Olivia was 7 years old when she caught the measles. She seemed to be recovering when the disease took a turn. She felt sleepy. Her fingers and her mind weren’t working together. The measles had triggered encephalitis, an acute inflammation of the brain. “In an hour she was unconscious. In twelve hours she was dead,” her father, the children’s book author Roald Dahl, once wrote.

Olivia contracted the measles in 1962, before the measles vaccine was available to the public. By the year 2000, measles was eliminated in the U.S. Today it’s coming back.

Storytelling matters and, in many cases, it can mean the difference between life and death. The controversy over the measles vaccine is an example of what can happen when leaders in a particular field—the healthcare community in this case—begin to lose control of the narrative.

As you know, America is seeing a small, but growing number of parents who are choosing not to vaccinate their children against measles. The Centers for Disease Control and Prevention (CDC) and the White House are not taking any chances. Appearing on The Today Show, President Barack Obama called the science “indisputable.” According to Obama, “We’ve looked at this again and again. There is every reason to get vaccinated, but there aren’t reasons to not…you should get your kids vaccinated.” Obama urged parents to “look at the science, look at the facts.”

The fact that vaccines save lives might be indisputable, but the problem is we have too many facts and too few stories.

Leaders often rely on emotionless facts to influence people who are emotional beings. The CDC director, Dr. Tom Frieden, appeared on Sunday’s Face The Nation to warn Americans that the country could see a “large outbreak” of measles. He gave viewers plenty of facts, and no individual stories.

In Frieden’s 4-minute CBS interview, viewers saw plenty of graphs and they learned plenty of facts. They learned that in California last year 8 percent of kindergarteners, 41,000 children, failed to get required immunization against measles. In Oregon the number is 6.8 percent and in Pennsylvania, 15 percent of kindergarteners weren’t immunized. Four minutes of statistics and no personal stories. “We have to make sure measles doesn’t get a foothold in the U.S. The science is clear. The vaccine is safe and effective.”

Yes, the science is clear and Frieden does an excellent job of delivering that message.  But it’s also clear that facts alone don’t influence actions—stories do. In an essay for the Journal of the American Medical Association (JAMA) Dr. Zachary Meisel and Dr. Jesse Pines explain that many healthcare organizations “shun individual stories.” The doctors say that those who “espouse only evidence—without narratives of real people—struggle to control the debate.” They argue that facts and figures are essential, but “insufficient” to overcome preconceived beliefs.

Healthcare leaders can continue to offer mountains of evidence confirming the safety and effectiveness of vaccines, but one compelling story can trump years of data. The power of story explains why an attractive celebrity who tells the story of her autistic son—and links vaccines to the rise of autism “without a doubt in my mind”—can exert an outsized influence over the public narrative.

The best way to “neutralize stories that promote disproven theories” is by supplying the public with “counter narratives,” according to the JAMA article. In other words, parents need to hear stories, and the more detailed the stories, the more impactful they become. The CDC ‘fact’ that January saw 102 confirmed cases of measles in 14 states is largely meaningless to most Americans. Some medical experts are reminding the public that a 1998 study in a medical journal that purported to link the MMR vaccine to autism was retracted because the data was fabricated. Important information to be sure, but it’s still “fact.”

People need to hear counter-narratives, the true and deeply disturbing stories behind the estimated 145,000 individuals around the world who lost their lives to measles last year.

Olivia’s story was published on a British site called the Vaccine Knowledge Project, an initiative funded by the Oxford Biomedical Research Center.  The information is “designed with a non-specialist in mind.” The people behind the site know that ‘non-specialists’ relate to stories, which is the why the site is stuffed with heart-wrenching stories of individuals who suffer from measles.

If you watch the videos, you will see the story of Sarah Clow who was not vaccinated against measles as a child. The measles attacked her entire body, including her brain. She was in a coma for eight weeks and is now deaf and partially blind.

You will see the story of Sarah Walton who caught the measles when she was 11 months old. Although she recovered, Sarah contracted a viral infection connected to her measles 24 years later.  It destroyed her central nervous system. Sarah’s mother, who is Sarah’s caregiver, narrates the video by Sarah’s bedside. Sarah is largely unresponsive with a tube in her nose. I have two daughters so I’ll warn you now—if you choose to watch the videos bring some tissues.

As an expert in the spread of diseases, Melinda Gates knows facts. She also knows how to deliver facts effectively by wrapping them in story. “Women in the developing world know the power of vaccines,” she told the Huffington Post. “They will walk 10 kilometers in the heat with their child and line up to get a vaccine because they have seen death. We’ve forgotten what measles deaths look like…but in Africa, the women know death and they want their children to survive.”

If we have forgotten what the illness looks like, then only individual stories can remind us. Stories are irresistible because human beings are hardwired for empathy. Although the facts might be indisputable, it’s also indisputable that the power of story is the most effective way to turn facts into action.