Covid’s Cassandra: The Swift, Complicated Rise of Eric Feigl-Ding

Eric Feigl-Ding picked up his phone on the first ring. “Busy,” he said, when asked how things were going. He had just finished up an “epic, long” social media thread, he added — one of hundreds he’s posted about society’s ongoing battle with the coronavirus. “There’s so many different debates in the world of masking and herd immunity and reinfection,” he explained, among other dimensions of the pandemic. “We at FAS, we’ve been kind of monitoring all the debates and how we’re seeing signals in which the data goes one way, the debate goes the other,” he said, referring to his work with the Federation of American Scientists, a nonprofit policy think tank. He rattled off a rapid-fire sampler of hot-button Covid-19 topics: the growing anti-vaxxer movement, SARS-CoV-2 reinfection and antibodies, the body of research suggesting masks could decrease viral load, along with a quick mention of the debate among experts about what “airborne” means.

This whirlwind tour through viral Covid-19 themes felt like the conversational equivalent of Feigl-Ding’s Twitter account, which has grown by orders of magnitude since the dawn of the pandemic. The Harvard-trained scientist and 2018 Congressional aspirant posts dozens of times daily, often in the form of long, numbered threads. He’s fond of emojis, caps lock, and bombastic phrases. The first words of his very first viral tweet were “HOLY MOTHER OF GOD.”

Made in January, weeks before the massive shutdowns that brought U.S. society to a halt, that exclamation preceded his observation that the “R0” (pronounced “R-naught”) of the novel coronavirus — a mathematical measure of a disease’s reproduction rate — was 3.8. That figure had been proposed in a scientific paper, posted online ahead of peer review, that Feigl-Ding called “thermonuclear pandemic level bad.” Further in that same Twitter thread, he claimed that the novel coronavirus could spread nearly eight times faster than SARS.

The thread was widely criticized by infectious disease experts and science journalists as needlessly fear-mongering and misleading, and the researchers behind the pre-print had already tweeted that they’d lowered their estimate to an R0 of 2.5, meaning that Feigl-Ding’s SARS figure was incorrect. (Because R0 is an average measure of a virus’s transmissibility, estimates vary widely based on factors like local policy and population density; as a result, researchers have suggested that other variables may be of more use.) He soon deleted the tweet — but his influence has only grown.

At the beginning of the pandemic, before he began sounding the alarm on Covid-19’s seriousness, Feigl-Ding had around 2,000 followers. That number has since swelled to over a quarter million, as Twitter users and the mainstream media turn to Feigl-Ding as an expert source, often pointing to his pedigree as a Harvard-trained epidemiologist. And he has earned the attention of some influential people. These include Ali Nouri, the president of FAS, who brought Feigl-Ding into his organization as a senior fellow; the journalist David Wallace-Wells, who meditated on Feigl-Ding’s “holy mother of God” tweet in his March essay arguing that alarmism can be a useful tool; and former acting administrator of the Centers for Medicare and Medicaid Services Andy Slavitt. (“We all learn so much from you,” he tweeted at Feigl-Ding in July.) Ronald Gunzburger, senior adviser to Maryland Gov. Larry Hogan, even wrote a letter to Feigl-Ding attesting to how his “intentionally provocative tweet” in January “elevated the SARS-CoV-2 virus to the top of our priorities list.”

But as Feigl-Ding’s influence has grown, so have the voices of his critics, many of them fellow scientists who have expressed ongoing concern over his tweets, which they say are often unnecessarily alarmist, misleading, or sometimes just plain wrong. “Science misinformation is a huge problem right now — I think we can all appreciate it — [and] he’s a constant source of it,” said Saskia Popescu, an infectious disease epidemiologist at George Mason University and the University of Arizona who serves on FAS’ Covid-19 Rapid Response Taskforce, a separate arm of the organization from Feigl-Ding’s work. Tara Smith, an infectious disease epidemiologist at Kent State University, suggested that Feigl-Ding’s reach means his tweets have the power to be hugely influential. “With as large of a following as he has, when he says something that’s really wrong or misleading, it reverberates throughout the Twittersphere,” she said.

Critics point to numerous problems. Not too long after his “holy mother of God” tweet, for example, Feigl-Ding took to Twitter to discuss a titillating but non-peer-reviewed paper that some readers interpreted as evidence that SARS-CoV-2 was engineered in a lab; once the authors retracted the pre-print, he deleted a series of tweets from the middle of the thread. In March, Feigl-Ding tweeted a CDC graph as evidence that young people were “just as likely to be hospitalized as older generations,” but failed to mention an important detail about the age ranges represented in the graph’s bars, which didn’t actually support that claim. In August, he tweeted his support for a proposition to allow people early access to a vaccine. After criticism from epidemiologists, bioethicists, doctors, and health policy experts, Feigl-Ding deleted a few tweets at the beginning of his thread, saying they were “confusing” and “murky.” (He also argued that his critics were “spreading misinformation about what they think I said.”)

More recently, Feigl-Ding wrote a thread about coronavirus particles in flatulence, which drew criticism from researchers.

“With as large of a following as he has, when he says something that’s really wrong or misleading, it reverberates throughout the Twittersphere,” Smith said.

Even when his public exclamations are technically accurate, Feigl-Ding’s critics suggest that they too often invite misinterpretations. In a thread about the first study of a Covid-19 outbreak on an airplane, for example, Feigl-Ding failed to mention the important caveat that researchers suspected all but one case occurred before people got on the airplane. In another, Feigl-Ding appeared to summarize a Washington Post piece on a coronavirus mutation, but omitted crucial phrases — including the fact that just one of the five mentioned studies was peer-reviewed. It wasn’t until the sixth tweet in the thread that Feigl-Ding mentioned the important detail that the “worrisome” mutation doesn’t appear to make people sicker, though it could make the virus more contagious.

To Angela Rasmussen, a Columbia University virologist, this represents a pattern. “[T]his is his MO,” she wrote in an email. “He tweets something sensational and out of context, buries any caveats further down-thread, and watches the clicks and [retweets] roll in.”

Such critiques of Feigl-Ding’s particular brand of Covid-19 commentary are by no means new, and previous articles — in The Atlantic as far back as January, for example, New York Magazine’s Intelligencer in March, the Chronicle of Higher Education in April, and in The Daily Beast in May — have explored questions about his expertise in epidemiology (his focus prior to Covid-19 was on nutrition) and whether his approach to public health communication is appropriate or alarmist. But as his influence has grown, and as the pandemic enters a much more worrying phase, critics have continued to debate whether Feigl-Ding, for all his enthusiasms, is doing more harm than good. Some complain that Feigl-Ding’s army of followers can be hateful when other scientists publicly disagree with his tweets. Others say that Feigl-Ding himself has been known to privately message his critics — a tack that some found unwelcome.

For his part, though, Feigl-Ding says many of his critics’ disagreements with him have come down to a difference in style. “Sometimes it’s a matter of a philosophical approach about tone: Should I say ‘whoa’ or ‘wow?’” he said — adding that he thinks of those words as a type of “subject line” for a tweet. “Some people don’t like the all-caps initial thing, but it’s more of a stylistic thing. And of course, some people think: ‘This tweet is sensational.’ I’ve heard that,” he said — adding that, indeed, he has contacted critics, but always in a professional capacity. “I [direct-message] a lot of people,’ he said, “sometimes email them when I have a question.

“We have spirited debates,” he added.

“[T]his is his MO,” Rasmussen wrote. “He tweets something sensational and out of context, buries any caveats further down-thread, and watches the clicks and [retweets] roll in.”

But Feigl-Ding makes no apologies for trying to amplify and draw attention to the seriousness of Covid-19. Sounding the alarm — even if sometimes imperfectly — Feigl-Ding insists, is a moral obligation. “The whole New York Magazine article by David Wallace-Wells, the whole article was that alarmism is needed,” he said. “It was arguing for the case of alarmism. How do we listen to the early alarms? We could have reacted faster. It’s getting people to sit up from the chair and pay attention.”

He also argues that in some cases, his Twitter influence has helped to shape policy. Specifically, he mentions a thread — which began with the words “BLOODY HELL” — criticizing broadcast company Sinclair for their decision to air a segment featuring Judy Mikovits, the star of a popular, discredited video that surfaced various conspiracy theories about the pandemic. (The media watchdog group Media Matters for America first reported on Sinclair’s plans a couple days before Feigl-Ding’s tweet.)

That tweet got “more impressions than CNN,” Feigl-Ding said, adding that hours after making it, Sinclair announced they would postpone airing the segment. Two days later Sinclair decided not to air the interview at all. “Clearly, it had an impact. That’s what I’m going for,” he said.

“The alarmism got action,” he added.

Whether or not his critics agree with that assessment, there’s little doubt that Feigl-Ding — who, depending on the context, might best be described as a scientist, a politician, an advocate, and a self-styled public health Cassandra — continues to opine, with great emotion and inflection, on myriad Covid-19-related topics, using phrases like “I’m crying”; “whoa”; “buckle up,” and “worrisome.” And on any given day, it’s easy to find other experts picking apart a Feigl-Ding tweet, explaining what he’s gotten wrong, or what nuance he’s left out.

Sometimes, Feigl-Ding is driven to clarify his position, or even delete tweets. And where his detractors suggest that his missteps are more than mere nuisances, Feigl-Ding characterizes his critics as staid scientists who want him to “stay in his lane.” Indeed, when asked about their concerns, he often steers the conversation away quickly, saying their interpersonal issues are a distraction from what this moment needs: more people like him.

The high points of Feigl-Ding’s career have been repeatedly recounted in the news media — a point he seemed keen to emphasize in recent phone calls. “Everything I’ve ever said, there’s articles for it,” he said.

In those articles, Feigl-Ding shared versions of the same anecdotes he relayed in interviews with Undark. A Science article detailed his 2018 run for Congress, as well as the highlights of his childhood: that he spent his earliest years in Shanghai, before immigrating to the U.S. at age five; that he didn’t have a lot of friends growing up (“Imagine a chubby kid with a double chin,” he said, recounting how cruel classmates had called him “ching chong” and “pan face”); that instead of cartoons, he watched documentary series on psychology and statistics. And the media coverage goes much further back: A 2006 New York Times article described a JAMA study Feigl-Ding co-authored that provided further evidence that the drug rofecoxib, known to consumers as Vioxx, was associated with heart and kidney issues, after which “my phone did not stop ringing for a week, or two weeks,” he said. A 2007 Newsweek article featured the Facebook campaign Feigl-Ding started in support of breast cancer research. A 2011 New York Times article details the tumor doctors found in his chest at age 17, which turned out to be a benign teratoma, but launched Feigl-Ding’s interest in public health.

While Feigl-Ding is eager to discuss his successful public ventures, he doesn’t bring up his less vetted projects, like Happy Vitals, a now-defunct startup he and his wife created, which sold at-home breast milk nutrition tests. He said he’d rather not talk about Health Justice For All, a “grassroots movement” and political action committee, which received few contributions from anyone other than himself. (Feigl-Ding’s documented contributions to the PAC come in the form of unpaid Facebook posts, valued at $0.011 per impression.) He’s also not eager to talk about his failed 2018 political run to represent Pennsylvania’s 10th district in Congress. “If I run again, I don’t want a completely blunt exposé of how difficult it was,” he said. When asked if running again is something he’s considering, her responded: “Someday. Someday. I don’t want to — someday, maybe. Let’s just say maybe.”

Feigl-Ding also glosses over his decision to leave medical school, which he enrolled in briefly after completing his Harvard degree. “I realized life’s about what you do, not the number of letters behind your name,” Feigl-Ding said, “and at that point, I already had dual doctorates in two other things, and you know, pursuing a medical degree would’ve been a little bit overkill.” He is fond of talking about the “letters behind your name”; he used the phrase in a 2017 lecture at the University of Connecticut, as well as in a 2018 interview with the Harvard Crimson. Yet he also frequently refers to the impressive credentials of people he knows, even when they’re irrelevant to the conversation. These can include a double-inductee to the National Academies, or a Rhodes scholar who wrote a book with a former president’s child.

For all of Undark’s coverage of the global Covid-19 pandemic, please visit our extensive coronavirus archive.

Perhaps more than anything, though, Feigl-Ding — who says he earns most of his income as a consultant on federal projects and is unpaid for his communication and research work at FAS — frequently steers conversation towards metrics of influence, importance, or virality. In discussing how his Facebook campaign began, for example, he says he originally created two pages through the site’s now defunct Causes application; one focusing on heart disease and stroke research and another focusing on breast cancer. Unfortunately, the former “never went anywhere,” so he pivoted to concentrating on his cancer page. Eventually, the page gave him “one-click access to millions of people on Facebook,” his first foray into social media virality. “You learn to master social networks when you have your pulse on millions of people,” he said. The word “millions” is big with Feigl-Ding — he talks about the 6 million members of that Facebook campaign, the half-million dollars he says the campaign raised for cancer research, the 14 million views on a viral conspiracy video he’s publicly decried, and the millions of impressions one needs on social media to make an impact. One night, after a lengthy telephone interview, he texted a blog’s analysis that characterized him as more influential than CNN, along with a screenshot of a one of his recent tweets — one debunking hydroxychloroquine as a Covid-19 treatment. It showed that the tweet had garnered more than 2 million “impressions.”

Feigl-Ding’s descriptions of his work evoke images of him as a protagonist in a quest to fix the world’s problems. He often invokes war metaphors: He’s a “tank” against online detractors, and he refers to disagreements about Covid-19 policy as an “information war” or a “battle of the minds.” When talking about the role of viral tweet threads, Feigl-Ding recounts a Chinese parable about whistleblowers. The story, as he tells it, starts with a wizard offering a man the ability to talk to animals, but only if he agrees to never talk to humans ever again. The man accepts, but then the animals tell him an earthquake and flood will devastate his village. The man wants to warn the villagers, but if he does, the wizard will turn him to stone. He decides to do it anyway. “He made a choice and he sacrificed,” Feigl-Ding said, sighing. “I don’t want to be a martyr, but I felt like it was more important to tweet this and raise the alarm,” he says, referencing his “holy mother of God” tweet. Though the research he was citing had not yet been peer reviewed, he felt it could have important insights.

He also acknowledged the blowback he received as a result, but added: “I think it was still worth it.”

Indeed, Feigl-Ding expresses frustration about the times he wished he could have sounded the alarm sooner. “I’ve had so many of these Cassandra moments, and so many of these ‘Ah, what could have been,’ moments,” he says, mentioning his Vioxx study, the issue of toxins in the drinking water of rusting urban centers like Flint, Michigan, and even the general topic of cancer prevention. He wonders what would have happened, for example, if Toxin Alert, the website he developed with engineer Pius Lee, had launched earlier, rather than more than a year after news of Flint’s water crisis broke.

This desire to warn, to be heard, is the thread Feigl-Ding uses to connect the various facets of his career — and according to him, it’s what drove him to begin tweeting about the Covid-19 pandemic. “The world needs more whistleblowers, and those [who] whistleblow early, not just after the fact or whimper at the time,” he said, pointing to what he considers one of his own triumphs in having nudged the Maryland governor’s office into action: “Gov. Larry Hogan’s office, his chief policy adviser, credits me — that my January tweet made them stand up, sit up in their seats and start preparing.”

Feigl-Ding — often referred to as a Covid-19 expert in the media — clearly has the ear of some influential people. In addition to advising Hogan’s office, claims he’s made in tweets have been addressed by Mexican officials in government press conferences, and his tweets or commentary have recently appeared in publications like The Washington Post, Vox, and Salon. After all, who could speak to the science of the pandemic better than a Harvard-trained epidemiologist?

But epidemiology is a big field, and Feigl-Ding’s previous research focuses mostly on nutrition and cancer, different sub-areas of the field than infectious disease. Popescu, the infectious disease epidemiologist, likens this distinction to different specialties in medicine. “I’m not going to go to a cardiologist to have brain surgery,” she said. “Many of us have called attention to his lack of experience or training” in infectious disease epidemiology, she said of Feigl-Ding.

“It’s really challenging to communicate when someone really can sell themselves, like, ‘I’m a Harvard scientist, I’m an epidemiologist,’” she added.

But Feigl-Ding is, indeed, a Harvard-trained scientist and a degreed epidemiologist — though his critics argue that most of his training has focused on nutrition, not infectious disease, making him prone to mistakes. An example: In one of his most popular tweets — known widely within Twitter’s science community as the “holy moly” tweet — Feigl-Ding said he was “crying for Mexico” because the country’s testing positivity percentage was 50 percent. A full half of people being tested in Mexico were proving to be infected with Covid-19, a figure even New York, Lombardy, and Madrid didn’t approach at their “worst periods,” he wrote. “Mexico may be undergoing unprecedented #Covid19.”

The message clearly struck a nerve with Twitter users, as it received tens of thousands of retweets and more than 1,500 responses. But while all of the information in the tweet was technically true, what Feigl-Ding had actually done, according to his critics, was paint an incomplete — and alarming — picture of an out-of-control outbreak without providing upfront context about what that positivity percentage actually represented: the fact that Mexico still was not testing very many people, and that most of its testing was being done on people who were already ill. Under such circumstances, a 50 percent positivity rate would not be considered unusual. Indeed, as Boston University epidemiologist Ellie Murray wrote in a tweet, positivity percentages are “used for evaluating whether you’re doing ENOUGH tests, not estimating how much disease you have.” Along with her explanation was a screenshot of Feigl-Ding’s tweet, which she called “bad and misleading.” Feigl-Ding clarified the meaning of positivity percentages in a continuation of that thread hours later — in fact, before Murray tweeted her criticism — but those tweets received only a fraction of the attention as Feigl-Ding’s original “holy moly” tweet.

“The world needs more whistleblowers, and those [who] whistleblow early, not just after the fact or whimper at the time,” Feigl-Ding said.

Finding experts publicly correcting or critiquing Feigl-Ding’s tweets is not hard. More recently, infectious disease experts refuted his claims that the suggestion of White House coronavirus adviser Dr. Anthony Fauci that eyewear could improve Covid-19 protection meant that things were “getting serious,” and a slew of scientists — including Popescu, University of Florida biostatistician Natalie Dean, and University of California, San Francisco physician Vinay Prasad, among others — expressed concern about Feigl-Ding’s take on releasing vaccines early to certain populations.

But others suggested that the blowback from Feigl-Ding’s Twitter supporters has deterred them from raising more concerns about his missteps. “He has a couple hundred thousand followers,” said Michael Bazaco, an epidemiologist at the U.S. Food and Drug Administration and an adjunct professor at the University of Maryland. “They’re very assertive and aggressive, and I don’t want to deal with that.”

Rasmussen, the Columbia virologist, said she was initially reluctant to comment for this piece because she similarly feared online criticism from his fans. Feigl-Ding’s followers “have ganged up on anyone who criticizes him publicly,” she said, adding that her own Twitter feed has been “clogged with Feigl-Ding’s fans calling me stupid, petty, inept, gatekeeping, etc., along with the usual gendered slurs and insults.” (A search for specific instances of these terms being directed at Rasmussen on Twitter turned up few results, though evidence of Feigl-Ding defenders offering sometimes arch disagreement — and even some vulgar commentary — is easy to find.)

Dueling with strangers, Popescu said, is “emotionally draining.”

Ahead of publication of this article, Feigl-Ding pointed to complaints from other scientists on Twitter about the online argumentation style of some of his fiercest critics, including Popescu, though he declined to elaborate. “Trying to stay above it,” he wrote in an email to Undark on Tuesday, “since we need science to be respectful and publicly trusted.” Asked earlier about his own followers’ behavior, Feigl-Ding acknowledged some early issues. “Some of my early followers, those who were harassing, I actually removed them,” he said, while others eventually stopped following him. But he also said he has experienced rough treatment online himself, including by Twitter users of even greater influence. And on Twitter, too, he has responded to criticism from colleagues by pointing to his own dealings with what he called “anti-science trolls.”

Feigl-Ding may not bear any responsibility for — or even have any control over — the actions of his followers, of course, but he has also been known to privately contact his critics himself. After Murray tweeted her criticism, for example, she said Feigl-Ding messaged her privately to discuss the issue. Six other infectious disease experts that Undark spoke to say they’ve received private messages from him, often after publicly remarking on his tweets. Some, like Bazaco, say they simply ignore such forays. Popescu says that in talking with other scientists who have accepted Feigl-Ding’s messages, she discerns a pattern. “It’s always the same: ‘I want to learn, I want to be better’ — but he spends the entire time saying why he was right, giving you articles that were written about him, and how he called this and how he’s been misunderstood.”

In addition to infectious disease experts, Mexican journalist Maria Fernanda Mora said she also received messages from Feigl-Ding after she tweeted a thread questioning his reliability as a source, based on information she’d read in several articles published about him. But Feigl-Ding’s message — which included two articles about himself — arrived via Instagram, not Twitter, where Mora blocks strangers from directly messaging her. “I was truly surprised,” she wrote to Undark in a Twitter message.

When asked about these various interactions, Feigl-Ding expressed frustration, suggesting that such complaints were a “distraction” from the issues. “I don’t understand,” he said. “I’ve never said anything rude. I’ve never asked anyone to send anything rude,” arguing that his stated goal was always a polite and professional dialogue. “I’ve never kind of sent any harass[ing] messages whatsoever,” he said. “I don’t understand.”

“He has a couple hundred thousand followers,” said Bazaco. “They’re very assertive and aggressive, and I don’t want to deal with that.”

Indeed, from his perspective, Feigl-Ding said, professional disagreements ought to be considered healthy and par for the course. And science communicators are, after all, trying to accomplish the same thing. But he also said he believed that disagreements should be handled privately, to avoid conflicting information. If people see disagreement among scientists online, he reasoned, there’s a risk that they’ll ignore scientists’ messages entirely.

When this reasoning was shared with Popescu, she challenged its logic — in part because she said it seems to suggest that while Feigl-Ding can speak publicly, his critics ought not. “You’re saying we can’t disagree with you,” she added, “because we’re ‘on the same side.’”

Popescu also said she felt Feigl-Ding’s positioning himself alongside infectious disease epidemiologists toiling in the Covid-19 trenches was misleading to the public. The latter are “living it, working in it, and will continue to after this,” she said. “He’s just tweeting about it.”

Feigl-Ding says that he believes his ability to grab people’s attention is an asset, and his unique contribution to an inherent and ongoing conflict — he called it a “battle” — between science and misinformation. “Tweeting is an art form,” he said.

“If your initial tweet does not draw them in,” he added, “you’ll get maybe a respectable four or five hundred retweets. I just call that respectable, but that’s not impactful. Anything impactful, you need a thousand retweets, at least.” Once you’ve got an audience’s attention, he said — that’s when you can get “into the weeds” or use a thread to “give information that goes beyond the headlines.”

Some experts consider that a savvy formula. Nouri, the president of the Federation of American Scientists, first reached out to Feigl-Ding in February, when the organization was thinking about how to debunk disinformation around Covid-19. “Eric is one example of somebody who has managed to break through the noise,” he said. (Feigl-Ding’s Harvard affiliation has ended.) Feigl-Ding, Nouri added, not only has a large following, but his tweets weigh in on the latest news quickly. “Speed is very important when it comes to countering disinformation,” he said, noting that Feigl-Ding is also prolific, “constantly pushing material out on social media.”

When asked about critics’ concerns that Feigl-Ding’s tweets are often misleading or lack nuance, he suggests there’s a trade-off. “Whenever you want to get information out in a rapid way, in a succinct way, and in a way that really resonates with people — and you really want to grab their attention,” Nouri said, “you can’t do that effectively and at the same time have a caveat and an explanation for everything that you’re trying to convey.” Getting information out there is “a bigger value to public health,” he added, “than the fact that some aspect of the tweet may have been misrepresented.”

Devi Sridhar, the chair of Global Public Health at the University of Edinburgh, agrees that Feigl-Ding’s tweets have value. While she doesn’t agree with everything he tweets, she said, she believes he’s acting in good faith. With so much misinformation out there, it’s “all hands on deck,” said Sridhar, and at the end of the day, Feigl-Ding is on the same side as many of his critics. “Whoever wants to counter that misinformation — I’m not going to criticize them on style or their tone,” she said. “We’re all trying to get a handle on this and spread good information.”

And to be sure, there is some evidence that Feigl-Ding’s tweets have contributed to positive outcomes, and he pointed to some potential successes: He says, for example, that the day after one of his tweets about Arizona’s rising cases went viral, the state’s governor permitted local governments to create and enforce local mask orders.

Just how direct the line is between a Feigl-Ding tweet and an action in the world, of course, is difficult to discern — and not all the impacts have necessarily been in the direction Feigl-Ding would hope. Nicholas Evans, a bioethicist at the University of Massachusetts in Lowell, for example, said that within 24 hours of seeing Feigl-Ding’s tweet about the results of the since-retracted pre-print which many touted as evidence that SARS-CoV-2 was engineered, he saw Feigl-Ding referenced in support of the conspiracy theory that the virus was intentionally released by China. And Mora, the Mexican journalist, says that Feigl-Ding’s tweets about Mexico’s positivity percentage have been used by President Andrés Manuel López Obrador’s political opponents to criticize his administration’s handling of the pandemic.

Getting information out there is “a bigger value to public health,” Nouri said, “than the fact that some aspect of the tweet may have been misrepresented.”

But the central and long-running critique of Feigl-Ding — that the high profile he’s cultivated through arguably sensational, often imprecise, and above all, relentless Covid-19 messaging is problematic — suggests that many scientists simply don’t buy the notion that the urgency of the moment necessarily outweighs the need for scientific precision in public messaging during a crisis. Scientists need to be especially careful when explaining new research, said Jason Kindrachuk, a virologist at the University of Manitoba. Studies might be interesting without actually telling the public anything new about the state of Covid-19, for example. “That’s where we science communicators really have to do our diligence in providing that context back to the public,” he said. Kindrachuk is concerned that, among other things, “sounding the alarm bell too much” could needlessly concern people over trivial findings.

It also, some experts said, could lead the public to become desensitized to scientists’ concerns entirely. Paige Jarreau, a science communication scholar and vice president of science communication at the software company LifeOmic, suggested that there’s an important balance to be struck between speed and accuracy. Communicating complex ideas and nuanced arguments around the latest Covid-19 findings is indeed difficult, she said — but that makes it all the more important to think carefully about how to communicate it.

“If you’re trying to be really fast and sexy, and you put out something that breaks someone’s trust in you, maybe you ended up having to take it down because it was wrong or you were too quick to jump to sharing something and it wasn’t actually correct,” Jarreau said. “Then you’ve broken the audience’s trust.”

Feigl-Ding concedes he’s made mistakes — just as many public health experts have, he says — pointing by way of example to Anthony Fauci, who in the earliest days of the pandemic suggested that Americans needn’t be immediately alarmed about Covid-19 (though he added the situation was serious and could quickly change — as it did). Still, sometimes scientists just don’t have definitive answers to questions the public is asking, Feigl-Ding added: “We’re always trying,” he said, “to push the best available information.”

Jane C. Hu is a science journalist living in Seattle. Her work can be found at Slate, Nautilus, Wired, the Atlantic, and Smithsonian, among other publications.

UPDATE: An earlier version of this piece imprecisely described Eric Feigl-Ding as a lobbyist. While he is the founder of a political action committee, or PAC, he has never been a registered lobbyist. The story has been updated.