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Here's Why Rational People Skip Vaccines Even When They Trust Science
Science Alert ^ | June 13, 2025 | Y. TONY YANG & AVI DOR

Posted on 06/15/2025 6:57:41 AM PDT by DoodleBob

When outbreaks of vaccine-preventable diseases such as measles occur despite highly effective vaccines being available, it's easy to conclude that parents who don't vaccinate their children are misguided, selfish or have fallen prey to misinformation.

As professors with expertise in vaccine policy and health economics, we argue that the decision not to vaccinate isn't simply about misinformation or hesitancy.

In our view, it involves game theory, a mathematical framework that helps explain how reasonable people can make choices that collectively lead to outcomes that endanger them.

Game theory reveals that vaccine hesitancy is not a moral failure, but simply the predictable outcome of a system in which individual and collective incentives aren't properly aligned.

Game theory meets vaccines

Game theory examines how people make decisions when their outcomes depend on what others choose. In his research on the topic, Nobel Prize-winning mathematician John Nash, portrayed in the movie A Beautiful Mind, showed that in many situations, individually rational choices don't automatically create the best outcome for everyone.

Vaccination decisions perfectly illustrate this principle. When a parent decides whether to vaccinate their child against measles, for instance, they weigh the small risk of vaccine side effects against the risks posed by the disease. But here's the crucial insight: The risk of disease depends on what other parents decide.

If nearly everyone vaccinates, herd immunity – essentially, vaccinating enough people – will stop the disease's spread. But once herd immunity is achieved, individual parents may decide that not vaccinating is the less risky option for their kid.

In other words, because of a fundamental tension between individual choice and collective welfare, relying solely on individual choice may not achieve public health goals.

This makes vaccine decisions fundamentally different from most other health decisions. When you decide whether to take medication for high blood pressure, your outcome depends only on your choice. But with vaccines, everyone is connected.

This interconnectedness has played out dramatically in Texas, where the largest U.S. measles outbreak in a decade originated. As vaccination rates dropped in certain communities, the disease – once declared eliminated in the U.S. – returned.

One county's vaccination rate fell from 96% to 81% over just five years. Considering that about 95% of people in a community must be vaccinated to achieve herd immunity, the decline created perfect conditions for the current outbreak.

This isn't coincidence; it's game theory playing out in real time. When vaccination rates are high, not vaccinating seems rational for each individual family, but when enough families make this choice, collective protection collapses.

The free rider problem

This dynamic creates what economists call a free rider problem. When vaccination rates are high, an individual might benefit from herd immunity without accepting even the minimal vaccine risks.

Game theory predicts something surprising: Even with a hypothetically perfect vaccine – faultless efficacy, zero side effects – voluntary vaccination programs will never achieve 100% coverage. Once coverage is high enough, some rational individuals will always choose to be free riders, benefiting from the herd immunity provided by others.

And when rates drop – as they have, dramatically, over the past five years – disease models predict exactly what we're seeing: the return of outbreaks.

Game theory reveals another pattern: For highly contagious diseases, vaccination rates tend to decline rapidly following safety concerns, while recovery occurs much more slowly.

This, too, is a mathematical property of the system because decline and recovery have different incentive structures. When safety concerns arise, many parents get worried at the same time and stop vaccinating, causing vaccination rates to drop quickly.

But recovery is slower because it requires both rebuilding trust and overcoming the free rider problem – each parent waits for others to vaccinate first. Small changes in perception can cause large shifts in behavior.

Media coverage, social networks and health messaging all influence these perceptions, potentially moving communities toward or away from these critical thresholds.

Mathematics also predicts how people's decisions about vaccination can cluster. As parents observe others' choices, local norms develop – so the more parents skip the vaccine in a community, the more others are likely to follow suit.

Game theorists refer to the resulting pockets of low vaccine uptake as susceptibility clusters. These clusters allow diseases to persist even when overall vaccination rates appear adequate.

A 95% statewide or national average could mean uniform vaccine coverage, which would prevent outbreaks. Alternatively, it could mean some areas with near-100% coverage and others with dangerously low rates that enable local outbreaks.

What's more, blaming parents for making selfish choices can also backfire by making them more defensive and less likely to reconsider their views.

Much more helpful would be approaches that acknowledge the tensions between individual and collective interests and that work with, rather than against, the mental calculations informing how people make decisions in interconnected systems.

Research shows that communities experiencing outbreaks respond differently to messaging that frames vaccination as a community problem versus messaging that implies moral failure.

In a 2021 study of a community with falling vaccination rates, approaches that acknowledged parents' genuine concerns while emphasizing the need for community protection made parents 24% more likely to consider vaccinating, while approaches that emphasized personal responsibility or implied selfishness actually decreased their willingness to consider it.

This confirms what game theory predicts: When people feel their decision-making is under moral attack, they often become more entrenched in their positions rather than more open to change.

Better communication strategies

Understanding how people weigh vaccine risks and benefits points to better approaches to communication. For example, clearly conveying risks can help: The 1-in-500 death rate from measles far outweighs the extraordinarily rare serious vaccine side effects.

That may sound obvious, but it's often missing from public discussion. Also, different communities need different approaches – high-vaccination areas need help staying on track, while low-vaccination areas need trust rebuilt.

Consistency matters tremendously. Research shows that when health experts give conflicting information or change their message, people become more suspicious and decide to hold off on vaccines. And dramatic scare tactics about disease can backfire by pushing people toward extreme positions.

When parents understand that vaccination protects vulnerable community members, like infants too young for vaccines or people with medical conditions, it helps bridge the gap between individual and collective interests.

Health care providers remain the most trusted source of vaccine information. When providers understand game theory dynamics, they can address parents' concerns more effectively, recognizing that for most people, hesitancy comes from weighing risks rather than opposing vaccines outright.


TOPICS: Health/Medicine; Science; Society
KEYWORDS: authoritybias; gametheory; vaccines
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To: T.B. Yoits

Why should Fauci decline a pardon that he most likely sought and paid good money for?


41 posted on 06/15/2025 8:25:53 AM PDT by FamiliarFace (I got my own way of livin' But everything gets done With a southern accent Where I come from. TPetty)
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To: DoodleBob
"Game Theory" has nothing to do with it when the people pushing the vaccine have already gone on record as advocating the use of vaccines to reduce the world's population.

I've heard that vaccines originated from someone noticing that "milk maids" exposed to cows with "cow pox" had become immune to the smallpox virus. If I were suddenly transported to that time/place I'd be rubbing up against those cows 24x7!

So, for rme, it ain't the vaccines .. it's the "vaccinators" that I don't trust.

42 posted on 06/15/2025 8:29:54 AM PDT by The Duke (Not without incident.)
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To: DoodleBob
There is a difference between trusting Science and trusting Scientists.
Science may be wrong but will correct itself eventually.
Scientists are prone to bias and corruption.
Even more so when Politics is demanding we obey the "correct" science of the moment.

Covid brought this all to the front.
Scientists lied. Politicians lied.
Articles like this still suggest that people are anti vaxx because they are anti science, or don't understand science and math.
It just adds to the lies.
I for one decided that the risk of the vaxx was greater than the risk from a bout of flu, something I have recovered from many times before.
I didn't have the numbers to back it up, but it was obvious even back in 2021 that there was something very wrong with the numbers we were given.

43 posted on 06/15/2025 8:30:37 AM PDT by BitWielder1 (I'd rather have Unequal Wealth than Equal Poverty.)
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To: DoodleBob

That’s an awful lot of words to just say waiting for clinical trial results.


44 posted on 06/15/2025 8:33:08 AM PDT by enduserindy
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To: T.B. Yoits
Tony Yang and Avi Dor are filthy propagandists. I thought I read some sick propaganda over the last five years but this is a whole other level. These two need to be hauled in for trial at Nuremberg II. The first question they need to answer is who wrote this for them, because this isn't from scientists or researchers, this is from professional propagandists.


When outbreaks of vaccine-preventable diseases...

Prove that the disease is vaccine-preventable, a term which doesn't exist. The pharmaceutical korporations and their shills looked straight at the cameras and insisted "If you take the shot, you will not get COVID." and "It's 100% effective."

...it's easy to conclude that parents who don't vaccinate their children are misguided, selfish or have fallen prey to misinformation.

Or they're actually well-guided and have avoided falling prey to actual disinformation campaigns from pharmaceutical korporations and their shills.

As professors with expertise in vaccine policy and health economics, we argue...

Notice they don't call themselves "experts" but instead "professors with expertise". Real slick there. Real trustworthy. Nice word play.

In our view,

And who's paying you to present that view? Let's see full disclosure, not like the rest of the pharmaceutical-government-industrial complex. Let's see every penny you've gotten and from exactly who. Let's see the USAID or other funding that's going to you through shell organizations. Let's see the board positions you were offered, not just the ones you accepted. Let's see the jobs you were offered, not just the one you accepted. Let's see the money given to your family members.

helps explain how reasonable people can make choices that collectively lead to outcomes that endanger them.

Call them reasonable but in the same sentence call them unreasonable by accusing them of choices that endanger themselves. Nice cognitive dissonance.

Game theory reveals that vaccine hesitancy is not a moral failure...

Imagine the irony of Godless, amoral people describing moral failure. Even the term "vaccine hesitancy" is immoral.

...outcome of a system in which individual and collective incentives aren't properly aligned.

So it's incentives, nothing more. "And you individuals should be looking out for the collective commune, not yourselves."

...to vaccinate their child against measles, for instance, they weigh the small risk of vaccine side effects

Small risk? If the risk is so small, remove the manufacturers' liability for the vaccine. Didn't think so. See, it's not "small risk" to the manufacturer but let's propagandize parents and insist it's a small risk.

...vaccinating enough people – will stop the disease's spread.

No. The "vaccine" wasn't a vaccine, regardless of what the CDC and their cohorts in pharmaceutical korporations changed their definition to. It didn't work. They knew it didn't work, and O M M O I R C O R N O I N C proved it.

But once herd immunity is achieved, individual parents may decide that not vaccinating is the less risky option for their kid.

Wait a minute. The same two authors just said it was a small risk. What is then a "less risky" option?

...relying solely on individual choice may not achieve public health goals.

And there it is. Such a gaslighting attack, that it was an individual choice, not an informed choice shared by millions, including THOSE WHO CREATED THE MRNA SHOTS.

...with vaccines, everyone is connected.

So the vaccine that was 100% effective doesn't work unless you take it also.

This interconnectedness has played out dramatically in Texas, where the largest U.S. measles outbreak in a decade originated. As vaccination rates dropped in certain communities, the disease – once declared eliminated in the U.S. – returned.

There are two lies here. Measles was never eliminated in the United States among groups who don't take the vaccination. It's a normal exposure for humans. The other lie is by omission; ignoring the illegal alien invaders who are exempted from requirements to get any medical treatments.

One county's vaccination rate fell from 96% to 81% over just five years.

It just fell with no explanation. It wasn't just hesitancy, it was watching what may be the largest crime against humanity carried out in the name of "science" and "health" by psychopaths.

...considering that about 95% of people in a community must be vaccinated to achieve herd immunity

Strange. They used to print that 80% was needed for herd immunity. So trustworthy.

...the decline created perfect conditions for the current outbreak.

Yes, the propaganda again of ignoring the illegal alien invaders.

...recovery is slower because it requires both rebuilding trust and overcoming the free rider problem – each parent waits for others to vaccinate first.

Rebuilding trust? Parents waiting for other parents? How about everyone waiting for the immunity for manufacturers to be removed? How about everyone waiting for the data and coverup information to be released?

Small changes in perception can cause large shifts in behavior.

Nice propaganda. It wasn't a "small change" and it wasn't just "perception" - it was a massive change of actual deaths and injuries. There are people dealing with actual health problems now, not just a "perception" of them.

A 95% statewide or national average could mean uniform vaccine coverage, which would prevent outbreaks.

Pure propaganda that deceptively posits that the vaccine works. If it's a bogus product, no percentage will prevent an outbreak, as O M M O I R C O R N O I N C proved.

Much more helpful would be approaches that acknowledge the tensions between individual and collective interests

Good. Let's start with the individual interests of stockholders, executives of pharmaceutical korporations, and those they paid off to promote defective injections. Let's see all the money they gained in their individual interests. Let's see how much of it was from taxpayers.

Research shows that communities experiencing outbreaks respond differently to messaging that frames vaccination as a community problem versus messaging that implies moral failure.

And there it is. Morality bad. "Commune-ity" good. Damn Communists once again. They can't control themselves.

The 1-in-500 death rate from measles far outweighs the extraordinarily rare serious vaccine side effects.

Who determines "serious"? Again, if the serious vaccine side effects are "extraordinarily rare", why are the manufactures immune from legal liability?

...high-vaccination areas need help staying on track,

Why would they need help staying on track? According to the authors, trust is high and side effects are low and extraordinarily rare.

...while low-vaccination areas need trust rebuilt

Rebuilt by whom? The same individuals who still hide data, cover up financial payments, lie about other diseases such as measles? No thank you.

Research shows that when health experts give conflicting information or change their message, people become more suspicious and decide to hold off on vaccines.

This is their sociopathic justification for censorship. Oh, and nice propaganda there: "hold off on vaccines". They're not vaccines and people are refusing them, not holding off on getting them.

And dramatic scare tactics about disease can backfire by pushing people toward extreme positions.

Scare tactics? Like when the President Potato of the United States publicly states that "if you don't get the shot, you're going to die"?

"Extreme" positions? Really. Imagine the utter gall of the propagandist behind this. THE EXTREME POSITION IS HIDING ALL THE DATA AND FORCING PEOPLE TO TAKE AN EXPERIMENTAL INJECTION.

When parents understand that vaccination protects vulnerable community members, like infants too young for vaccines...

Yeah, it's for the children... who were immune to COVID-1984 anyway.

..it helps bridge the gap between individual and collective interests.

There's that collective commune interests again. Damn sick Communists.

45 posted on 06/15/2025 8:36:02 AM PDT by T.B. Yoits
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To: Valpal1

And I think you’re overestimating it.

This is the essence of my response to the article.

I don’t think someone skips a vax because they think others are vaxed.

It comes down to one’s own assessment of the risks.


46 posted on 06/15/2025 8:42:40 AM PDT by fruser1
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To: DoodleBob
The fight is on one front “vaccination” but the bigger issue is editorial control of the dictionary. What the left calls “science” is simply an appeal to an authority fallacy. Science includes three elements: observability, repeatability, and verifiability. Much like how the hyphenated addition changes the word justice to mean injustice (ie social-justice) likewise words like climate-science are cloaks that proclaim the unscientific but with a cover as being “scientific”. It is a linguistic bait and switch, the claim to cloak the unscientific with the authority of science- that is the grift. The scientific method ALWAYS begins with skepticism toward every claim (hypothesis). There is no such thing as consensus, such a thing is what the scientific method is supposed to change.

But the other deception is the data. We have witnessed the falsifying of data, the statistical manipulation of data and elimination of data so much so that the data itself must be challenged or at least be treated with skepticism. This is especially true because the data is evidently manipulated to reach a political agenda.

47 posted on 06/15/2025 8:44:39 AM PDT by DaveyB (Live free or die!)
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To: BitWielder1

On the flu vaccines we did a simple experiment at our house.

I never got the flu vaccine for decades.

My wife got the flu shot every year.

She got the flu more and worse than I did.

The “scientists” can complain all they want about small sample size...I deeply don’t care.


48 posted on 06/15/2025 8:46:53 AM PDT by cgbg (It was not us. It was them--all along.)
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To: DaveyB

“The scientific method ALWAYS begins with skepticism toward every claim (hypothesis). There is no such thing as consensus”

Try explaining that to any science peer review team.

They are fanatics about maintaining whatever the current lies are—and demand total conformity.

That is one reason—as just one example—why modern physics is the mess that it is today.


49 posted on 06/15/2025 8:50:03 AM PDT by cgbg (It was not us. It was them--all along.)
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To: DoodleBob

“This interconnectedness has played out dramatically in Texas, where the largest U.S. measles outbreak in a decade originated. As vaccination rates dropped in certain communities, the disease – once declared eliminated in the U.S. – returned.”

And someone got measles…, like when we were kids


50 posted on 06/15/2025 8:54:08 AM PDT by DesertRhino (2016 Star Wars, 2020 The Empire Strikes Back, 2025... RETURN OF THE JEDI….)
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To: cgbg

We are both mid-70’s and very active around the community. The last “vax” either one had was the polio sugar cube.

I hit some flu in 2008. The lovely MrsProv1322 not at all.

Correction: we are vaccinated by The Blood of Jesus.


51 posted on 06/15/2025 9:01:22 AM PDT by Prov1322 (Enjoy my wife's incredible artwork at www.watercolorARTwork.com! (This space no longer for rent))
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To: DoodleBob

Please correct me if I’m wrong, but the COVID vaccine did not lower the rates of infected people transmitting the disease to others. So it’s wrong to think of “vaccine” in same terms as others. We shouldn’t have used the word vaccine.


52 posted on 06/15/2025 9:08:17 AM PDT by Mount Athos
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To: Valpal1

Interesting...I had warts all over my hands as a kid. The summer I was 12 a relative came for a visit...told me he would buy them from me for 50 cents...(this was early 60s). They were gone before I entered junior high that fall.


53 posted on 06/15/2025 9:14:56 AM PDT by goodnesswins (Democracy to Democrats is stealing other peoples money for their use, no matter how idiotic)
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To: fruser1

I know a lot of moms who skip vaxes because the are afraid of SIDS and autism. They aren’t super rational, most new moms aren’t.

I also know a lot of rape and molestation victims. It manages to be the most underreported (real) and overreported (a lot of fakes) of crimes.


54 posted on 06/15/2025 10:01:39 AM PDT by Valpal1 (Not even the police are safe from the police!!!)
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To: DoodleBob

The science supports vaccination. Some of the people we’ve voted into authority over vaccine development and implementation are criminally insane. They should be screened out and imprisoned .....some executed.

Start by retracting pardons signed in autopen by a mentally incompetent president.


55 posted on 06/15/2025 11:00:58 AM PDT by nagant ( )
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To: DoodleBob
Health care providers remain the most trusted source of vaccine information.

Yeah, right. Doctors are basically forced to parrot the party line on vaccines.

56 posted on 06/15/2025 11:18:19 AM PDT by Ford4000
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To: T.B. Yoits

I haven’t read a line-by-line critique like this since I was reading Ayn Rand critiques.

Bravo.


57 posted on 06/15/2025 5:18:40 PM PDT by DoodleBob (Gravity's waiting period is about 9.8 m/s²)
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To: DoodleBob
Thanks. That thing needed a line by line critique. It's one of the sickest things I've seen.

That was likely written by the best professional propagandists that the pharmaceutical korporations could bring in. I say that because it's written far better than regular propaganda. They built it word by word, phrase by phrase, and sentence by sentence. The word choice shows a lot of discussions behind them.

Y. Tony Yang and Avi Dor need to be facing trial and give up whose work they signed off as their own.

I expect this is just the beginning of the push turn blind people once again to what's these companies have been up to. These pharmaceutical korporations and their globalist cohorts are going to present more and more such "studies" and "opinions" as they try to regain ground on declining prescription drug use and so-called vaccines. They have an agenda and they're not going to stop. It's not just about revenue, it's about power.

58 posted on 06/15/2025 7:11:01 PM PDT by T.B. Yoits
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To: T.B. Yoits

“best professional propagandists”

Agreed. The information war is very real and it is 24/7.

I was one of those naive folks who thought the Internet would be a great way to educate people all over the world—and did not carefully consider the possible negative consequences.

It has turned into a brutal propaganda war on almost infinite fronts.


59 posted on 06/15/2025 7:24:58 PM PDT by cgbg (It was not us. It was them--all along.)
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