant study were from prolonged daily injections. That's significantly different from a single annual infection. It's misleafing to quote data in such a manner because the risks are completely different.

Madison Kobalt

Unfourtanely, you also do not consider the percentage of the population which experience a very severe or allergic ration to the vaccine. It took 2 shots during my first decades to determine that I was one of a number of people for who the shot is more of a threat than the flu. With precautions, I have been able to be shot free without catching the flu for 20 years.
Please practice good hygiene!


If science is science and it's silly to argue against the benefits of the flu vaccine why are the US and Canada the only countries in the world that recommend mass flu shots? There isn't a single European or Asian Health Department that recommends such a thing. http://www.cnn.com/2013/01/17/health/flu-vaccine-policy.


Everything here makes sense from the view of an economist, except that what isn't looked at are what goes into a vaccine. Literally, what goes into making a vaccine, and what exactly gets injected into human body?

Some known ingredients: trace amounts of metals like aluminum, for example. That's already been mentioned and argued about in older comments. What's one single dose seasoned with aluminum every year going to do? On its own, nothing, but it adds up when you consider how many other things manage to make it into the body. Between hard water and traces of pesticides in conventionally grown foods, it adds up. No, it probably won't kill you or poison you or make you blind. At least, not all at once. Research has shown that it will take its toll, but that research is often squashed because it doesn't warn of an extreme short-term issue. The accumulation of these particles doesn't kill you or harm you outright, but over time, they can with great effect.



I really enjoyed this program. There were many compelling points discussed. The one thing I didn’t hear but would love to hear more on is one more reason some people don’t get the shot – an allergy. I’m allergic to raw eggs. Raw eggs are used to make the flu vaccine (to incubate it). Because of this, my doctor has advised against taking it. I wonder what alternatives there might be though. I would love to get vaccinated if there were another option. Great show! Thanks.