TIME Research

Marijuana Does Not Affect Brain Volume, Study Finds

TIME.com stock health brain
Illustration by Sydney Rae Hass for TIME

The latest research adds to the debate over marijuana's effects on the brain

Using marijuana does not cause changes in brain volume, a new study suggests.

Public health experts have cited concerns that using marijuana could be associated with structural changes in the brain. However, a new trial comparing the brains of marijuana users and non-users to their siblings reveals that marijuana use likely does not cause changes in brain volume.

In the study, published in the journal JAMA Psychiatry, researchers looked at a large group of siblings ages 22 to 35. Of the 483 people, 262 reported ever using marijuana, even just once. The researchers then split the men and women into groups: sibling pairs who had never used marijuana, sibling pairs where both had reported using marijuana, and sibling pairs where one had used marijuana and one had not. Overall, they noticed that people who reported using marijuana had smaller volumes in certain parts of the brain—like the left amygdala, which is involved in emotional processing. However, these differences still fell within a range of volume that is considered normal.

The researchers hypothesized that in the sibling pairs where one had used marijuana and one had not, they would see differences in brain volume. But instead, they found that the exposed and unexposed siblings had the same amygdala volume. “We found no evidence for the causal influence of cannabis exposure on amygdala volume,” the authors concluded.

The researchers suggest that differences in volume could be due to other factors, like genetics or living environment. “Our study suggests that cannabis use, or at least the simple index of it that we used, does not directly impact changes in brain volumes,” says study author Arpana Agrawal, an associate professor at Washington University School of Medicine. “Instead, any relationship that we did see between cannabis use and brain volumes was due to predisposing factors that influence both cannabis use and brain volumes.”

The study did not find that brain volume has any effect on whether or not a person uses marijuana.

Another study, also published by different authors in the same journal, found that using marijuana could alter the brains of males at high risk for schizophrenia in potentially meaningful ways.

More research needs to be done to understand whether marijuana does or does not have potentially harmful effects on the brain, or whether the risks are different from one person to the next.

TIME medicine

Boy Who Had First Double Hand Transplant Leaves Hospital With New Hands

Zion with his new hands after the world's first bilateral hand transplant on a child at The Children's Hospital of Philidelphia.
The Children's Hospital of Philadelphia Zion with his new hands after the world's first bilateral hand transplant on a child at The Children's Hospital of Philadelphia

"The challenges facing Zion are new, but his determination should overcome them"

The first child to ever get a double hand transplant went home from the Children’s Hospital of Philadelphia Wednesday, his hands still bandaged but working well enough to let him play with action figures.

Zion Harvey, 8, lost his arms and legs to a life-threatening infection when he was just 2. He later needed a kidney transplant and was put on immunosuppressant drugs for the rest of his life. But this tragic medical history made Zion the ideal candidate to be the first kid in the world to get new hands.

“The challenges facing Zion are new, but his determination should overcome them. He’s already done so many amazing things,” Zion’s mom Pattie Ray said in a statement.

Read more from our partners at NBC News

TIME medicine

No, Selfies Aren’t Causing a Teen Lice Epidemic

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Caiaimage/Tom Merton—Getty Images/Caiaimage

One thing is for certain — we’re all taking more selfies than we ever have before. And while social science experts may debate what that says about us, doctors are more concerned about something else entirely: lice.

Lice, those tiny, barely visible parasites that can cling onto fur and hair, are more common in kids, who tend to have more head-to-head contact and share things like hats and helmets. But some doctors have been reporting — anecdotally — that they’re seeing more lice among teens. A few are, rather dubiously, are blaming selfies.

“People are doing selfies like every day, as opposed to going to photo booths years and years ago. So you’re probably having much more contact with other people’s heads,” Dr. Sharon Rink, a Wisconsin pediatrician, said on a local television show.

But there is no data showing the current lice outbreak—which is in 25 states and features lice resistant to the drugs usually used to kill them—is overwhelmingly affecting selfie-snapping teens, the National Pediculosis (that’s the official scientific name for a louse infestation) Association told the Huffington Post. The Centers for Disease Control says six to 12 million kids, aged three to 11 years, get lice in the U.S. each year. Children, and teens, are more likely to pick up lice during close contact in cars, during sleepovers, or sharing headphones, than they are in the few seconds it takes to take a selfie, say some experts.

And many of those raising the alarm have something to do with nit picking — literally. De-lousing salons have sprung up to help reluctant parents who cringe at the idea of tediously taking to the tweezers to pick out the critters, one by one. What better marketing message than to alert the public to a new population of hosts for the ever-hungry louse?

TIME vaccines

Here’s How the Anti-Vaxxers’ Strongest Argument Falls Apart

In session: The vaccine court—like vaccines themselves—stands by to help
Education Images; UIG via Getty Images In session: The vaccine court—like vaccines themselves—stands by to help

Jeffrey Kluger is Editor at Large for TIME.

The anti-vaxxers have been misrepresenting an important, if little-used, law

Scientists have long since learned to roll their eyes at politicians—especially when the topic is vaccines. Chris Christie and Rand Paul have both blundered into trouble with their support of vaccine opt-outs, a position that puts them at odds with virtually every medical authority on the planet. On Aug. 13, Carly Fiorina echoed a similar theme when she questioned “esoteric immunizations” like the HPV vaccine—which is a strange way to describe a shot that can save a woman’s life. All that, however, is just campaign-season noise.

Less noticed but perhaps more damaging was the moment in late July when Florida Republican Bill Posey rose on the floor of the House of Representatives and raised what has long been the anti-vaccine crowd’s biggest argument: the existence of a “Vaccine Injury Court.”

It’s at that point that the conversation often stops. The court—a federal panel that adjudicates payments to what the anti-vaxxers call “vaccine-injured children”—has long been the kryptonite, the dropped mic, the rapped gavel of any rational discussion of vaccine safety.

And no wonder: Since 1988, when the National Vaccine Injury Compensation Program (VICP) began, more than 16,000 claims have been considered and a whopping $3.18 billion have been awarded to families alleging some kind of harm from vaccines. That sounds awfully damning, and in this case, unlike in so many other cases, the anti-vaccine crowd isn’t just making stuff up. The numbers are real and the federal government is the first to admit it.

But the anti-vaxxers are utterly wrong in their interpretation of what the numbers mean. And in fact, the numbers prove that vaccines are as safe as the medical community says they are. Understanding why that’s so means going beyond the tired alarmism and looking at the facts.

The Court, Then and Now

The “vaccine injury court” is more properly known as the Office of Special Masters, which itself is a division of the United States Court of Special Claims. The special masters were created as part of the VICP, an act passed by Congress in 1986 and signed into law by President Ronald Reagan in 1988. It is a fundamental part of the anti-vax canon that the court is a closely held secret, established by Washington but kept as quiet as possible, lest the public catch wise to the fact that hush money is being paid to injured families.

“It is obvious that the government does not want to publicize the existence of the [court],” reads one website that is typical of the conspiracy wing, “because the more Americans learn that there are vaccine injuries and deaths … the more they may start to question the safety of vaccines.”

That, no surprise, is nonsense. The law was well-publicized at the time of its passage and is even better publicized today, thanks to a website set up by the Department of Health and Human Services (HHS), which not only explains the court in depth, but also provides the names and contact information of lawyers in all 50 states and offers detailed assistance in filing a claim.

The purpose of the court is to reckon with the reality that while vaccines are every bit as safe and life-saving as health authorities say they are, no drug or medical procedure is entirely without risks. Since many millions of children get vaccinated every year, even a few bad outcomes could subject the drug-makers to a storm of liability suits. Some claims might be legitimate, but far more could be frivolous or even fraudulent. Either way, the endless litigation could drive up the costs of vaccines.

In order to ensure that vaccines would be as affordable and available as possible, Congress thus created the VICP, establishing a trust fund for awards financed by an excise tax of 75 cents on every vaccine administered. Under the program, cases are adjudicated on a no-fault basis, with attorneys for the government and attorneys for the families arguing before one of eight special masters. The goal is to settle the matter as quickly and fairly as possible, though petitioners (the no-fault system avoids the word “plaintiffs”) who are unhappy with the special master’s ruling are free to take their case to the traditional civil court system.

The standard the petitioners must meet to recover any award is a comparatively low one—the “preponderance of the evidence” rule of civil law, rather than the “beyond a reasonable doubt” requirement of the criminal court system. In practice, that standard has been even more liberally construed in the vaccine court than it is in ordinary civil court, a fact that generally benefits the petitioners. More frequently still, things don’t go that far. In 80% of all cases brought since 2006, the parties settle, meaning that the petitioner recovers an award with no determination being made about whether the vaccine even caused the claimed harm.

“Settlements are not an admission by the United States or the Secretary of Health and Human Services…that the vaccine caused the petitioner’s alleged injuries,” says the HHS website. Claims may be settled for a lot of reasons, including “a desire by both parties to minimize the time and expense associated with litigating a case to conclusion; and a desire by both parties to resolve a case quickly and efficiently.”

Even without blame being established, the billions the government has handed over in payouts since the VICP was created does seem to suggest that a whole lot of people are being harmed. But that is not the case. From 2006 to 2014, approximately 2.5 billion doses of vaccines were administered in the U.S. In that time, a total of just 2,976 claims were adjudicated by the special masters and only 1,876 of those received compensation. Divide that number by the vaccine dose total and you get less than a one in a million risk of harm. Going all the way back to 1988—before the flu vaccine became part of the recommended schedule of vaccines—a total of 16,038 claims have been adjudicated and 4,150 have been compensated, bringing the total payouts up to the $3.18 billion figure.

To the anti-vaxxers, the low number of claimants spells its own kind of trouble. Divide overall payout by the relatively few injured parties and you get $766,265 per petitioner. The government wouldn’t hand over that kind of cash unless the injuries people do sustain are severe, right? Wrong.

Flooded With Injury Claims

The website of the U.S. Centers for Disease Control and Prevention (CDC) is very clear about any possible injury or side-effect that could possibly be caused by a vaccine (giving the lie to yet another anti-vaxxer claim that those risks are being covered up). The large majority of the possible problems are minor and transient—a fever, a short-term allergic reaction, soreness at the site of the injection. There is the possibility of autoimmune reaction too, in which the body effectively attacks itself, though the science is still vague on what role, if any, vaccines can play in that. Other possible problems include simple injury to shoulder, when the vaccine needle penetrates the bursa—the sac of cushioning fluid that protects the joint. For many of these problems, the claimants are adults, not kids.

In rare cases, severe neurological reactions have been observed too, but that very rarity makes it impossible to determine if they were caused by the vaccine or were a mere coincidence in timing. Still, the no-fault rule of the VICP doesn’t seek proof of causation, which means that claims like this are covered—and those are the ones that drive up the overall average.

“In cases in which there is a lifetime injury, the award will be the equivalent of many millions of dollars,” says New York-based attorney Robert Krakow, who has represented petitioners in hundreds of vaccine injury claims. “It could be $20 million over a lifetime.” Just three such claims a year—out of the many millions of vaccines administered annually—0ver the course of the 27 years the VICP has been in effect can account for half of the total dollars spent on awards.

No surprise, since the rise of the anti-vax fringe, the VICP has been inundated. In 1998, the year U.K. physician Andrew Wakefield published his fraudulent paper linking the MMR vaccine to autism, just 325 injury claims were filed, 181 were dismissed and 144 were compensated. In 2010, Wakefield’s fraud was exposed, his paper was withdrawn and he was stripped of his license to practice medicine in the U.K. But the anti-vax hysteria had been unleashed, driven in part by anti-vaccine drum-bangers like Jenny McCarthy. The following year, 1,637 claims were filed. In 2012, that figure rose further, to 2,702. The number of awards granted increased as well, but still remained in the low triple digits—266 in 2011 and 263 in 2012.

Certainly, vaccine science is not fixed, and different circumstances lead to different law. The case of Hannah Poling, the 9-year-old Georgia girl who, in 2008, received a $1.5 million award when the court agreed that vaccinations contributed to her later-onset autism, rocked the medical community and only worsened the anti-vax panic. But Poling was a special case; she was suffering from an underlying disorder of the mitochondria, or the energy-processing organelle in the cells. This made her vulnerable to any oxidative stress that could, in theory, be caused by vaccines. Mitochondrial disorders are increasingly being cited in vaccine court claims, but the conditions are not common and are poorly understood. “The belief is that the vaccine triggers a decompensation,” says Krakow, “but this is controversial.”

What’s not controversial is the far bigger picture, which is that medicine has never been about eliminating all risks, but about minimizing and balancing and coolly considering them. Childhood diseases are a manifest danger, capable of sickening hundreds of thousands or even millions of kids each year. Vaccines, which offer powerful—if imperfect—protection, all-but eliminate that peril. Yes, they introduce a tiny bit of their own risk, but they still leave children far safer than they otherwise would be. For the literal one in a million who are harmed, the VICP stands by to help. For the rest, it’s the vaccines themselves that do the helping.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME medicine

Why ‘Female Viagra’ Isn’t Really Like Viagra

There are key differences between the two drugs

The drug flibanserin, which is being sold by Sprout Pharmaceuticals under the brand name Addyi , is the first drug approved to treat a lack of female sexual desire. Some are calling it ‘female Viagra’—but while both pills are meant to improve sex lives, the similarities end there.

Viagra is an erectile dysfunction treatment and increases blood flow to man’s genital area to help him achieve and maintain an erection. But flibanserin doesn’t treat a physical ailment, and the U.S. Food and Drug Administration (FDA) says it hasn’t been shown to enhance sexual performance. Instead, it aims to improve lagging libido in premenopausal women who are distressed by their low desire for sex, a condition called hypoactive sexual desire disorder (HSDD).

MORE: Female Viagra’ Drug Approved By FDA

Scientists understand how flibanserin works, but not necessarily why the mechanics of the drug lead to improved sexual desire and less stress. The drug targets neurotransmitters thought to be involved in sexual desire; it increases dopamine and norepinephrine levels while decreasing serotonin levels. In an email to TIME, a spokesperson for Sprout Pharmaceuticals said dopamine and norepinephrine are responsible for sexual excitement, and serotonin is responsible for sexual satiety and inhibition.

Also unlike Viagra, flibanserin is a medication taken every day (close to bedtime.) Viagra is only taken as needed. Data from the makers of Viagra suggest that the drug helped approximately four out of five men get and maintain erections. About 85% of men taking 100 mg of Viagra had hard erections compared to 50% on placebo. Data from flibanserin—which included three 24-week randomized, double-blind, placebo-controlled trials in about 2,400 premenopausal women with HSDD—is less impressive. The women who took a 100 mg nighttime dose of the drug showed that on average, being treated with flibanserin increased the number of sexually satisfying events by 0.5 to one additional event per month over placebo and increased desire by 0.3 to 0.4 points over placebo.

MORE: See How ‘Female Viagra’ Works

One of the reasons critics opposed the approval of flibanserin is that they believe the benefits of the drug are not great enough to override possible side effects. When the FDA approved the drug Tuesday, it cited serious risks that could come from taking flibanserin and drinking alcohol, which include severely low blood pressure and loss of consciousness. For that reason, among others, the FDA said the drug will only be available through specially certified health care professionals and certified pharmacies and will include a boxed warning of its side effects.

“There is no black box warning [for Viagra]. They tell you not to take it on a full stomach, but that’s not a medical restriction,” says Leonore Tiefer, a clinical associate professor of psychiatry at NYU School of Medicine. “This drug, [flibanserin], has all of these limitations, and it affects the brain.”

The decision to take flibanserin lies with women and their physicians, but it may be in a consumer’s best interest to understand the distinctions between the little blue pill and the little pink one.

TIME medicine

Pharmaceutical Giant Amgen Settles for $71 Million For Misleading Consumers

Amgen Pharmaceutical
Robert Galbraith—Reuters Amgen's office in San Francisco on Oct. 21, 2013.

The company was accused of "making unapproved and unsubstantiated claims about prescription drugs" Aranesp and Enbrel.

Pharmaceutical company Amgen Inc. has settled with 48 states and the District of Columbia for $71 million after being accused of illegally promoting two drugs for “off-label” uses, New York State Attorney General Eric Schneiderman announced Tuesday.

The pharmaceutical company was accused of promoting its two brands, Aranesp and Enbrel, for uses not approved by the FDA.

“Pharmaceutical companies are prohibited from making unapproved and unsubstantiated claims about prescription drugs,” Schneiderman said in a press release. “Consumers need to have confidence in the accuracy of claims made by pharmaceutical companies.”

Aranesp is an anemia medication that works by stimulating bone marrow production of red blood cells. Enbrel is used to treat multiple conditions, notably chronic and severe plaque psoriasis.

A complaint filed against Amgen said Aranesp was promoted for longer dosing frequencies and for cancer-caused anemia, for which it had neither FDA approval nor scientific proof. Enbrel was promoted for mild cases of plaque psoriasis, despite being only approved for severe cases; it was also advertised to be far more effective than scientifically shown, according to the complaint.

As part of the settlement Amgen will have to change its advertising strategy to exclude it of its current misleading intent and is forbidden from continuing its current claims.

In a statement, Amgen responded by saying it “is pleased to have this matter resolved, and remains committed to fulfilling its mission to serve patients.”

TIME medicine

Children as Young as 11 Can Now Take OxyContin

Opana OxyContin Morphine Pain Killers Drugs
Rich Pedroncelli—AP Schedule 2 narcotics Morphine Sulfate, OxyContin and Opana are displayed for a photograph in Carmichael, Calif.

There will be strict limits on when it is safe to prescribe

The powerful painkiller OxyContin can now be prescribed to children as young as 11, the Food and Drug Administration has decided.

The FDA requested that the drug’s manufacturer, Purdue Pharma, conduct studies to determine the safety of OxyContin for pediatric patients, and found that it would be safe for those in the 11 to 16 age range to take the drug, NBC News reports. However, before a doctor can prescribe OxyContin, the child must already be responding to and tolerating a certain dosage of opioids, so the doctor is sure that the patient will be safe.

OxyContin is used as a long-release version of oxycodone; it is to be taken every 12 hours rather than every 4 to 6 hours for long-term pain management. Comparatively few children require such a drug, which is often used in response to major surgery, cancer or injuries. The drug is notoriously abused by drug addicts, and was reformulated in 2010 to making crushing and snorting or injecting it more difficult. The only other long-release opioid with FDA labeling for pediatric patients is the Duragesic patch, which uses fentanyl.

TIME health

This Is How Legionnaires’ Disease Got Its Name

Aug. 16, 1976
TIME The Aug. 16, 1976, cover of TIME

It all goes back to an American Legion convention in 1976

The news that Legionnaires’ disease has killed a dozen New Yorkers this summer—and that an inmate at Rikers Island has been diagnosed as well—has put the illness in the headlines and hospitals. Luckily, these days, most people who experience symptoms can be treated successfully with antibiotics.

But that wasn’t the case when the disease was first discovered. Not only did Legionnaires’ prove fatal to many affected by its first notable outbreak, but those victims didn’t even know what was making them sick.

The legionnaires after whom the disease is named were attendees at an American Legion convention in Philadelphia in July of 1976. They were veterans like Ray Brennan, Frank Aveni and Charles Seidel, who went to an ordinary meeting, fell ill shortly after with chest pains and high fevers, and died not long after. They had spent time all over the city, eaten in restaurants and traveled home in a variety of ways. In a cover story that August about the “disease detectives” who were trying to find “the Philly killer,” TIME captured the panic that resulted from the outbreak. The magazine noted many friends and neighbors of John Bryant Ralph, another Legionnaire, did not attend his funeral for fear his disease might be catching.

For many Americans, the Philadelphia outbreak was the first time they were aware of the work done by the Centers for Disease Control, a then-obscure organization that went to work trying to figure out what was killing the Legionnaires:

Like police work, most medical sleuthing is done in the field by the “shoe leather” epidemiologists, some from the state’s public health service, others from the CDC. They crisscrossed the state to interrogate every one of the stricken Legionnaires and the families and friends of the deceased. Their quest: a common denominator, a set of experiences that would link all the victims, such as meals taken together, rooms in the same hotel, exposure to similar contamination. Their method: careful questioning and cross-referencing.

“Hello, I’m part of the medical team investigating this weird disease,” said Dr. Stephen Thacker, 28, as he sat down beside Thomas Payne’s bed in Chambersburg Hospital. “How do you feel? When did you first feel sick? Where did you eat and stay in Philadelphia? When did you arrive there? When did you leave? Did you go to the testimonial dinner? Or the go-getter’s breakfast? Did you go to the hospitality rooms for the state commander or other officials? Did you have any contact with pigs?”

In some ways the detectives’ legwork raised more questions than it answered. A check of the hotels at which the conventiongoers had stayed revealed no outbreak of the mysterious illness among employees who had come in contact with the Legionnaires. The investigators could find no evidence that any of the victims had been exposed to pigs, which have been implicated as the animal reservoir for the swine-flu virus. Nor could the disease detectives explain another apparent contradiction: why some people developed the disease, while others, who ate the same meals, drank the same drinks or shared their rooms during the convention, did not.

The disease remained elusive. “There’s an outside chance we may never find out the cause,” CDC Director David Sencer told TIME. “I think we will. But there are times when disease baffles us all. It may be a sporadic, a onetime appearance.”

Eventually, the initial outbreak tapered off and, though nearly 200 had become ill and 29 had died, fear tapered off too. It was clear that whatever it was, it wasn’t spreading—but, though public interest waned, the CDC kept working. It wasn’t until months later that the mystery was actually solved.

“Five months after the convention, [CDC microbiologist Joseph McCade] took another look at some red sausage-shaped bacteria and concluded that they were the culprits,” TIME later explained, in a 1983 cover story about the CDC. “They had festered in the water of the hotel’s cooling tower and had been carried through the air as the water evaporated.”

Read the 1976 cover story, here in the TIME Vault: Tracing the Philly Killer

TIME fertility

Frozen Eggs Have A Lower Live Birth Rate Than Fresh Eggs, Study Says

An in-vitro-fertilization in progress
BSIP/;UIG/Getty Images An in-vitro-fertilization in progress

You may be less likely to have a baby with a frozen egg than with a fresh one

Parents attempting to start a family using donated or frozen eggs are often told that frozen eggs behave just like fresh ones, but a new study has found that in-vitro fertilization with frozen eggs has a significantly lower live birth rate.

According to a study published in the Journal of the American Medical Association, IVF cycles that use frozen eggs have a lower live birth rate than cycles done with fresh eggs. Researchers led by Dr. Vitaly A. Kushnir from the Center for Human Reproduction examined data from 11,148 egg donation cycles performed in 380 U.S. clinics in 2013, including 2,227 that used frozen eggs. For each IVF cycle, the live birth rates were 50% with fresh eggs, and 43% with frozen eggs. For each embryo transfer, 56% of embryos created with fresh eggs resulted in a live birth, compared to 47% of embryos created with frozen eggs.

Eggs are frozen using a quick-freeze vitrification process, a development which caused the American Society of Reproductive Medicine to lift the “experimental” label from egg-freezing in late 2012. Eggs can be frozen either to delay the mother’s own fertility, or to donate to another couple. But just because egg-freezing is no longer considered “experimental” doesn’t mean it’s a sure thing.

Read More: What You Really Need to Know About Freezing Your Eggs

Dr. Kushnir says the disparity in live birth rates could be partly explained by the fact that patients tend to start with a larger number of fresh eggs than frozen eggs, since donated frozen eggs are often packaged in smaller bundles. “If you start with 10 embryos rather than 5 embryos, you have a better chance of selecting the best embryo,” he says. “But it could also be that freezing and thawing diminishes the quality of the egg.”

He noted that while freezing eggs is no longer considered “experimental,” it’s still not a foolproof procedure, and emphasized that it tends to be easier to freeze embryos than eggs. “With an egg, its only one cell; it either makes it or it doesn’t,” he says.

This study did not adjust for age or other donor characteristics, which means it’s important to interpret with caution. But it’s the first widespread study that compares live birth rates from frozen eggs to live birth rates from fresh ones. Until now, doctors have relied on anecdotal evidence to reassure their patients that frozen eggs behave exactly like fresh ones, an idea that has contributed to the growing popularity of elective egg-freezing as a method of fertility preservation.

Another important thing to note is that this study measured frozen eggs from egg donors, who tend to be much younger than women who electively freeze eggs for fertility preservation. Egg donors tend to be between 18-25 (the cutoff age for Egg Donor America, one egg donation center, is 29) while women who freeze their own eggs tend to be in their mid-late 30s. Since most doctors think egg quality can decline with age, women who freeze their own eggs might see even lower live birth rates than the donor eggs in this study.

TIME vaccines

How to Change an Anti-Vaxxer’s Mind

TIME.com stock photos Health Syringe Needle
Elizabeth Renstrom for TIME

Jeffrey Kluger is Editor at Large for TIME.

It's not easy, but a new study suggests one way to help persuade parents to vaccinate their children

Let’s take a moment and praise anti-vaccine parents. Really. They’re wrong on the science, wrong on the politics, and deeply, morally wrong to deny their own children a simple disease preventive that they themselves likely enjoyed growing up. But like all parents everywhere, they’re acting on a simple, powerful impulse: to keep their children healthy.

That’s a very noble goal, but it’s also one of the things that makes it so bloody hard to change their minds on the topic of vaccines. Public service campaigns don’t work; nor do one-on-one explanations of why the rumors about a vaccine-autism link are wrong. In some cases, there is even a backfire effect: the greater the effort expended to persuade the anti-vaxxers, the more convinced they become that they’re right.

So it’s extremely good news that researchers at the University of Illinois Urbana-Champaign may at last have come up with a way to cut through the misinformation and get the truth across: Don’t just tell parents to vaccinate their children, show them what happens if they don’t.

In a study published in the Proceedings of the National Academy of Sciences, a team led by graduate student Zachary Horne recruited a sample group of 315 people—both parents and non-parents—and first conducted a simple survey designed to measure their pre-existing attitudes to vaccines. The subjects were asked to respond on a six-point scale, from “strongly agree” to “strongly disagree,” to five statements that included, “The risks of side effects outweighs any potential benefits of vaccines” and “I plan to vaccinate my children.”

All of the subjects were then divided into three groups: One group was given material to read about the latest research showing that autism and vaccines are in no way related. The second group was given a paragraph to read written in the voice of a mother describing what it was like when her child contracted measles; three pictures of children with measles, mumps and rubella; and written warnings about the importance of vaccinating children. The third group, serving as a control, read material on an unrelated science topic.

When the three groups’ attitudes to vaccines were tested again, the results were striking. Both the control and the so-called “autism correction” group showed a slight uptick in their approval of vaccines, but in neither case were the numbers terribly significant. The group that had learned about the wages of vaccine denialism changed markedly, however, with increased approval rates five times larger than those in the autism correction group and six times larger than in the control group.

“Rather than attempting to dispel myths about the dangers of vaccinations,” the researchers wrote, “we recommend that the very real dangers posed by serious diseases like measles, mumps and rubella be emphasized.”

As TIME reported in the Oct. 6, 2014 issue, this is precisely the approach that worked during the mumps outbreak in Columbus, Ohio last year. College students were nonchalant about getting vaccinated, but when they learned that the disease can lead to sterility in both men and women, they were a lot more inclined to step up for their shots. “I was pretty freaked out,” one Ohio State University student said. “I didn’t know mumps could lead to any of that.”

The power of the show-don’t-tell approach is nothing new. It’s the reason behind the anti-tobacco shock ads showing people dying of lung cancer, as well as the surgery fund-raising ads showing photos of babies with cleft lips. The trick in all of these cases is getting people to act fast. If too much time elapses between image and potential action, the power of the message is lost.

For that reason, Horne and his co-authors suggest that future research should look at the effectiveness of including the kind of counseling that was used in their study during routine well-baby visits, when vaccinating the child on the spot is an option. After all, the effect of scaring a parent straight may be temporary, but the damage done to a child who contracts a vaccine-preventable disease can be for life.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

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