In May 2016, Roberto Burioni, a virologist at Vita-Salute San Raffaele University in Milan, Italy, was asked to appear on a popular TV talk show to face off against two opponents of vaccines—a former DJ, Red Ronnie, and an actress and TV personality, Eleonora Brigliadori. The host gave most of the air time to the Italian celebrities. Then, with just a few minutes left, he turned to Burioni.

Burioni realized he didn't have time to make the usual arguments about statistics and scientific uncertainty, so he kept his message simple: "The Earth is round, gasoline is flammable, and vaccines are safe and effective," he said. "All the rest are dangerous lies."

"It went off like a bomb," Burioni recalls. Emails from viewers poured into the show, with some questioning how the publicly funded TV network hosting it could allow such ill-informed personalities to speak about medicine. Burioni took up the theme on his Facebook page, asking how one branch of government could broadcast lies about vaccines while its health agency promoted immunization. More than 5 million people responded to his comments. Radio journalist Alessandro Milan called Burioni's rebuttal to Red Ronnie "the 13 most beautiful words heard on TV in the last year."

So began the unlikely media career of Roberto Burioni. In just a few years, he has gone from being a respected but little-known professor to a major media personality and an internet savvy advocate for science. In a country where the government has sometimes promoted dubious medicine, such as unproven stem cell therapies, Burioni has become an outspoken advocate for scientific evidence on vaccines and other medical topics, and a harsh critic of pseudoscience. Nearly 480,000 people now follow him on Facebook—an impressive number in a country of 60 million. A web page he and colleagues established to provide general health information gets more than 100,000 visitors per month.

Burioni, with his shock of graying hair, peaked eyebrows, and ironic smile, appears often on TV and at public events. His four recent science books for popular audiences have become best sellers. The Italian edition of Forbes magazine named him one of Italy's top five internet game changers, and a former health minister nominated him for Italy's gold medal in public health.

He’s the one scientist who stood up and said, ‘This is bullshit.’

Internet prominence brings trolls, and Burioni has been forced to worry about security. Some respected health researchers and journalists have also been critical, saying his blunt, even abrasive manner inflames an already polarized conflict. But many public health experts credit him with changing Italy's debate about vaccination and elevating the profile of science there.

"I think he's had a major impact on the public's understanding on the topic of vaccinations and science in general," says Pier Luigi Lopalco, who studies epidemiology and public health at the University of Pisa. "He's re-established the right of scientists to speak directly to the people without having a DJ or actor intervene."

Burioni might seem an unlikely media personality. He followed a rigorous academic track: a medical degree in Rome; a Ph.D. in microbiology in Geneva, and several years of postdoctoral research at the U.S. Centers for Disease Control and Prevention, the University of Pennsylvania, the University of California, San Diego, and the Scripps Research Institute. As a professor in Milan, he develops monoclonal antibody therapies for herpes, hepatitis C, and other viral diseases—work that has led to 30 international patents.

He made his first foray into social media in 2015, when a friend who had created a Facebook group for mothers asked him to write an explainer about vaccines. Burioni, already irked by Italy's growing antivaccine movement, agreed. "I felt it was my duty to do something as a doctor and a professor and as a father of an 8-year-old daughter." He worried that the push to resist vaccinations could put her and her classmates at risk. He posted a five-point rebuttal of popular vaccine misconceptions and conspiracy theories—including the notion that drug companies promote vaccination in order to increase profits. "Pharmaceutical houses earn much more from disease cures than from vaccines," he declared. "So if you don't vaccinate your children, the pharmaceutical multinationals will be sincerely grateful to you."

That post and others hit a nerve. Within weeks his social media followers grew from about 100 to six digits. A voice like Burioni's—that of an expert who sees no reason to mince words or suffer fools—was evidently what many Italians were looking for.

As in many Western nations, concern about vaccines had surged in Italy in the late 1990s after U.K. doctor Andrew Wakefield published his now notorious study in The Lancet linking autism to the measles, mumps, and rubella (MMR) vaccine. The study was later shown to be fraudulent, and Wakefield lost his medical license. But that didn't stop him from continuing to proselytize against vaccines or prevent vaccine opponents from embracing his study.

The Italian government insisted vaccines were safe, but a series of medical scandals had damaged its credibility. The most recent involved an experimental treatment called Stamina therapy, developed by an entrepreneur who claimed to be able to regenerate nerves from stem cells and cure conditions such as Parkinson's disease and muscular dystrophy. The inventor, Davide Vannoni, received huge fees from desperate patients, despite having produced no clinical studies or peer-reviewed papers. Scientist denounced the treatment, and the Italian Medicines Agency ruled it unsafe. But the Italian Senate, bowing to public opinion, permitted doctors and hospitals to administer it and funded a nearly $4 million clinical trial that was never completed.

Stamina therapy was finally outlawed in 2014, and Vannoni received a 22-month suspended sentence for fraud. (He died in December 2019.) Later, it was revealed that Italy's current prime minister, attorney Giuseppe Conte, won a court case in 2013 that allowed Stamina therapy to be given to a girl suffering from an incurable neurological condition. The child later died.

Courts in Italy have compounded the problem. Local judges often lack scientific expertise and are allowed pick their own consultants on technical matters. In one egregious case in 2012, a judge in Rimini relied on Wakefield's discredited research to award the family of an autistic boy more than $200,000 from the government, on the grounds that the measles vaccine distributed by the national health service caused his condition. News of the decision spread on the internet like a contagion, igniting false beliefs and conspiracy theories. "The year 2012 was identified as the breaking point in the public's confidence in vaccination in Italy," researchers at the University of Pisa wrote in a study of the web's effect on vaccinations. An appeals court reversed that judge's decision in 2015, but the damage was done.

Antivaccination sentiment infected not only the courts, but also entertainment and politics. In the late 1990s, for example, a comedian named Beppe Grillo had become famous in Italy for denouncing vaccination. Ten years ago, he co-founded the Five Star Movement, a libertarian political party that became a dominant member of Italy's ruling coalition and embraced antiscience positions.

Vaccination rates, which had been climbing since the 1990s, started to slide. Uptake of the MMR vaccine declined from a peak of nearly 94% in 2010 to just over 85% in 2015—one of the lowest rates in Europe, and well below the 95% needed for herd immunity. Almost in lockstep, the nation's measles rate climbed to the second highest in Europe, after Romania's.

That was the situation Burioni waded into when he made his appearance on Italian TV. He'd never been on TV before, and when the network called he assumed he'd be speaking to other medical experts. He was shocked to find that he'd be sharing the broadcast with two people who knew nothing about vaccines. Hence his curt reply, and the public's enthusiastic response.

As he saw it, a door had opened and he had to walk through it. The public seemed hungry for straight talk from an expert, and he obliged. "I realized that the language of social media needs to be different than the language used in conferences, with colleagues or even with patients," he says, "so I tried to use not a single difficult word." He turned instead to concrete, nonmedical metaphors in his Facebook and Twitter postings. "Does an aircraft engineer take a vote among the passengers as to how many wheels to put on an airplane?" he asked. "No—the engineer is the expert, he's trained for this job, and it's his job to decide."

When one of the largest publishers in Italy asked him to write a book on vaccines, Burioni cranked it out in 4 months. A night owl, he wrote after his wife and daughter went to bed. "I never realized that I was good at writing," he says. "Here I was at 54 years old; how would you say it—a late bloomer?"

The result, Vaccines are not an Opinion: Vaccinations Explained to Those Who Really Don't Want to Understand , was a novelty in a country where scientists rarely communicate in colloquial language. In it, Burioni explains how vaccines work, traces the history of vaccination and of vaccine denialism, and dismantles the denialists' arguments. He brings up tragic case histories of people who died young for want of a vaccine and skewers prominent vaccine opponents, such as Jenny McCarthy, who declared on Oprah that she learned her biology "from the university of Google." He hammers on the theme that you can't substitute opinion for facts. The book's popularity made him a fixture on radio and TV. "The speed of light can't be decided by a show of hands," he'd say in talk show appearances.

In his later bestsellers, Burioni widened his case against pseudoscience in Italy. "We are a country forever wobbling between science and superstition," he says. He railed against judges who ruled that unproven treatments such as Stamina therapy had to be given to patients who requested them, often in publicly funded hospitals. He also criticized the Italian public health system for reimbursing patients for homeopathy—pseudoscientific medical treatments that use an extremely dilute concentration of a substance that causes symptoms similar to those of the disease.

Burioni says he wants to promote a respect for expertise. "I know something about vaccines, viruses, and bacteria because I have been studying them for a lifetime," he writes in Conspiracy of Dunces: Why Science Can't be Democratic , his second book. "But I have no idea how to bake a cake or wire a lamp, so I go to a bakery or call an electrician."

Trouble begins, he says, when electricians, bakers, and other nonscientists feel qualified to weigh in on vaccination. The internet abets the problem, he says: Unfiltered by editors, it levels the playing field between experts and "dunces." A mass media committed to presenting both sides of every issue makes things worse. "I can't support a world in which lies are given the same dignity as the truth," he heatedly remarked on an interview show. "Enough already! Enough!" The audience burst into applause.

Burioni's books, postings, and media presence have made him a celebrity scientist in Italy akin to, say, Neil deGrasse Tyson in the United States. Hardly a week goes by without him appearing on TV or in a glamour shot in a newspaper or magazine. At a recent conference in Milan about future technologies, the audience—including many influential business leaders—swarmed him after his talk, asking for advice and autographs.

"I feel a bit embarrassed by it all," Burioni says, seeming not at all embarrassed but very much amused. (In fact he seems to relish the publicity, having recently appeared on an Italian comedy show in a version of Name That Tune .) He's proud that despite all the media appearances he hasn't missed giving a lecture and continues to work full-speed in his lab.

Yet it hasn't all been fun. His time for family and leisure has suffered. More disturbing, at one point police had to stand watch over his house after someone threatened his daughter online—one of many death threats. In 2018, Burioni and his family were vacationing at the beach town of Rimini when a vaccine opponent caught sight of him and posted on the web. Within minutes an online posse had weighed in with suggestions on how to harass him; on the advice of police he and his family went elsewhere.

He's also been the subject of more substantive criticism for his "Burioni blasts"—devastating replies to even the mildest opposition. When a Facebook follower said he was trying to figure out the vaccine issue in his own head, Burioni replied, "When you go on social media you can be reasonably sure that the interior of that head is as empty as a tire tube." He's also been known to ban even mild critics from his Facebook page and discount the work of science journalists on the vaccine issue. "This is not what you would call public outreach," says Sergio Pistoi, a science writer and molecular biologist in Tuscany.

Burioni's broadsides polarize and oversimplify a complicated discussion, adds Fabio Turone, a science writer and director of the Center for Ethics in Science and Journalism. Fewer than 1% of Italians are hard-core vaccine deniers, he says; but about 15% are "vaccine hesitant" because they have concerns about vaccines or find them hard to get. (In Italy, doctors at the public health service—not the child's pediatrician—administer vaccinations, and some health service centers closed after the budget crash of 2008.) Such people are best reached by persuasion, not mockery, Turone says.

Roberta Villa, a journalist and doctor, calls for a more empathetic approach. Her YouTube videos show her sitting at her kitchen table, a cup of coffee in hand and a drawing of Snoopy in the background, explaining that as a mother of six she understands that all parents want to protect their children. That's why scientists have examined vaccines with such care, she tells viewers. "People are much more educated than they used to be," she says. "They want to understand what we are doing to their children. So you cannot approach them in a paternalistic way."

Others appreciate Burioni's no-holds-barred style. "I know he likes to make jokes that sometimes can be seen as abrasive," says Guido Silvestri, a longtime friend and a pathologist at Emory University. "But what kind of debate can you have with someone who says that vaccines are a conspiracy to kill children? He's the one scientist who stood up and said, ‘This is bullshit.’"

Things are improving . In the summer of 2017, after the nadir in vaccination rates and the spike in preventable disease, the government passed a law that set up public education programs and requires all schoolchildren to get 10 essential vaccinations before kindergarten. Even though the law is loosely enforced, it's working. Vaccination rates have rebounded, according to Italy's National Institute of Health. After bottoming out at 85.3% in 2015, measles vaccination has risen to 94.1%, within striking distance of the 95% needed to prevent outbreaks when single cases pop up. The law has proved so effective that France and Germany passed similar laws in 2019.

Burioni and others don't claim he is responsible for the turnaround, but public health researchers say the "Burioni effect" has altered public discourse. Four years ago, googling "vaccines" in Italy would bring up a list of antivaccination groups among top results. Now, the first hits include Burioni's websites and the vaccine information sites created by the World Health Organization and Italy's health authorities. Similarly, radio and TV shows have become more likely to book scientists instead of actors and DJs to discuss vaccination, according to Lopalco and others who monitor the media.

Recently, Burioni expanded his campaign for science. In late 2018, he and half a dozen colleagues created Medical Facts, a web portal that posts news, advice, and comments on a variety of health issues. In January 2019, he and Silvestri posted a manifesto called "The Pact for Science," supporting research and education and calling for the use of objective science in government decisions. It has attracted thousands of signatures from people as diverse as the head of the left-leaning democratic party and Grillo himself, one of Italy's original vaccine deniers. In June 2019, Burioni and colleagues created a group related to the pact that will advocate for science and help local judges gather better information when adjudicating cases involving science and health.

"The world has changed," Burioni says, acknowledging both the good and "catastrophic" effects of social media. "Science needs to find a new voice—not the language of scientific congresses, but a language that's understandable, passionate, and convincing."